HARDWARE (A+)

HARDWARE (A+)

1.1 Cables and Connectors

 This paper is meant to help you with passing the A+ exam, in building your own PC, and most importantly, on the job. It is important to know how to recognize which cable is which by looking at it or its connector and how to troubleshoot any problems that may come up with them or their setup. Also my “in the field” will describe some things to remember about these cables. This will help in troubleshooting bottlenecks and other miscellaneous problems.

                In reading this, please remember that there are legacy and cutting-edge products. Even though you may have a tendency to turn nose up at the old stuff, you may have to work with it. Being able to recognize it may get you a job and respect from the senior members faster than if you have to look up all the old stuff.

                There is also the weird and bizarre factor. There are a million different types of cables out there and many of them are proprietary to a particular company or product. We see a lot of this in the laptop world. I am not here to show the weird and bizarre so when you see these types of things, look in the manual.

 We need to start with some vocabulary.

Asynchronous: Not synchronized. Communication without any timing mechanism. Instead of a timing mechanism you have communication rules. There is a start bit and a stop bit to notify the other end when communication starts and stops.

Pros: If one computer needs to send data then it can do so without having to keep stopping during each clock cycle.

Cons: With the use of start and stop bits you have 20% overhead. In other words, if you send 100 KB of information then it takes 120 KB to get it all there.

Synchronous: In this setup, data is sent as strict blocks of information. Because the timing is uniform, there is no need for a start and stop bit.

Pros: No need for extra information.

Cons: There is timing so you could say that there are blank spaces.

IRQ: Stands for Interrupt ReQuest. This is how a peripheral tells the CPU it needs its attention. There are specific numbers to tell the CPU which peripheral needs time and the priority. The priority is determined from least to greatest (i.e. 0 is the most important and 15 is the least). Most systems have 16 of these IRQs. Some older systems only have 9. This used to limit the numbers of things you can put in a system. Now technology has advanced so there is now IRQ sharing, but be mindful when working with ISA cards and older systems as you can run out fast.

Male vs. Female Connector: I’m not going too far into this, but a male connector is the side of a connection that has the prongs--like the power plug on your computer monitor. The side that goes from your monitor into the wall is the male. The outlet is the female side of the connector. NO JOKE.

DB: This term you will see in the context of DB-25 or DB-9. What this is describing is the shape of the connector. The connector has a definite shape like a capital D (also could be called a trapezoid with rounded angles).

 Now let's take a look at some of the various cable types.

Serial Port

Standard: RS-232

Connector Name: DB-9 (most common) sometimes DB-25

Transfer mode: Asynchronous

Sometimes called: COM ports

Number found on a system: 2 possible of 4

IRQ: 3(Com 2 & 4) and 4(Com 1 & 3)

I/O range: COM 1=03f8-03ff COM 2=02f8-02ff COM 3=3E8-3EF and COM 4=2E8-2EF

Max length: 50 feet

Max data rate: 1.5 Mbps (with 16550A UART)

Quick recognition:

On the computer: Male DB-9 connector. Usually 2 of them. Note: this is usually the ONLY male connector on the back of your PC. It is sometimes confused with the VGA connector because of similar physical size. But you can quickly tell the difference because a serial connector on the back of a computer is male and only has 9 pins where a VGA connector has 15 pins and is female (usually colored blue). Also, if you are looking at a really old computer, you might confuse a serial port for the video port. The really old EGA and CGA video connector used a DB-9 connector, but on the box they were female. So again, it is important to remember to look for the male aspect of this connector for identification.

On the peripheral you can quickly identify it by its female connector as shown in the image above.

Normally used with: This is normally seen on older mice and modems. Two computers can be networked together using a null modem cable. This is a serial cable that has its send and receive crossed over so the 2 computers are not trying to send information to the other's send port.

Ending comments: No discussion of serial would be complete without discussing UART (universal asynchronous receiver-transmitter) chips. This chip is the heart of your serial port. It takes your information and turns it into serial data then back again. These chips have evolved from slower to faster starting with the modern imp.

 If you want the real techie stuff go to: http://www.arcelect.com/rs232.htm

Parallel Port

Standard: IEEE-1284

Connector Name: DB-25(on PC), Centronics

Transfer mode: Synchronous

Sometimes called: LPT

Number found on a system: 1 (up to 2)

IRQ: LPT1 =7 LPT2=5*

Max length: 10 Meters (approx. 30 feet) absolute Maximum

Max data rate: 4 Mbps

Quick recognition on a computer:

                This connector stands out as the biggest connector (usually) on the back of your PC. It is usually next to the serial ports. It is a DB-25 connector on the PC and usually a Centronics 36 pin connection to the peripheral. *Warning* There are SCSI 1 connectors that look like this and will actually fit together. Just look for the SCSI symbol to tell the difference. You usually will not see a SCSI connector on a PC. But on an old Apple Macintosh you will. There is also no parallel port on a Mac to make things difficult.

Real World Notes: I once sold a Mac to a friend. He called me 2 weeks later asking me why the computer did not work. It turns out that someone had given him an old PC printer. Not knowing, he connected the parallel connector to it and turned it on. The Mac did not do anything. It did not even POST. Once he unplugged the parallel connector from the SCSI interface on the back of his Mac it worked fine with no damage.

 Also, if you plug an older device in and it is not recognized, you may need to go into Device Manager on you computer and "Enable legacy Plug and Play detection.”

 *In modern computers they can be set not to use an IRQ for an LPT port.

Normally seen on: You usually see this on printers and scanners. This has mostly been replaced with USB.

DIN 6

Standard: PS/2

Connector Name: DIN 6 (6 pin)

Sometimes called: PS/2 port, Mouse port, keyboard port, mini DIN 6

Number found on a system: 2

IRQ: 12 and 1

Max length: 100 ft

Quick recognition on a computer:

                This will look like a small round connector on the back of your PC. Usually color-coded green or purple. The green is for the mouse and the purple is for the keyboard. If they are not color-coded, look close to the connector for an indicator or look it up in the owner’s manual. Or go by the rule that the mouse is the one on the inside of the PC. If you do attach the wrong connector and start up the PC you will get a "beep" (if the internal speaker is still connected) and an error message ("No keyboard present").

Normally seen on: This is used for mice and keyboards

DIN 5

Connector Name: DIN 5

Transfer mode: N/A

Sometimes called: old keyboard connector

Number found on a system: 1

IRQ: 1

Quick recognition: On computer: On the keyboard cable this is a larger round connector with bigger pins arranged in a circular fashion. On some older motherboards, this may be the only built-on connector. It is also considered out-of-date. It was replaced by the PS/2 stile connector, which in turn is being phased out by USB.

Normally seen on: Only used on keyboards.

USB 1.1

Standard: USB 1.1 (by USB-IF)

Connector Name: USB A/B

Transfer mode: Asynchronous

Number found on a system: 2-5

Maximum number of Devices: 127

IRQ: 11

Max length: 3-5 meters

Max data rate: 12 Mbit/sec (1.5 MB/sec)

Power: 2.5w

Quick recognition on a computer:

 On the computer these look like thin rectangular slots.

Cable Quick recognition:

                The cable has 2 male connectors; one on each side. The difference between the a and b standard is that the 2 power wires are not at the b end. You would see this on a printer that gets its power from the wall.

Normally seen on: Mice, keyboards, scanners, modems and other low-power peripheral devices. Even some hard drives can be powered by this low current. This can also be found on digital cameras and some camcorders to download the movies and pictures to your computer. Also you can get speakers that use this type of connector. This interface has all but replaced the serial port.

Features: To connect many devices, you can use a USB hub. This is a box that you connect into your computer through one of your USB ports and then you can plug many other devices into it. Also, the speed of each USB chain is shared between all devices on that chain. So the more devices you have operating at once, the slower they all will go.

 *WARNING* With enough force you can plug a USB connector in upside-down. This will kill your motherboard (BOOM) or PCI card. Never force anything on your computer!!!!

USB 2

Standard: USB 2 (by USB-IF)

Connector Name: USB

Transfer mode: Asynchronous

Sometimes called: USB 2

Number found on a system: Still being determined

IRQ: 11

Power: 2.5w

 USB 2 is really just an upgrade in speed from USB 1.1. So everything is the same, just faster. You can use the same cables but you do need a new hub. The old hub will work, but it will only allow the USB 1.1 speed.

Firewire (IEEE-1394)

Standard: IEEE-1394

Connector Name: IEEE-1394 A B

Transfer mode: Asynchronous/Isosynchronous

Sometimes called: Firewire, IEEE-1394 or iLink (Apple computers has trademarked the term “Firewire.” So, if you see it called that, someone is paying for that ability. iLink is what Sony calls IEEE-1394).

Number found on a system: 2

Max length: 4.5m (between devices)

Max data rate: 100Mbps, 200Mbps, 400Mbps (12.5MB/sec 255MB/sec 500MB/sec). Most computers support 400Mbps but most devices are only 200Mbps

Max # of devices: 63

Quick recognition: This looks like a USB cable with 2 corners cut out.

 On computer: Looks like a square with 2 corners filled in.

Normally seen on: You will see Firewire on high-end devices like high res. scanners, high res. printers, hard drives, CD-RW, DVD, DVD-R/W, Video cameras, etc.

Features: Some on the added features are that you do not need a PC to connect them together. You could conceivably have a video camera connected to a DVD-R and burn your movies without needing a computer connected to it. They can talk to one another without using up the bandwith to the computer and back. You can daisy chain them together so there is no need for a hub as in USB. Also there is more power supplied. So, for example, you have enough to have a hard disk drive running without power coming from the wall. Some companies have set it up so you can connect an MP3 player to your computer using IEEE-1394 and transfer the data plus recharge the player's internal batteries off the firewire cable.

Video

 In this section we are not so worried about things like transfer rates and IRQs. The monitor will only refresh so fast and IRQs would affect your video board not your monitor. The point of this part is so that you can intelligently find and talk about these.

Standard: VGA

Connector Name: DB-15

Quick recognition ona computer:

                This is our old standby and by far the most common of our video connectors. It is easy to find. It is the only small three-rowed DB connector we will find on a PC. It is usually away from the other connectors because it is on a replaceable card. There are, however, motherboards that do have video built in. If so, then this connector will be close to the other connectors.

Power

                                                                                     

                The power connector is almost completely standard. This looks almost exactly like an extension cord with the exception of the ground being a slot instead of a round hole. Not much more to say.

                Make sure that the power switch on the back of your computer is set for the correct voltage (115 or 230) for your location.

 Be careful with laptops and some newer Apple Macintosh computers that may have different looking power connectors on the computer.

Minijack

Connector Name: 1/8 Minijack

Sometimes called: headphone jack

Number found on a system: 1-5

Quick recognition: This the same jack that you have been plugging into your walkman for years. It is a small pointed metal plug with one or two plastic bands imbedded in it.

 On computer: These can be found on the front on most CD-ROM and CD writers. On some CD readers and writers, you can plug a pair of headphones in and play audio CDs independently of the computer. You will also find these on the back side on the PC. If you have a sound card, there will be 3 or more. One for your speakers (this is usually lime green). If it is not color-coded, then consult the owner’s manual that comes with the sound card, motherboard, or PC. The other minijack is the sound-in connector. This is for connecting a microphone or other device that can deliver sound to your PC. This is color coded pink. There is one more plug that goes with this set--the line-in port. It has many different uses.

Normally seen on: Any PC with sound. The male end you will find on any set of speakers or set of headphones.

Joystick

 Male and female

 They come on most sound cards. It is a DA-15 port female on the PC and male on the device. This port on the PC will usually be colored gold. This is quickly being replaced by USB. Adapters are available to convert from the DA-15 to USB.

Networking:

Telephone cable

 RJ-11 is a common telephone cable.

The end is called an RJ-11 connector and the cable is called category 1 (Cat 1).

Ethernet cable

Standard: Connectors EIA/TIA 568a/b Cables Category 3, 4, 5 or 5e

Connector Name: RJ-45

Transfer mode: Serial

Sometimes called: Unshielded twisted pair (UTP) Shielded twisted pair (STP just UTP with some more shielding), 10BaseT, 100BaseT, 1000BaseT. Crossover cable

Number found on a system: 1 (sometimes more)

IRQ: Would be assigned to the Network interface card.

Max length: 100 meters (328 ft.)

Min length: 1 Meter (3 ft.)

Max data rate: 10/100/1000 Mbp/sec

Quick recognition on a computer:

 On computer: On the computer it looks like an over-sized telephone jack.

Normally seen on: Networking equipment for connecting 2 computers.

Tidbit: The A and B standard are very important to look for. If you have a cable that has never worked, look at the colors at the end. If they match, they are a straight-through cable. This is used for connecting dissimilar devices together i.e.… a PC to a Hub or a switch to a router. But you want to use a crossover cable for like devices i.e.… PC to PC, switch to switch, or router to router.

 *Warning* 80% of all network problems are caused by this little cable. If you can't get the network to work, check the cable before you go and start changing the setting.

                There is also a Plenum-grade Ethernet cable. This is a cable that is necessary for fire code. The issue is that if there is a fire and the PVC outer coating of non-Plenum grade cable catches on fire, it will release deadly gasses. In that case, if you have an enterprise grade network where you have literally thousands of these cables running through the walls, this can cause deadly results in a fire. Before wiring a building, check with the Fire Marshall about needing this cable.

SCSI

Connector Name: DB25, IDC50, Centronics 50, HDI30, DB50, HPDB50, HPDB68, HP Centronics 60, HP Centronics 68, SCA 80-Pin, and VHDCI68

Number found on a system: SCSI devices can be daisy chained, so the number connected to a system will vary

Max length: 1.5 meters to 25 meters depending on the type

Max data rate: 360 MB/sec max

Quick recognition: This is a big connector

On computer: This is the biggest connector you will see on a system

Normally seen on: Hard drives, CD-ROM drives, tape drives, scanners etc.

 50 Pin Centronics: This is connector is at the device end of some peripherals

 25 Pin D Sub: This one you have to look out for. You can plug a parallel connector into this and they will match up perfectly. But this is found on an Apple Macintosh. To help you out, you will not find a parallel connector on a Mac making this easy. If you are working on a Mac, it is a SCSI interface not a parallel connector.

 DB-50: This is a rare connector that has 3 rows of pins. It was used on HP and DEC computers. It is not very common.

 50 Pin MicroD (High Density): This is a connector that has 2 rows of squared off holes. It is used on 8-bit fast SCSI.

 68 Pin MicroD: This looks like the 50 Pin MicroD but longer and with more pins. This interface is used on all SCSI Wide connectors.

 It is beyond the scope of this paper to discuss ALL of SCSI. I just want to focus on recognizing these connectors. Most times you will not see SCSI on a PC. But this is the standard on most servers as it is fast - Up to 360MB/sec. This is a Gigabyte every 3 sec. Wow that is fast! SCSI has grown up as a technology and it has many implementations from SCSI-1, SCSI ultra wide, SCSI-2, SCSI-3, SCSI 160, SCSI 360 and more.

Thank You

1.2 Power Supplies

Contents:

§  Introduction

§  Voltage Switch

§  Wattage

§  Power Connectors

§  Laptop Power

§  Installation/Removal

§  Troubleshooting

Introduction:

A computer's power supply converts electricity received from a wall outlet (120V AC in the U.S.A.) into DC current amounts that are needed by the various components of the system. The back of the power supply has a plug for the cord that goes to the wall outlet. There are 2 different types of power supplies that correspond to 2 different types of motherboards, and hence, case designs.

Voltage Switch:

                Most power supplies have a switch on the back that sets the power supply to 115 or 230 volts (for European countries). Setting this switch to 230 in the U.S. won't damage anything, but the PC probably won't boot, or will shut down in the process. Setting this switch to 115 volts in Europe, will fry the power supply and possibly other components in the computer. Make sure the switch is in the correct position if there is one.

Wattage:

                Every device in a PC uses power which means that you need to have a power supply with enough wattage to run the system. If you have a 250 Watt power supply for a server with 10 hard drives, there are going to be problems. In fact, it may not boot up all the way. Power supplies for new computers are almost always capable of handling normal loads. If you are going to add a ton of drives or new devices to a system, that is when you might consider upgrading the power supply.

Power Connectors:

                For most current PCs the ATX power supply is the standard. There are slight variations such as the 12v and 12v 2.0, but for the most part power supplies for desktops are pretty standardized, although newer BTX power supplies are a different size and shape than the ATX type. Power supplies offer 12, 5 and 3.3 volt currents to power the various electronics in a computer. This is done via power cables coming out of the power supply. Below are some of the common power connector types.

P1 Power Connector - ATX power supplies use a single 20 or 24 pin (on newer versions) to connect to the system board. Some motherboards require an additional 4, 6, or 8 pin auxiliary power connector. Power connectors are keyed to make sure that the connector is plugged in properly.

SATA Connectors - SATA hard drives use a special 15 pin power connector. This connector supports 3.3, 5, and 12 volt devices. Make sure your power supply has one of these or you can get a molex to SATA adapter if it doesn't.

Molex Connectors - These connectors are used for connecting IDE hard drives, DVD and CD drives, and other devices that require 5 or 12 volts of power. These are keyed to prevent plugging them in upside-down, however, it is possible to do and will cause serious problems/damage to the system.

Mini Connectors - These connectors also supply 5 or 12 volts, but are basically only used to connect floppy drives. These are even easier to plug in upside-down.

Laptop Power:

                Laptops and portables utilize an external power supply and rechargeable battery system. Batteries were typically nickel-cadmium, but newer techologies have introduced nickel metal-hydride and lithium-ion batteries that provide extended life and shorter recharge times. Lithium batteries are also used to power a computer's CMOS ROM.

Installation/Removal

 To remove a power supply from a PC, follow these steps:

Unplug the computer from the wall

Disconnect all of the internal power connections (i.e. CD Rom, Motherboard, hard disk, etc)

Remove the 4 retaining screws

Pull power supply out of the computer

 Repeat these steps in opposite order to install a power supply

Troubleshooting:

                Power supply problems can be some of the most difficult to diagnose particularly when the problem is intermittent. Often the fuse in a power supply will blow and you may actually hear a pop and/or smell smoke. Oftentimes, if you shake the power supply, you will hear a rattle. This means it is dead and needs to be replaced. You should not open the power supply and replace the fuse or try to fix any other part of it. There are capacitors inside that hold a charge and power supplies are way too inexpensive to risk injury on.

Intermittent problems can display a wide range of symptoms from not booting correctly, to errors, to locking up after a period of use. It is a good idea to keep a spare on hand for troubleshooting.

ATX Power/Cooling:  ATX Chassis:

Why the computer/fan does not turn on after I flipped the power switch to ON located on the ATX power supply?

                ATX power supply is different from AT power supply. It depends a logic circuit on the motherboard to turn it on. Once you flipped the power switch on the ATX power supply to on (some ATX power supplies do not even have such a switch), the ATX power supply sends a 5V 720MA current to the motherboard through pin 9 on the power connector. That current is for WOL (Wake-up On Lan) and power on circuits. There is a power-on jumper on the motherboard that connects to the pushbutton located in front of ATX case. When the pushbutton is pressed, it sends a signal to the mothboard, which in turn notifies the ATX power supply to turn on the full power. The location of the power-on jumper on the motherboard is manufacture dependent. You will need to read your motherboard manual to locate that jumper. At any event, do not try to manually jump-start the power supply without attaching motherboard. Since the power supply is expecting certain sensing circuit feedback to regulate the output voltage, munaully starting it without attaching it to the motherboard could cause damage to the power supply.

How do I test if the power supply is bad?

Warning - This test is for those who have extensive electronics training. Do not try this if you do not have extensive electronics training. Make sure there is enough load connected to the power supply before testing (at least motherboard and one hard drive)!

                ATX power connector is layout like above. 5VSB constantly provides 5V power to the connector through pin 9. If you have a voltmeter, while the power supply fan does not turn on, you could identify which pin is pin 9. Normally there is a clip on the connector between pin 15 and 16. If you can identify pin 14, which is power-on pin, you can using a piece of wire short the pin 14 and 15. If you power supply has power connected to it and power switch on the power supply is on, you will see the fan is turnning by now. Otherwise, your power supply may have problem.

What kind of power supply do I need to buy for AMD and Pentium 4?

                To support the faster CPU speed, both AMD and Intel have new requirement to the power supply to be used for their new processors. The most important factor for selecting the correct power supply is the output DC current for the processors and motherboard. For most AMD processors, the 5V supply must provide at least 18A. For the new Intel P4 processors, the 5V must provide at least 20 amperes. Both AMD and Intel P4 also require the +5V standby can provide at least 720mA or more. Without suffcient 5V and 12V current from the power supply, the system may become unstable/unreliable and may experience difficulty to power up the system. The minimum wattage required for a Intel P4 system is 230W.

 For server motherboard stability, Intel recently also developed the new power supply requirement for server board. The power supplies for the new Intel P4 server boards recommended to have following connectors:

The purpose of those connectors are for the current to go directly from power supply to the point where the current draw the most, thus improve the server stability.

How to tell a power supply's real wattage?

 Many cutomers emailed us asking this question. It is difficult to tell by looking or reading the labels. To be accurate, you will need an instrument to measure it. Roughly, you might be able to tell by the weight. Yes, by the weight! Faked 300W power supply has the similar weight as the 250W power supply. Real 300W poewr supply is much heavier than the 250W power supply, due to the heatsink is larger, and components must be able to handle larger current. To the manufacture, it will cost close to $28 USD marterial to make a 300W power supply, not including the labor and shipping. If someone selling a computer case including a 300W power supply totally less than $30, you know that is not real!

What is the difference between the ATX and the microATX (uATX) chassis?

                Full size ATX motherboards may be integrated with a chassis that complies with the ATX 2.01 or later specification.

                The microATX specification was released in January 1998 and is a derivative of the ATX2.01 specification. The purpose behind drafting this specification was to provide a lower cost platform solution that was backward compatible to standard ATX2.01.

 The microATX motherboard may be integrated into either a full size ATX or a microATX chassis that meets the ATX2.01 or later specification. The full size ATX motherboard may be integrated into a full size ATX chassis and may not be integrated into a microATX chassis. More detailed information on both the ATX and microATX chassis is available on their dedicated web sites at http://www.teleport.com/~atx and http://www.teleport.com/~microatx.

Note: A thorough evaluation needs to be performed by the system manufacturer on the ATX or microATX (uATX) chassis chosen. The system manufacturer is responsible for ensuring that there is adequate airflow and cooling for the processor. Our cases are designed with all these possible situations in mind, so the cooling is never a problem. We also recommend all the systems installing the optional cooling fan so that it will never have overheat problem in the hot summer.

Do I need a special chassis for microATX motherboards?

                The microATX motherboards can be integrated into a micro tower chassis and powered by lower wattage power supplies. The microATX motherboards can also be integrated into the full ATX 2.01 (or later) compliant chassis like the one being sold on our web site.

 Power Supply:

What special power supply requirements does the ATX motherboard have?

                The ATX motherboard is designed to operate with at least a 145 Watt power supply for typical system configurations. A higher-wattage supply may be required for heavily-loaded configurations. The power supply must provide +5VSB (voltage stand by) with 720mA of current (see the ATX2.01 or later specification). If the power supply does not supply sufficient current, some system configurations with the motherboard may not power up. Additionally, if the power supply can not supply sufficient current, and does not have overload protection, the power supply may be damaged. That is why we pay close attention to the manufacture process of the power supply in our case so that it would not be a problem of the end users. If you are using AMD CPU chip, it is recommended to use AMD Certified power supply.

What power supply requirements does the ATX motherboard have if a WOL (Wake on LAN*) capable Network Interface Card (NIC) is installed?

                A power supply that provides at least 720mA on 5VSB must be used when building a WOL capable system.

 If your power supply is not capable of meeting the 720 mA current requirement, your system may not power up. Also you could experience damage to your power supply if it does not have any over-current protection. Please contact your system integrator to see if your power supply meets the 720 mA current requirement. All of our power supplies are meet or exceed the ATX 2.01 requirement, so that it is never a problem for our customers.

 If you are using a WOL capable NIC but are not using the WOL capability you can remove the cable from the NIC to the WOL header on the motherboard. This will prevent the NIC from drawing additional current from the 5VSB.

System Airflow

                This section explains why our cases are better than many the "fancy" looking ones out there. The heat problem with those fancy ones will kill their motherboards. Our case will allow heat exhausted from the case easier. In addition, we always offer the system fan option to allow the system running in the room temperature without special air conditioning cooling need.

System airflow is determined by:

 Chassis design

 Chassis size

 Location of chassis air intake and intake vents

 Power supply fan capacity and venting

 Location of processor(s) slots

 Placement of add-in cards and cables

System integrators must ensure airflow through the system to allow the fan heat sink to work effectively. Proper attention to airflow when selecting subassemblies and building PCs is important for good thermal management and reliable system operation.

Integrators use three basic motherboard-chassis-power supply form factors for desktop systems: ATX, microATX, and the older Baby AT form factor.

Intel recommends the use of ATX form factor motherboards and chassis for the boxed Pentium II Processor. The ATX form factor simplifies assembly and upgrading of PCs, while improving the consistency of airflow to the processor. With regard to thermal management, ATX components differ from Baby AT components in that the processor slot is located close to the power supply, rather than to the front panel of the chassis. Power supplies that blow air out of the chassis provide proper airflow for active fan heatsinks. The boxed processor's active fan heatsink cools the processor much more effectively when combined with an exhausting power supply fan. Because of this, the airflow in systems using the boxed processor should flow from the front of the chassis, directly across the motherboard and processor, and out of the power supply exhaust vents. Figure 1 shows proper airflow through an ATX system to achieve the most effective cooling for a boxed processor with an active fan heatsink. For the boxed Pentium II Processor, chassis that conform to the ATX Specification Revision 2.01 or later are highly recommended.

Figure 1. System Airflow through ATX Tower Chassis Optimized for the Boxed Processor with an Active Fan Heat sink

MicroATX chassis differ from most ATX chassis in that the power supply locations vary and they may use SFX or ATX power supplies. Thermal management improvements that apply to ATX chassis will also apply to microATX. Our Mini Tower case fit in the category of microATX and satisfy Intel's spec. Our middle and full ATX case all tested and satisfy the Intel ATX 2.01/2.03 spec.

The following is a list of guidelines to be used when integrating a system. Specific mention of Baby AT, ATX, or microATX components is made where necessary.

Provide sufficient air vents: Systems must have adequate air vents in addition to a fan. Chassis vents must be fully functional. Integrators should be careful not to select chassis that contain cosmetic vents only. Proper location of vents results in a good stream of air flowing over the processor. For Baby AT systems, intake vents on the front of the chassis allow air to flow over the processor. For ATX and microATX systems, exhaust vents in the chassis allow air already forced over the processor (by the power supply) to flow out of the chassis.

Power supply air flow direction: It is important to choose a power supply with a fan that moves air in the proper direction. For Baby AT systems, the power supply fan acts as an exhaust fan, venting system air outside the chassis.

Power supply fan strength: For some chassis that are running too warm, changing to a power supply with a stronger fan can greatly improve airflow. If that is not an option, add an additional system fan.

System fan--should it be used?

 Some chassis may contain a system fan to assist airflow. A system fan is typically used with passive heatsinks. With fan heatsinks, however, a system fan can have mixed results. Thermal testing both with a system fan and without the fan will reveal which configuration is best for a specific chassis. When a fan heatsink is used on the processor, changing to a power supply with a stronger fan is usually a better choice than adding a system fan.

System fan airflow direction: When using a system fan, ensure that it moves air in the same direction as the overall system airflow. For example, a system fan in a Baby AT system should act as an intake fan, pulling in additional air from the front chassis vents.

Protect Against Hot Spots: A system may have a strong airflow, but still contain "hot spots." Hot spots are areas within the chassis that are significantly warmer than the rest of the chassis air. Such areas can be created by improper positioning of the exhaust fan, adapter cards, cables, or chassis brackets and subassemblies blocking the airflow within the system. To avoid hot spots, place exhaust fans as needed, reposition full-length adapter cards or use half-length cards, reroute and tie cables, and ensure space is provided around and over the processor.

Keep Power On or Off?

                People debate a lot on this topic. Lets take a look what is good for turning system off everyday. First, that saves electricity and saves the environment; Secondly, it reduces the wear on the fans, hard disk and other moving parts, reduces the electronics components aging. What is good about keep computer on all the time, then? It can save time, it is on whenever you like to use it.

 If your computer stays in a home or an office that maintaining close to constant temperature, preferably under 80 degrees, there is no harm done to turn it off whenever you finish using it. However, if the computer stays in a place that temperature varies a lot, like in a warehouse that could go up to 110 degree during the day and goes down to 60 degree in the night, it is better to keep the computer up and running. In that kind of situation, the temperature creates a lot of tension on the electronics components in the power supply or motherboard, having the computer on all the time helps maintaining the components not being broken apart by the mechanical force(heat expansion and cold contraction).

 If you decide to keep your computer on all the time, make sure check all the fans every 3 to six months. Fans tend to wear out quickly in that kind of situation. If fan locked up and not replaced, the power supply or motherboard will overheat and quit working shortly after. It is better to replace the fan before it worn out completely. Choosing ball bearing fans and industrial chassis will also help the system last longer.

Thank You

1.3 Motherboards

Contents:

§  Form Factors and Chipsets

§  Motherboard Installation

§  Expansion Busses

§  System Resources

§  The BIOS and CMOS

Form Factors and Chipsets

                A motherboard may also be called a planar board, system board, or main board. There are various types of motherboards that differ depending on the type of case that they fit in and the type of processor that they host. The form factor of the motherboard describes its general shape, what sorts of cases and power supplies it can use and its physical layout. A company can make 2 motherboards that have basically the same functionality but that use a different form factor and the only real differences will be the physical layout of the board and the position of the components. Common form factors have included AT, Baby AT, ATX, Mini ATX, LPX, Mini LPX and NLX. The table below contains more information:

 NOTE: Laptop motherboards tend to be proprietary to the model for which they are designed.

 Currently, the ATX form factor is the most widely used for new PCs. The BTX standard provides better airflow and cooling, specifically the thermal unit which blows hot air from the CPU directly out of the case. At this time, it is unknown if this form factor will take off or fade into oblivion.

 When first looking at a motherboard, you should see that the top side of the motherboard contains ports used for connecting various peripherals. Peripherals are composed of input and output devices including the mouse, keyboard, monitor, speakers, printer, etc. On the main face of the motherboard, we have our processor socket, RAM slots, FDD and HDD controllers, expansion slots and other features. Motherboards also contain configurable jumpers and possibly even DIP switches(typically on older models). These jumpers use BERG pins and a small connector that slides onto the pins to designate "on". BERG connectors are also used to connect the front panel LEDs and switches to the board. Below is a graphic that shows some of the common features of an ATX motherboard.

ATX System Board

                Now that we have looked at form factors, we next need to discuss chipsets. The chipset of a motherboard defines the type of processor(s) that the motherboard can take, the type and size of RAM, and many other capabilities and features of the motherboard. For the most part, the chipset will also determine the configuration of USB and firewire ports, whether or not there is onboard sound, video, networking, and other features. Motherboard manufacturers may choose to make alterations outside the specifications of the chipset. Chipsets are made up of 2 main chips which are known as Northbridge and Southbridge. The Northbridge's duties are typically to facilitate the relationship between the processor and RAM and handle video, while the Southbridge handles storage and expansion devices. Popular chipset manufacturers include Intel, AMD, VIA technologies, and NVIDIA.

                As a technician, you will need to know how to put together a computer that meets a customer's needs. For starters, you need to make sure that you have the right case for your motherboard, a processor with the right socket and speed for your motherboard, and the features that your customer wants. If the motherboard doesn't offer onboard sound and video, networking, etc., you will need to get expansion cards for these, or find a motherboard that does include these features. Similarly, when replacing a bad motherboard, you need to make sure that it is compatible with the rest of the system. If the customer frequently uses USB flash drives and other USB devices, you might want to get a system that offers front side USB ports, or a USB hub. If they are still using dial-up, you should be aware that many new systems no longer offer on board modems. You need to make sure that the case you choose fits the customer's environment. If the customer's desk only has 18 inches of clearance, then it wouldn't be a good idea to get a full tower case. The list could go on and on, but you probably get the idea.

Motherboard Installation

                When working with internal components on a computer, don't forget to wear your anti-static wrist strap. Below are the steps for installing a motherboard.

Lay the case on its side with the open side facing up.

Insert the little risers with screw holes on one end into the holes on the back inside of the case. These little risers are called standouts and are used to elevate the motherboard off the back wall of the case. Make sure that the locations you have placed the standouts align with the screw holes on the motherboard. Some cases come with the standouts already installed.

Next, you might choose to install the RAM and CPU beforehand, or go ahead and put the motherboard in first.

Insert the motherboard into the case and screw it into the standouts.

If you have not already, install the CPU, CPU fan, and RAM.

Connect the power from the power supply to the motherboard.

Connect a monitor and boot the system. If you see the BIOS splash screen, you are probably in good shape.

Connect the wires for items such as the power button, reset button, power LED, system speaker, hard drive activity LED, front side USB, etc. These BERG connectors have a positive and negative side. If a particular item is not working, plug it in the other way.

Connect all drives and periperals.

Expansion Busses

                As we all know, computers aren't "what you see is what you get" systems. Since their inception, they have provided a way to add functionality through the use of expansion slots to which expansion cards can be added. In order to accomodate expansion cards from various manufacturers, they needed to have a standard for them to adhere to, and thus, the expansion bus was born. The expansion bus provided a method for standardizing the physical characteristics and speed. With regards to speed, it should be noted that the expansion bus runs at a much slower speed than the system bus. Below is a look at the history of expansion busses.

                Currently, most new motherboards contain AGP, PCI, PCI-X and/or PCIe slots. PCI has dominated the market for some time and continues to do so. In addition to its faster speed of 33MHZ, one of the biggest selling points was its ability to self configure devices which was a beginning step in the emergence of Plug-and-Play. Now, new variations of PCI are being adopted such as PCI-X and PCIe. The main difference between PCI-X and the original PCI standard is speed. PCI-X offers 4 speed options: PCI-X 66, PCI-X 133, PCI-X 266, PCI-X 533.

 PCIe is the latest and greatest technology and is a dramatic change in that it uses a full-duplex point-to-point serial (as opposed to the traditional parallel) connection directly to the Northbridge. This connection is known as a "link", and is built up from a collection of 1 or more lanes. All devices must minimally support a single-lane (x1) link. Devices may optionally support wider links composed of 2, 4, 8, 12, 16, or 32 lanes. The more lanes, the wider the PCIe slot and the faster the speeds. A PCIe card will physically fit (and work correctly) in any slot that is at least as large as it is (e.g. an x1 card will work in an x4 or x16 slot). PCIe 2.0 can theoretically achieve speeds of 16GBps in both directions when having 32 lanes.

System Resources

                In previous versions of this study guide, this is where we would list tables of IRQs, I/O addresses, etc., that you would need to memorize. Now that the new exam no longer covers Windows 9x or Windows ME, we don't believe you will be tested on this information anymore. It is still probably important to know the following.

 Devices in a computer utilize 4 categories of system resources as follows:

IRQ - The IRQ (interrupt request) value is an assigned location where the computer can expect a particular device to interrupt it when the device sends the computer signals about its operation.

I/O Address - Input/output addresses are resources used by virtually every device in a computer and represent locations in memory that are designated for use by various devices to exchange information between themselves and the rest of the PC. No devices share the same I/O address.

DMA - Direct Memory Access channels allow hardware devices (like sound cards or keyboards) to access the main memory without involving the CPU. This frees up CPU resources for other tasks.

Memory Address - In some situations an expansion card will have onboard RAM or ROM that needs to borrow memory from the system RAM so that the CPU can access it.

 In the old days, system resources had to be manually configured and problems with IRQ and I/O conflicts were frequent. This is no longer an issue as these things have been completely automated.

The BIOS and CMOS

                                 BIOS stands for Basic Input/Output System and is a collection of small software programs that allow a CPU to talk to the hardware components of the PC. The BIOS resides on a system ROM chip categorized as firmware. Traditionally you could not make changes to ROM chips, however, all newer ones are flash ROM which means that they can be updated. BIOS services are accessed using software interrupts, which are similar to the hardware interrupts except that they are generated inside the processor by programs instead of being generated outside the processor by hardware devices.

 BIOS routines begin when the computer is booted and are mad up of 3 main operations. Processor manufacturers program processors to always look in the same place in the system BIOS ROM for the start of the BIOS boot program. This is normally located at FFFF0h - right at the end of the system memory.

 First, the Power On Self Tests (POST) are conducted. These tests verify that the system is operating correctly and will display an error message and/or output a series of beeps known as beep codes which vary depending on the BIOS manufacturer. If you don't have your system speaker connected, you will not hear the beep codes. The text and beep errors generated by the BIOS can be cryptic and sometimes a better solution is to use a Post Card. A post card plugs into an expansion slot and will generate a numerical code designating the component that was being tested when the failure occurred.

 Second, is initialization in which the BIOS looks for the video card. In particular, it looks for the video card's built in BIOS program and runs it. The BIOS then looks for other devices' ROMs to see if any of them have BIOSes and they are executed as well.

 Third, is to initiate the boot process. The BIOS looks for boot information that is contained in file called the master boot record (MBR) at the first sector on the disk. If it is searching a floppy disk, it looks at the same address on the floppy disk for a volume boot sector. Once an acceptable boot record is found the operating system is loaded which takes over control of the computer.

 People often use the terms BIOS and CMOS interchangeably, but they are actually completely different. CMOS stands for Complimentary Metal Oxide Semiconductor and in the old days was a completely separate chip on the motherboard. Nowadays, it is often built into the southbridge. While the BIOS contains basic information that allows communication between the CPU and hardware, it cannot take into account all of the specific features and brands of hardware available. This is where the CMOS comes in. The CMOS setup program (AKA CMOS Setup Utility) is a program that allows us to access the information and settings stored on the CMOS chip. CMOS setup can be accessed by pressing a key or certain combination of keys right after booting the computer. The key or keys varies by BIOS manufacturer.

 Once in the CMOS setup utility, you can view and change a wide variety of features for your hardware. These options will vary widely depending on your system, however, below are some of the common tasks you can perform:

Change the CPU voltage and multiplier. This is known as overclocking.

Change the system's date and time.

View and change floppy and hard drive settings.

Change the boot order of the PC. This is handy when you are installing an operating system with a bootable CD-ROM and need to change the boot order to boot from the CD-ROM drive first.

Enable, disable, and configure settings for parallel ports, serial ports, USB, etc.

Configure power management.

Configure a password to access CMOS setup. This can usually be cleared with jumper settings on the motherboard.

 CMOS is also responsible for managing the system's date and time information as well. CMOS uses a battery to store this and the other configuration information. In newer systems, if the battery dies, CMOS is reset to factory default.

Thank you

1.4 Processors

Contents:

§  Introduction

§  Speed

§  Voltage

§  CPU Terms

§  Chip Characteristics

§  Bus Sizes of CPUs

§  Current Trends

§  Installing a Processor

§  Cooling

Introduction:

The processor, also known as a microprocessor and the CPU, can be thought of as the brains of the system and is responsible for executing software commands and performing calculation functions. There are basically 2 CPU manufacturers today - Intel and AMD. Their processors are not interchangeable meaning that if you buy an AMD CPU, you must have a motherboard that supports AMD CPUs and vice versa.

Speed:

 A CPU's capabilities are defined by their "instruction set" which are lines of code that are passed back and forth over the external data bus. CPUs are rated by clock speed - this is the speed is the maximum speed that the CPU can operate at. The motherboard has a system crystal soldered to it that sends a pulse out at a given speed that is received by the CPU. This is referred to as the system bus speed. The CPU will normally operate at the system bus speed even if it can handle faster speeds. With most CPUs it is possible to tell the clock chip to operate to multiply the system pulse to go faster than the CPU's designed speed. This is called overclocking which is a risky option that can lead to hardware failure.

                Now all processors are capable of operating at much faster speeds than the chips on the motherboard. To deal with this, CPU manufacturers began creating clock-multiplying CPUs which can operate at faster speeds for internal functions (they still communicate at slower speeds over the address bus and external data bus). The external speed, also known as the front side bus or FSB, is multiplied by the multiplier to give the internal CPU speed. For example, if the FSB has a clock speed of 133 MHz and the CPU multiplier is 10x, then the processor would run at 1.33 GHz.

Voltage:

 The transistors on a motherboard use 5 volts of electricity, however, CPUs have varying voltages. Decreasing the voltage allows manufacturers to use smaller transistors, and hence, fit more of them into the CPU. To deal with the varying voltages, modern motherboards have an integrated Voltage Regulator Module (VRM) that adjusts the voltage level that the CPU receives from the system.

CPU Terms:

Registers - Registers are special storage locations located inside the CPU. The data contained here can be accessed much quicker than the data contained in other memory locations, such as the RAM (random-access memory) and the ROM (read-only memory). Registers in different parts of the CPU are used for different functions. In the control unit, the registers are used to store the computer's current instructions and the operands (this is merely a fancy term for data that is being operated on by the CPU). Meanwhile, the registers found in the ALU, called accumulators, are used to store the results of the arithmetic or logical operations.

Address Bus:

The address bus is a collection of wires connecting the CPU with main memory that is used to identify particular locations (addresses) in main memory. The width of the address bus (that is, the number of wires) determines how many unique memory locations can be addressed.

Arithmetic/Logic Unit (ALU) –

The ALU is the part of the CPU that does the actual computing and calculations sent to it by programs.

Cache

Small memories on or close to the CPU chip can be made faster than the much larger main memory. Most CPUs since the 1980s have used one or more caches, and modern general-purpose CPUs inside personal computers may have as many as half a dozen, each specialized to a different part of the problem of executing programs. It is very similar to the concept of a browser cache that stores data from visited web sites making subsequent visits to those sites load faster.

Hyperthreading –

The Intel Pentium 4 introduced hyperthreading which allows each pipeline to run more than one thread at a time. This essentially tricks the system into thinking that there are 2 processors. Hyperthreading only works with operating systems and applications that support it.

Chip Characteristics:

 Note: You do not need to memorize the data in the following tables. It is here for reference purposes.

With the Pentium MMX processors, 57 multimedia specific instructions were added to increase multimedia performance and increased the L1 cache size to 32KB.

The Pentium Pro added Dynamic Execution and increase L2 cache to 512KB.

The Pentium II had integrated MMX technology and used a new Single Edge Contact Cartridge(SEC).

The Pentium III provided increased processor speeds, a 100mhz front size bus speed and increased L2 cache to 512KB.

The Celeron processors are less expensive but only have a 66mhz bus and 128KB L2 cache.

The Pentium IV introduced a number of graphics enhancements. 2 versions were made - The first was a 423-pin PGA package with 256 KB L2 cache. The second version offers a 478-pin PGA package with 512 KB of L2 cache.

Intel Xeon processors are higher-end and based on their Pentium II, III and IV counterparts.

Bus Sizes of CPUs

While Intel holds the majority of the processor market share, companies such as AMD have been producing clones based on the X86 architecture. The table below outlines the various socket/slot types and the processors that they support.

Current Trends:

 A few years ago, Intel was the first to introduce a 64-bit processor (Itanium II). Since that time, 64 bit processors have become the standard. Clock speeds hit a brick wall at around 4GHz a few years back which forced CPU manufacturers to find new ways to squeeze more performance out of their chips. Intel and AMD both released "dual core" processors that are essentially 2 processors in one. The Intel Pentium D was basically 2 Pentium 4 processors together with their own cache. AMD launched a similar product called the AMD Athlon 64 X2 processor, however, the L1 cache was shared by the processors. Shortly after, Intel abandoned their Pentium line of processors which gave way to the Intel Core series. Core processors come in "Solo" or "Duo" (dual core) versions. This line was followed by the Intel Core 2 architecture that comes in "Duo" or "Extreme" versions.

Installing a Processor

Before installing (or buying) a processor, you should make sure that your motherboard supports it. It is also very important to make sure that your motherboard uses the same package as your processor. In other words, a socket 775 processor (shown left) will not fit into a 478 socket. If you try to force it, you will likely bend the metal pins sticking out of the bottom of the processor. Typically, installation is as easy as placing the CPU in the socket and pushing down on the locking lever attached to the motherboard which can be seen on the left side of the image to the left. This lever is located on the side of the socket. Most CPUs and sockets are keyed so that you place it in the correct spot.

Cooling:

CPUs get very hot and the faster the CPU, the hotter it will get. This is why we need to attach a fan or newer cooling method such as a liquid cooling system. A typical cooling fan is pictured to the right. Before you install your fan, place a little bit of thermal compound on the top of the CPU. The fan will typically have clamps that lock onto the side of the socket on the motherboard. These can be difficult to install. Be patient and try not to damage your motherboard, especially when removing the fan. After securing the fan, you will need to plug in the power cable to the appropriate spot on your motherboard. See your motherboard manual for the location.

Thank You

1.5 Memory

Contents:

§  Introduction

§  Types of RAM

§  Physical Types

§  Important Terms

§  Installing RAM

§  Virtual Memory

Introduction:

RAM stands for "random access memory" and is volatile. When an application is launched, it is placed in RAM for faster access by the CPU. It is one of the main components that affects system performance. Over the years a variety of memory types have emerged including DIP, SIP, SIMM, DIMM and most recently RIMM.

Types of RAM:

Static RAM (SRAM) - SRAM doesn’t have to be constantly refreshed. Uses a lot of power. Used in old IBM XT machines and was limited to 256K per chip. This type of memory is no longer used and has been replaced by DRAM.

Dynamic RAM (DRAM) - DRAM uses capacitors instead of transistors and switches. Needs constant refreshing. This type of memory is still in use, however, has undergone upgrades such as the SDRAM and RDRAM varieties below.

Synchronous DRAM (SDRAM) - SDRAM is tied to the system clock which provides support for the faster bus speeds of modern computers. The speed of the memory that you install in a system must match or exceed the system speed in order to work. Installing RAM that is faster than the system speed will operate at the system speed. For example, if you put PC 133 RAM into a system that is running at 100 MHZ, the RAM would operate at the 100 MHz speed. You can sometimes mix speed ratings when installing multiple modules, however, it is not recommended because it can cause the system to lock up or not start at all.

Rambus DRAM (RDRAM) - RDRAM added support for even faster bus speeds and first surfaced around the time of the Pentium IV. RDRAM used RIMMS which required a heat spreader to be attached to the RIMM to deal with its increased heat levels. Unused slots on a RDRAM motherboard had to be terminated with a CRIMM in order to function. Due to the higher cost and the licensing fees that manufacturers had to pay to Rambus, RDRAM never took off.

Double Data Rate Synchronous DRAM (DDR SDRAM) - With the failure of RDRAM and increasing bus speeds, manufacturers still needed an upgrade to regular SDRAM and DDR SDRAM was born. Like RDRAM, DDR SDRAM increases performance by supporting 2 processes per clock cycle. DDR SDRAM utilizes 184 pin DIMMS for desktops and either 200 pin SO DIMMS or 172 pin micro-DIMMS for laptops. The naming convention for this type of memory is PCxxxx. It is calculated by taking the clock speed, doubling it (double data rate), and multiply it by 8 (the number of RAM chips on a stick). So if a module has a 200 MHz clock speed, the name would be PC3200. Like RDRAM, you must have 2 identical sticks of RAM installed as a pair. Unused slots do not need terminating though. Recently, DDR2 SDRAM was created. DDR2 clock doubles the input/output circuits on the chips, but does not actually increase the core speed of the RAM.

Windows RAM (WRAM) - Specifically designed to speed up graphical windows operations.

Video RAM (VRAM) - Uses a dual port access system to speed up video operations.

Physical Types:

Important Terms:

Double-sided RAM - Double-sided RAM is a type of memory which has its chips divided into two sides (called "ranks"), only one of which can be seen at a time by the computer. To use the second half of the storage available, the computer must switch to the second rank, and can no longer read or write to the first half until it switches back again. Single-sided RAM refers to a RAM expansion with a single "rank" of chips, which the computer can access all at once. The terms double-sided RAM and single-sided RAM have nothing to do with having physical chips on one or both sides, although that is a common misconception.

Parity RAM - RAM occasionally "misfires" and makes mistakes. For home users this isn't a big deal, but for mission critical applications it can be. Parity checking adds an extra bit to the data that the MCC uses for error detection. Parity RAM is unable to correct the errors and doesn't always catch them.

Error Correction Code RAM (ECC) - ECC RAM is a high-end type of memory that detects and corrects RAM errors. Due to the expense, this type of RAM is rare and only used in mission critical situations. The motherboard must support ECC in order for it to work.

Installing RAM:

Installing RAM is easy. The hardest part is making sure that you have the right kind and you should always check the motherboard manual for the specs. You should also try not to mix manufacturers, speeds, or capacity when buying multiple sticks or upgrading existing RAM. While it will most likely work, it is better not to do this in order to avoid problems.

 Once you have the right kind, intalling the memory stick is as simple as placing it in the slot on the motherboard. Make sure that you handle it from the top and avoid touching the contacts. You may have to push with some force to get it in and to get the tabs on either end of the slot (see image) to lock onto the notches in the ends of the stick, but don't push so hard that you damage the memory or the motherboard. If a memory stick is not going in, make sure it is the right kind - they are keyed so that only the right type of RAM will fit in the slot. In the image to the right, you can see a notch in the middle of the slot - this is the key. Once your RAM is installed, you can boot the computer and watch for the RAM count during startup to make sure that it is being recognized properly. If you miss that, you can always go into the Device Manager in Windows to see how much RAM the system sees.

Virtual Memory:

 Protected Mode became available with the 80286 and provided the ability to use Virtual Memory. Virtual Memory is the ability for the computer to use free hard drive space as extra memory. Excessive paging of the hard drive is usually a sign that the system needs more RAM.

Thank You

1.6 Storage

Contents:

§  Hard Drives

§  RAID

§  Hard Drive Installation

§  SCSI

§  Floppy Drives

§  CD ROM Drives

§  DVD Drives

§  Tape Drives

§  Flash Drives and Flash Cards

Hard Drives

Hard drives are magnetic storage devices that contain several discs inside called "Platters" that are attached to a spindle motor. The number of platters varies depending on the capacity of the drive. Platters are coated with a film of magnetically sensitive substance that is primarily made of iron oxide. Another important ingredient is a thin layer of cobalt alloy. The read/write heads are responsible for reading and writing to the platters and are attached to the head actuator which is in charge of moving the heads around the platters.

                The voice coil actuator is found in modern drives and assures that the heads are in proper position which ensures that the appropriate tracks are read. The guidance system used by the heads is called a servo. Its job is to position the head over the correct cylinder. The spindle motor is responsible for spinning the platters at a rate ranging from 3600 RPM to 10000 RPM depending on the drive. Heads typically have a coil of copper wire inside. Currents are passed through the wires which causes the surface underneath to become magnetized, creating 1 bit of data. The direction of the current passing through the wiring dictates the polarity of the magnetization, which creates a 0 or a 1. To read the data, the drive's electronics detect polarity differences.

 The disk's surface has tracks that are rings that are located next to each other. Each platter has the same number of tracks, and the tracks on the outside are larger than the tracks on the inner part of the surface. A track location that cuts across all platters is called a cylinder. Each cylinder is divided into sectors that are 512K in size. The size of the sector determines the amount of data that can be written, and the amount that will be wasted if only a few characters are in a record. A one byte record written to a sector occupies the entire track in that sector.

 Hard drive performance is measured as follows:

Access Time - This is a measure of the average time that it takes the drives R/W heads to access data on the drive.

Seek Time - This is the amount of time it takes for the drives head to move between cylinders and land on a particular track.

Data Transfer Rate - The megabytes per second(MBps) in which data is transferred between the drive and the system.

 There are several different type of interfaces that can be used including IDE, EIDE and SCSI. Each IDE interface can support up to 2 devices. IDE devices each contain their own integrated controllers, and so in order to maintain order on the channel, it is necessary to have some way of differentiating between the two devices. This is assigning each device either a master slave designation using jumpers on the drive, and then having the controller address commands and data to either one or the other. Another option is to set the jumpers to cable select. This means that the position of the drive on the cable will determine its status. If you are using two drives on a single channel, it is important to ensure that they are jumpered correctly. Making both drives the master, or both the slave, will most likely cause problems.

 CompTIA uses the terms ATA, IDE and EIDE interchangeably to refer to all non-SCSI devices. IDE Drives come in 2 types:

Parallel ATA - The older, but still widely used variety, that uses a 40-pin cable to connect to devices.

Serial ATA - A newer specification that offers a number of benefits including: Faster throughput, thinner 7-pin cable that promotes better airflow through the case, support for longer cables (nearly 40 inches long), and hot-swappable. In addition, there are no jumpers to worry about because each device connects to its own controller channel. There are 2 varieties of SATA. The 1.5Gb type has a throughput of 150MBps and the 3Gb type (sometimes called SATA II) runs at 300MBps. eSATA makes the SATA bus available for external devices.

                PIO and DMA are 2 different transfer modes and protocols that are used by hard drives to access the computer. Details of each are provided below:

PIO Mode - The Programmed I/O (PIO) mode is the older of the 2 methods for transferring data. This method uses the CPU to control the transfer of data between the system and hard drive. There are several different PIO modes that offer different speeds. These are shown in the table below:

DMA Mode - Direct Memory Access mode allows devices to transfer data to and from memory without using the CPU which reduces the overhead. PCI controllers use bus mastering to accomplish direct memory access. Below are tables which show the different DMA modes and their transfer rates:

DMA Mode

Ultra DMA - The maximum speed of multiword DMA mode 2 was 16.7 MB/s. As faster and faster hard drives were created the new Ultra DMA specification was needed. The table below shows the transfer rates:

                Drives that use Ultra DMA are typically referred to as "Ultra ATA/xx" where "xx" is the speed of the interface. For example, a drive that uses Ultra DMA mode 5 is referred to as ATA/100 because its throughput is 100 MBps.

Note: Both the hard disk, the system chipset and BIOS must support the mode in question.

RAID:

                Hard drives can be configured in a Redundant Array of Inexpensive Drives(RAID) configuration that is used for a variety of purposes including data recovery and increased read/write performance depending on the level of RAID employed. The RAID levels are as follows: RAID Level 0

                Disk striping will distribute data across 2-32 hard disks. This provides the fastest read/write performance as the system can access the data from more than one place. This level of RAID does not provide any redundancy.

RAID Level 1

                Disk mirroring writes exact copies of data to more than one disk. Each disk or partition of a disk will contain the exact same data. If one hard disk fails, the data still exists on the other disk. This level of RAID also increases disk read performance as it can pull the data off of both disks.

RAID Level 2

                Uses Hamming error correction codes, is intended for use with drives which do not have built-in error detection. All SCSI drives support built-in error detection, so this level is of little use when using SCSI drives. It is seldom used at all today since ECC is embedded in almost all modern disk drives.

RAID Level 3

                Stripes data at a byte level across several drives, with parity stored on one drive. It is otherwise similar to level 4. It can be used in data intensive or single-user environments which access long sequential records to speed up data transfer. However, RAID-3 does not allow multiple I/O operations to be overlapped and requires synchronized-spindle drives in order to avoid performance degradation with short records.

RAID Level 4

                Disk Striping in which the parity information is written to 1 drive at a block level. The parity information allows recovery from the failure of any single drive. The performance of a level 4 array is very good for reads(the same as level 0). Writes require that parity data be updated each time. The process offers no advantages over RAID-5 and does not support multiple simultaneous write operations.

RAID Level 5

                Very similar to RAID level 4, however, parity information is written to each of the disks in the array. If one of the disks fails, the data can be reconstructed by installing a working hard disk. The parity information is used to reconstruct the data that was lost.

 For more in depth information on RAID, read

Terms and Concepts of Hardware and Software RAID - PART 1

Hard Drive Installation:

 The following procedure outlines the physical installation of a typical hard drive. Disconnect the power to the computer

Configure the appropriate master/slave settings or SCSI ID for the drive

Insert the drive into an available drive bay. If the drive is too small for the bay, you will need a mounting kit

Screw in the 4 screws - 2 on each side of the bay

If the drive is an IDE disk, connect the IDE cable to the drive. There should be a stripe along 1 edge of the cable. This stripe denotes pin 1. Pin 1 on the drive is usually closest to the power connector on the drive, however, you should consult the manufacturers documentation. Then connect the signal cable to the motherboard ID1 or ID2 interface making sure to note the pin 1 orientation there as well. If the drive is a SCSI drive, a SCSI cable would be connected from the drive to a SCSI controller card.

Connect one of the power supply's power connectors to the drive

In the old days, we had to launch CMOS and enter the CHS information for the drive, however, we no longer do that anymore because of a process called Autodetection. CMOS can still be used to configure the boot order and check for incorrectly jumpered drives.

 Due to the magnetic nature of hard disks, they should remain clear of magnetic fields.

 Once the drive has been installed it must be configured for use. In the old days of Windows 9x, we would use the DOS utility FDISK to create and format a partition to install Windows on. Newer operating systesm such as Windows 2000, 2003, XP, and Linux no longer rely on this step. These newer operating systems allow you to configure your partitions and formatting during the setup process after you run the bootable installation CD. There are also plenty of 3rd party tools such as Partition Magic that are popular for configuring disks to support multibooting among other things. Some additional disk configuration can be done after installation using a tool called Disk Management (Windows 2000, 2003, XP).

 So the first thing we need to do is determine how we wish to partition our drive. In the old days, we had one type of disk formatting scheme called basic disks. Windows 2000, 2003, and XP Professional have added a new type called dynamic disks which is proprietary to Microsoft.

 Basic Disk Partitioning:

 The number of partitions you can create on a basic disk depends on the disk's partition style. On master boot record (MBR) disks, you can create up to four primary partitions, or you can create up to three primary partitions and one extended partition. Within the extended partition, you can create an unlimited number of logical drives. A primary partition of a basic disk is a portion of the physical disk that functions as though it were a physically separate disk. On most Intel based systems this partition is the one that is marked as active which allows the computer to start up. You can create up to four primary partitions (sometimes called volumes) on a single disk or three primary partitions and an extended partition with multiple logical drives.

 Extended partitions allow you to create more than four individual volumes on a basic disk. Unlike primary partitions, you do not format an extended partition with a file system and then assign a drive letter to it. Instead, you create one or more logical drives within the extended partition. It's the logical drive of the extended partition that you format and assign a drive letter to. You can create an unlimited number of logical drives per disk.

 If you are installing Linux, you will notice that it supports an addition partition type called Swap. The swap partition is used as virtual memory like Windows' page file.

 Dynamic Disk Partitioning:

                The Windows installation disk only allows you to configure basic disks. If you want to convert your basic disks to dynamic, you can do so by using the Disk Management snap-in or the DiskPart command line utility. When you convert a basic disk to dynamic, all existing basic volumes become dynamic volumes.

                Dynamic disks provide features that basic disks do not, such as the ability to create volumes that span multiple disks (spanned and striped volumes), and the ability to create fault-tolerant volumes (mirrored and RAID-5 volumes). There are five types of dynamic volumes: simple (most common), spanned, striped, disk mirroring (RAID-1) and striping with parity (RAID-5). Mirrored and RAID-5 volumes are fault tolerant and are available only on computers running the Windows 2000 and 2003 Server family of operating systems.

 Once the drive has been partitioned, it must then be formatted which is the last step before operating system installation. Windows has supported a few different file systems over the years as follows:

FAT - The file system during the early years of DOS.

FAT 16 - Available during the later years of DOS and Windows 95.

FAT 32 - Became available after the release of Windows 95 OSR2 and was the format of choice for Windows 98/ME. FAT 32 is still supported in current Windows operating systems, but rarely used.

NTFS - NTFS was released with the first version of Windows NT and is now the format of choice for Windows 2000, 2003, XP, and the new Vista. NTFS offers major improvements over its predecessors offering redundancy, compression, security, encryption, cluster sizing, and disk quotas.

 As was mentioned before, the partitions and formatting of modern operating systems are configured during the installation from the bootable installation disk.

Further Reference:

Attended Installation of Windows XP Professional

Storage Tutorials

SCSI:

                SCSI stands for Small Computer Systems Interface and is a less commonly used, but faster alternative to IDE. Another advantage of SCSI is that only the controller uses an IRQ while the devices attached to it do not. SCSI devices are most commonly found in servers and high-end workstations.

 SCSI devices, such as hard drives and CD-ROM drives, plug into a SCSI controller internally or externally, and multiple devices can be configured in a chain. Internal devices connect using a 68-pin ribbon cable that is similar to that used for IDE devices. It is very important that you get the pin orientation correct when installing a SCSI drive. Failure to do so can destroy the SCSI device and/or the SCSI controller card. External devices connect to the SCSI controller on the back of the PC. To learn more about the various cable and connector types, read SCSI Connector Types.

 In order for the SCSI bus to work correctly, the last device on any SCSI chain must be terminated. Some SCSI devices are self-terminating, while others can be terminated using jumpers or a resistor that plugs into the end of the cable or device.

 Each device on a SCSI chain must receive its own SCSI ID including the controller. This ID can be set on SCSI devices using either jumpers, dip switches or dials. You will need to consult with the manufacturer of your device to figure out the correct method for setting the ID. New SCSI standards support up to 16 devices. The controller is usually preset to receive ID 7. A bootable hard drive would usually be set to ID 0 since it is the lowest on the list and the first to be accessed.

 SCSI controllers come with their own BIOS that offer configuration settings.

 Over the years, there have been a number of SCSI standards and increasing speed. The table below shows the details of the various SCSI standards:

Additional Reading

SCSI Tutorials

Floppy Drives:

                Floppy drives are also a form of magnetic storage that function similarly to hard drives. There is a spring loaded metal cover that is moved aside during operation that exposes a mylar disk that is coated with a ferro-magnetic substance. The drive's read/write heads access the disk as it turns on a spindle. Older PCs used 5.25 inch disks and drives that were able to hold 1.2mb of data. Modern 3.5 drives can hold 1.44mb of data. Given the popularity of newer storage types such as CDROM, ZIP disks and removable hard drives, it is not likely that further advancements to floppy technology will be made. In fact, many new computers are being built without them and it is probable that they will soon fade into oblivion.

 The following procedure outlines the installation of a floppy drive. Disconnect the power to the computer

Insert the drive into an available floppy drive bay Screw in the 2 screws

Plug the floppy cable into the drive and into the main board FD1 interface while noting the pin 1 orientation. The floppy drive will not work if the FDD cable is plugged in backwards. Note the twist in the cable. Connecting the floppy to the last connector on the cable will make the drive an "A Drive" while plugging it in to the connector toward the middle of the cable will make it a "Drive B"

Connect one of the power supply's power connectors to the drive

                If you are having problems reading a floppy disk, it is best to first check the disk. If it still will not read, you should try other disks to see if they work. Floppy disks do not last forever and can go bad just sitting around for long periods of time. If no disks will work in the drive, then you should check the cabling and make sure that everything is connected properly. Next, try a different floppy drive. They are very inexpensive and it might be worth installing a new one, or taking one from another computer for testing purposes. If the new drive does not work, then the most likely suspect is your FDD controller. If this is the case, you can purchase an external USB floppy drive, or buy an internal FDD controller card and install it in an available PCI slot.

CD-ROM Drives

 In addition to being able to play CD-audio disks, a CD-ROM drive can read data disks, and those with the CD-R or CD-RW designation can also record on CD media (more on this below). Here is how a CD-ROM works. A beam is emitted by the laser and directed onto a single track on the disc by a prism/beamsplitter. As the disc rotates, the beam encounters a series of pits and landings that determine whether the beam is reflected back into the detector(from a landing) or scattered(from a pit). Light from the laser beam must penetrate a thin protective layer of plastic on the disc before striking the reflective coating that contains the pits and landings. As the disc rotates, light reflected from landings on the disk strikes the photo sensor producing a series of electrical pulses that are coordinated with a timing circuit to generate a stream of 1s and 0s that produce the binary code of information on the disc. The average storage capacity for a CD-ROM is 680mb of data. CD-ROM speeds are listed as AxBxCx (i.e. 24x8x32x) where A is the write speed, B is the rewrite speed, and C is the read speed.

                Most current CD-ROM drives have the capability to record data. There are 2 main types of CD recorders.CD-R (Recordable) - Uses a chemical layer with a thin metal layer(silver alloy or gold). “Burning” removes reflective parts to simulate pits and lands and represent 1s and 0s. CD-R media comes in 74 minute 650MB capacity and 80 minute 700MB capacity versions.

CD-RW (ReWritable) - CD-RW media can be rewritten multiple times whereas CD-R can only be burned once. CD-RW uses phase-change material that crystallizes to write, and rewrite CDs through a heating and cooling process. You can only record on CD-RW media if the CD-ROM drive supports it.

 A common application for CD-ROM drives is burn MP3 files onto a CD. Let's say that you want to make a music mix from a bunch of CDs that you have purchased. First, you would need to rip the songs from CDA format to MP3 (some burning software includes this capability). After this is complete, you can burn your ripped MP3s onto a CD and play them in any CD player that supports the MP3 format.

 To burn a CD you will use software such as Roxio's Direct CD or Nero. Burning software will give you the choice of creating a audio CD which will play in your stereo, or a data CD which can only be read by CD-ROM drives.

 The following procedure outlines the installation of a CDROM drive. Disconnect the power to the computer

Configure the appropriate master/slave settings or SCSI ID for the drive

Insert the drive into an available drive bay

Screw in the 4 screws - 2 on each side of the bay

If the drive is an IDE, connect the IDE cable to the drive. There should be a stripe along 1 edge of the cable. This stripe denotes pin 1. Pin 1 on the drive is usually closest to the power connector on the drive, however, you should consult the manufacturers documentation. Then connect the signal cable to the motherboard ID1 or ID2 interface making sure to note the pin 1 orientation there as well. If the drive is a SCSI drive, a SCSI cable would be connected from the drive to a SCSI controller card.

Connect one of the power supply's power connectors to the drive.

Further Reference:

CD-ROM Tutorials

DVD Drives

                DVDs have nearly replaced VHS players in a relatively short amount of time. The reason for this is their incredible capacity for storing data and improved picture quality. Another major advantage is that DVD players became available for computers which did not happen with the VHS (can you imagine?). DVDs come in single-sided and dual-sided formats and can store 2 hours of video per side using the MPEG-2 compression standard. Because DVDs are compressed, they need to be decoded as they play. On a computer this can be done with the use of software or a hardware decoder. Hardware decoders use less CPU time.

 DVD-ROM drives are the most common type of DVD drives sold for computers. DVD-ROM discs can hold up to 16 GB of data, however, there are 2 newer technologies that are fighting for supremacy - HD DVD and Blu-ray. HD DVD was developed by Microsoft and offers media that can store 30GB of data. Blu-ray was developed by Sony and can hold 50GB of data. There won't likely be anything on the A+ exams about these 2 technologies, but it is probably good to know they exist.

 Just like CD-ROM players, DVD-ROM drives offer recordable versions. DVD-R and DVD+R can be recorded on once only. DVD-RW, DVD+RW and DVD-RAM are rewriteable. DVD drives can play CD-ROMs and all DVD writable drives can burn CDs as well. DVD players connect to the PC in the same way that CD-ROM drives do using either an ATAPI or SCSI interface.

 One of the biggest problems with DVD-ROM technology is compatibility because of all of the different media types. A while back, if your friend gave you a burned DVD-RW, you wouldn't be able to edit it with your DVD+RW drive. In fact, you might not even be able to PLAY it on your drive. This has been addressed to some degree with the release of DVD±RW combo drives which can record on just about anything. The next problem is finding out if the DVD you burned will play on the DVD player in your home entertainment system and you will have to check the specs on yours to see what formats it supports.

 Another problem with DVD media that can cause headaches is the fact that some media, particularly the cheap stuff, just doesn't work well (or at all) in certain drives. If you find media that works, it is best to stick with it. If you are having problems, make sure you have media that your DVD-ROM drive supports and try a higher quality to see if that helps.

 When working with CD-ROM and DVD-ROM burners, one of the most common problems is buffer underruns. Burners come with buffer RAM onboard that temporarily stores the data coming from the source. There are many causes for buffer underrun errors, but following are the most common things that will fix this. Make sure that your burner has a large enough buffer.

Make sure that you close as many applications and processes on your computer before burning. Also make sure that screen savers, anti-virus software, etc. do not start running while you are burning.

Try burning at a slower speed. Make sure that your media is not scratched or dirty.

Tape Drives:

                Tape drives appear to be fading away so you might not see anything related to this section on the exam. With advances in digital and optical storage technologies as well as advancements in Windows' backup capabilities (e.g. back up to network storage), this technology is becoming obselete.

                Tape drives are another form of magnetic storage media that functions similarly to the other types. The tape is belt driven and read/write heads magnetize portions of the tape as it passes by them. Tape drives are typically used for backing up and storing data. Because they are comparatively slow, they are used to store data that does not need to be accessed very often. Older versions of tape drives were quarter-inch cartridges(QIC) that were approximately 6" x 4" in size. Improvements in encoding enabled advancements in the amount of data that could be stored on these tapes.

 The newest advancements in tape technology (which aren't very recent) have brought about Digital Audio Tape(DAT) and Digital Linear Tape(DLT). DAT tapes work in a similar fashion as a VCR tape and can store much larger amounts of data than the QIC formats. There are several different DAT standards as follows:

 Tape Drives are typically connected to Parallel or SCSI ports.

Flash Drives and Flash Cards

Also known as thumb drives, USB flash drives offer advantages over other portable storage devices and are partially responsible for the disappearance of floppy and ZIP disk technologies. They are more compact, generally faster, hold more data, and are more reliable due to both their lack of moving parts (solid state), and their more durable design. These types of drives use the USB mass storage standard, and therefore, can be used with Linux, Mac OS X, Unix, and Windows. The drive is simply plugged into the computer's USB port and it registers as removable storage in My Computer (Windows). Newer computer systems will also allow these drives to be selected as the boot device which can be useful for storing certain utilities and troubleshooting tools. In Windows Vista, the ReadyBoost feature allows use of a flash drive to supplement system memory. At the time of this writing there are flash drives with a storage capacity of up to 64 gigabytes.

                Another type of removable storage is flash cards which come in several different varieties and are used with portable devices such as digital cameras, cell phones, and PDAs.

CompactFlash is the oldest and largest of the flash card types and is based on a simplified PCMCIA bus. CF cards come in CF I and CF II sizes, the latter being thicker. Like all other flash cards, the CompactFlash cards are solid state, although some manufacturers have turned this form factor into microdrives which are minature hard drives. These drives have platters and heads just like a regular hard drive. The two types look identical, however, microdrives can use too much power for some devices, but are less expensive.

Secure Digital (SD) cards are the most commonly used format today after displacing a similar type by SmartMedia. SD cards come in 2 types: SD and SDIO. Both are identical looking so you need to check with the manual or manufacturer of your device to find which to use. SD cards are smaller than CompactFlash, but come in 2 even smaller sizes: MiniSD and MicroSD are smaller versions that are commonly used in cell phones.

                There are other types of flash media such as memory sticks which are a proprietary flash card used by Sony and xD picture cards which was developed by Olympus and is used in digital cameras.

 For popular formats such as SD cards and CompactFlash, there are USB cardreaders available that can be attached a computer. Some printers, home entertainment systems, and computers come with card readers built in.

Thank you

1.7 Multimedia

Contents:

§  Video Displays

§  Video Adapters

§  Troubleshooting Video

§  Sound

Video Displays

Introduction:

                Video displays, also known as monitors, are responsible for displaying the picture that is output by the PC. There are 3 basic types of displays: CRT, LCD, and projection which are discussed in more detail below.

CRT:

CRT displays were the most common type and were basically just like a traditional television set. They are on their way to obscurity and are being replaced by the newer LCD type of display. CRTs are based on the use of an electronic screen called a cathode ray tube (CRT). The CRT is lined with a phosphorous material that glows when it is struck by a stream of electrons. This material is arranged into an array of millions of tiny cells, usually called dots. At the back of the monitor is a set of electron guns, which produce a controlled stream of electrons. These guns start at the top of the screen and scan very rapidly from left to right. Then, they return to the left-most position one line down and scan again, and repeat this to cover the entire screen. The electron guns are controlled by the video data stream coming into the monitor from the video card which varies the intensity of the electron beam at each position on the screen. This control of the intensity of the electron beam at each dot is what controls the color and brightness of each pixel on the screen. The entire screen is drawn in a fraction of a second.

 Color monitors have 3 electron guns that control the display of red, green and blue light. The surface of the CRT is arranged to have these dots placed adjacently in a specific pattern. There are separate video streams for each color coming from the video card, which allows the different colors to have different intensities at each point on the screen. By varying the intensity of the red, green and blue streams, the full gamut of colors is achieved.

 The surface of the CRT only glows for a small fraction of a second before beginning to fade. This means that the monitor must redraw the picture many times per second to avoid having the screen flicker as it begins to fade and then is renewed. The speed of this redrawing process is called the "refresh rate".

 Display quality depends on the resolution, which is measured as the number of horizontal times the number of vertical pixels. Common resolutions today are 1024x 768, 1280 x 960, 1280 x 1024, and 1600 x 1200. Notice that each of these uses a 4:3 ratio which is known as the aspect ratio. The aspect ratio is different for widescreen and other formats.

 Another factor affecting quality is Dot Pitch. Dot Pitch is a measurement of the distance between dots of the same color on the screen. The closer together they are, the smaller the dot pitch and the better the picture. Dot Pitch is measured in millimeters.

Most CRT displays connect to the video adapter via a DB-15 connector on the board. Older video standards utilized a 9 pin connection. Some high performance monitors are connected via a BNC connection.

LCD:

Liquid Crystal Display (LCD) panels were previously only available for laptops, however, they are now the most common type for PCs as well. Why LCD? They are lighter, thinner, have a better picture, use less than half the power, and do not flicker like their CRT counterparts. As the name would imply, this technology uses a liquid with crystals in it. LCDs have resolution, refresh rates, and the other discussed terms in common with CRTs. Below are a few terms that are specific to LCDs.

Response Rate - This refers to the amount of time it takes for all of the pixels on the screen to go from black to white and back to black.

Contrast Ratio - This is the difference between the lightest and darkest spots that the LCD can display.

Backlighting - LCD monitors are backlit for brightness. The strength of this backlighting affects the overall picture quality.

Unlike analog CRTs, LCDs use a digital signal. The output from a video card is initially digital, but they use a chip called RAMDAC which converts the digital output to analog for use with CRT monitors. Well, what if you are using a LCD monitor? Fortunately, most LCDs are able to convert the analog stream back into digital. In fact, many LCDs offer a DB-15 connector just like their CRT predecessors. With the newer standards found on many video cards and all LCDs, no conversion is necessary. This is thanks to DVI and HDMI (the current standard) connections.

DVI (Digital Visual Interface):

 DVI is a video interface standard designed to provide very high visual quality on digital display devices such as flat panel LCD computer displays and digital projectors. DVI can support the current video standard 1080p.

 There are 3 types of DVI interfaces as follows:

DVI-D - True Digital Video DVI-D format is used for direct digital connections between source video (namely, video cards) and digital LCD (or rare CRT) monitors. This provides a faster, higher-quality image than with analog, due to the nature of the digital format. All video cards initially produce a digital video signal, which is converted into analog at the VGA output. The analog signal travels to the monitor and is re-converted back into a digital signal. DVI-D eliminates the analog conversion process and improves the connection between source and display.

DVI-A - High-Res Analog DVI-A format is used to carry a DVI signal to an analog display, such as a CRT monitor or an HDTV. Although some signal quality is lost from the digital to analog conversion, it still transmits a higher quality picture than standard VGA.

DVI-I - The Best of Both Worlds DVI-I format is an integrated cable which is capable of transmitting either a digital-to-digital signal or an analog-to-analog signal, but it will not work transmitting a digital-to-analog or analog-to-digital signal.

 In addition to the above formats, the DVI interface has 2 additional types: single link and dual link. Dual link has a lot more pins so it offers higher throughput, hence, better resolutions can be supported. Below is a chart of the various DVI types available:

HDMI (High-Definition Multimedia Interface):

HDMI is an audio/video interface for transmitting uncompressed digital data. It is a digital alternative to previous analog standards, such as coaxial cable (RF), composite video, S-Video, component video, VGA, and others. HDMI connects devices such as Blu-ray players, AVCHD camcorders, computers, video game consoles, stereo receivers, computer monitors, digital TVs, and others. HDMI supports 1080p video, 3D video, and 8 channels of 24-bit 192kHz audio. The big advantage of HDMI is that it supports video and sound with one cable and connector unlike DVI which just supports video. The connector is much smaller than DVI's as well. HDMI offers a feature called DDC which is similar to the plug-and-play feature in Windows. Devices can be automatically configured to work with each other without manual configuration. HDMI also supports High-Bandwidth Digital Content Protection (HDCP) which prevents copyright infringing media from playing at full resolution. HDMI is backward compatible with DVI via the use of an adapter.

Projection:

 Projectors, like the ones often used in board rooms and class rooms, project what is showing on the computer screen onto a wall or screen. Just like monitors, there are CRT and LCD projectors. Strangely enough, CRT projectors are typically have a higher quality picture, but they are much larger, heavier, and more expensive. LCD projectors, while lacking high end picture quality are usually portable.

 Below are a few terms you might want to know regarding projection displays:Lumens - This refers to the brighteness of the projector. The number of lumens that is appropriate depends on the size and brightness of the room it will be used in.

Lamps - The lamp is essentially a heavy duty light bulb that produces the light needed by the projector. They do fail and are fairly expensive to replace. The also generate a lot of heat, but the projector will have a fan to cool it.

Throw - This is the size of the image on the wall or screen given a certain distance from it. Projectors have a minimum and maximum throw distance that varies depending on the lens it has.

Further Reference:

http://www.pcguide.com/ref/crt/index.htm

http://www.pctechguide.com/42CRTMonitors.htm

Video Adapters

Introduction:

                The video card, also known as the display adapter, is the component that provides communications between the the system board and the display. Video cards are typically an expansion card that is inserted into the motherboard, however, many systems come with onboard video. Typically, onboard video isn't near the quality of a high-end video card so many gamers, graphics professionals, and others choose to add a video card instead.

Standards:

                As with everything else, there have been several different standards over the years with many of them coming in the last couple of years. The table below has more information:

                Video cards contain their own RAM (VRAM) that allows them to support higher levels of color depth, resolution and performance. Unfortunately, the PCI bus which offers a throughput of 132 MBps, was unable to keep up with the increasing demands of newer technologies. The Advanced Graphic Port (AGP) was developed to attain even higher performance levels including 3-D graphics texturing. This was achieved by creating a direct connection to the northbridge on its own bus. AGP is derived from the PCI specification and is only used for video adapters. There are several AGP levels that are listed in the table below:

 The multipliers 1x, 2x, 4x and 8x refer to the number of times the signal is increased per clock cycle.

 Like AGP, the PCIe interface is also based on the PCI standard, but has speeds much faster than AGP or PCI. In fact, with its theoretical throughput of 16 GBps, it is sure to replace AGP for graphics cards and is already being used for that purpose.

Installation:

                Where you will install a video card depends a lot on what type of video card you have and which slots are available. If the card is AGP, there is only one choice as motherboards only have 1 AGP slot. If installing a PCI or PCIe card, it is good idea to leave the slot on the fan side of the video card blank for ventilation as modern video cards can get pretty hot. Once you have identified the correct slot, simply insert the edge with the metal contacts into the slot making sure not to touch the contacts. Once inserted, screw the card into the case to lock it in and connect the monitor cable to the back of the card. The final step is to install the driver for the video card. This will usually be located on an accompanying disk, however, it is usually better to go download an updated driver from the manufacturer's website which may contain bug fixes and enhancements.

Troubleshooting Video :

                The most common video problem is incorrect settings in the video card properties. When viewing these properties, Windows will often allow you to set the resolution and/or color depth to a level that your monitor can't support (but your video card can). For example, if your monitor only supports a maximum resolution of 1024x768, but you change the properties in Windows to 1280x1024, the screen is most likely going to get garbled, or more likely go blank with static lines. Fortunately, most video cards require a confirmation after the change is made and if it is not confirmed, it will revert to the previous resolution after a short waiting period. If for some reason incorrect settings are made, you can boot into safe mode (more about this in the operating systems section) which uses a VGA display mode (640x480) and you can change the settings back manually.

 Another common problem is the installation of an incorrect driver. If you are having video problems, make sure you have the correct and updated driver from the manufacturer. Again, you can use safe mode to uninstall the current driver and install the correct one.

                Video cards don't have too many hardware failures. If the card has a fan, it can fail and cause the card to overheat. You can always open the case to make sure the fan is still running. This and other hardware failures will typically result in a garbled screen and possibly lock up the computer. One way to confirm a hardware failure is to use our trusty friend safe mode. If the problem doesn't show up there, it probably isn't a hardware problem and is more likely one of the above.

 If you suspect that an onboard video adapter has gone bad, you can insert a video adapter and see if that works. If so, you can replace the motherboard, or just continue running the video off the video card.

 You should never attempt to repair a CRT monitor as they can contain electrical charges as high as 30,000 volts - a potentially lethal amount. Most display repairs should be referred to a professional and are not typically part of a hardware technician's job due to the complexity and danger involved. Keep in mind that a large number of repair jobs will cost as much or more than the monitor itself. Typically, when a monitor goes bad, it is replaced.

Sound :

Sound Cards

                Your computer's sound card is responsible for taking sound data from a disk (like an MP3 file) and converting it so your computer's speakers can play it. Usually, this tweaking consists of changing digital ones and zeros into analog waveforms your ears can recognize. This process is referred to as sound output.

 The sound card is also responsible for doing it the other way around. It takes external sounds such as your voice as you talk into a microphone and converts those waveforms into ones and zeros so that they can be stored on a disk. This process is referred to as sound capture.

 Sound cards are internal cards that are either built into the motherboard or are installed in an expansion slot - usually PCI. The back of the sound card contains RCA jacks for connecting speakers and microphones.

 When choosing a sound card, you will need to take into account a variety of considerations since not all sound cards are created equal. For example, many sound cards support surround sound and have inputs for multiple speakers. Others provide sub-woofer support, a joystick jack, and possibly other features.

 Installation of a sound card is basically the same procedure as described above for a video card. Once the card is installed, you will need to connect an MPC2 cable from the sound card to each of your optical drives (or they won't play sound). In the back of the sound card, plug in your speakers, microphone and any other devices. Install the latest driver from the manufacturer.

Formats:

 Sound on your PC can be in a wide variety of formats, many of them proprietary. The most common are WAV, MP3, and WMA. Let's take a look at a few common formats a little more in depth.

WAV - Once the most common format. WAV files can be very high-quality, but suffer from large file sizes.

MP3 - The MP3 format was developed to remove some of the unnecessary sound data thus creating smaller sized files. This compression has allowed MP3 to become the most common format used today.

MIDI - The Musical Instrument Digital Interface format uses text files that provide a series of instructions to a sound card as to which notes to play on which instruments. The sound when played depends on the capabilities of the sound card. Since this format uses synthesis, it is rarely used for listening to music. In fact, MIDI is not used much anymore except occasionally in games. MIDI files are extremely small.

WMA - Windows Media Audio is a fairly popular format. It is proprietary to Microsoft and plays on the Windows Media Player.

AIFF - The Audio Interchange File Format is common on Macintosh computers and play in QuickTime player.

 There are a number of video formats that contain sound and you have to make sure that you have the proper codec installed to support the video and sound. Common formats for video with sound are: AVI, MPEG, MOV, WMV, and DIVX.

Troubleshooting Sound:

                Most problems with sound are pretty easy to figure out. If you are having a problem getting sound, check the following items: Make sure that the speakers are on and the volume is turned up high enough on the speakers. On the computer, make sure that volume in Windows is turned up and not muted. Make sure that your speakers are plugged into the correct RCA jack on the sound card. Make sure that you have the correct driver installed. If you aren't getting sound from an optical drive such as a DVD-ROM player, make sure you have the MPC2 cable connected correctly. If particular file formats aren't playing, make sure you have the correct codec's installed and are using a media player that supports the format you are trying to play.

Thank You

1.8 Input Devices

Contents:

§  Introduction

§  Serial

§  Parallel

§  USB

§  Fire wire

§  Keyboards

§  Mice

§  Digital Cameras

§  Web Cameras

§  Specialty Devices

Introduction:

                A PC requires a variety of external devices in order to function - some of these are input devices and some are output devices. As the names imply, an input device provides information TO the PC while an output device provides you with data FROM the PC. Common input devices include mice, keyboards, webcams, digital cameras, and scanners (scanners are discussed in Domain 4.0). There are also specialty input devices such as bar code scanners, fingerprint scanners, touch screens, and others. Common output devices are monitors and printers, both of which are discussed in other sections of this guide. In this section, we are going to discuss the various common and specialty input devices and the ports and connectors that they use.

Serial:

                Before we begin looking at devices, we need to discuss the ports that are available for connecting these devices. Serial ports are nearly extinct and have been largely replaced by USB and Firewire, but they do still exist. The most common places they are still seen today are the built-in modems on laptops and the communications port on many routers. Their other main function was for mouse connections.

Serial devices used a DB-9 connector (see left image) that plugged into a DB-9 port on the computer. Because the expansion bus uses parallel communications, the serial port on the computer has a chip called Universal Asynchronous Receiver/Transmitter (UART) that is responsible for converting between the parallel and serial data streams. RS-232 is the standard that defines all of the specifications of serial communications.

 Nearly every device we work with in modern PCs is plug-and-play so we don't spend much time manually configuring ports anymore. The serial port is the exception, and in most cases, must be configured in the Device Manager. The exception to this rule are modems which have their own built in serial ports. They still use a COM port like other serial devices, but their settings are pre-configured internally. The other major problem with the serial port was its lack of speed which maxxed out at 115 Kbps.

Parallel Port:

                Most PCs still have a parallel port, although it is being used less and less. The main function of the parallel port was for connecting printers and scanners. Both of these devices are largely connected via USB (some printers are now networked). The maximum speed of a standard parallel port was 115 Kbps, although the later EPP/ECP varieties increased this speed to 3 MBps.

 Parallel connectors are DB-25 and use a male to connect to the PC and a female to connect to the device. These connectors are shown below.

USB:

                Serial and parallel ports are very slow by modern standards and suffer from a host of other problems. This led to the development of the Universal Serial Bus (USB) which has become the standard for connecting peripherals (input/output devices). USB has the advantages of being much faster, it is plug-and-play compliant, the bus is expandable via the use of USB hubs, and devices are hot-swappable. USB comes in 3 basic speeds as follows:

Low Speed - Has a rate of 1.5 Mbps that is mostly used for Human Interface Devices (HID) such as keyboards, mice, and joysticks.

Full Speed - Has a rate of 12 Mbps. Full Speed was the fastest rate before the USB 2.0 specification and many devices fall back to Full Speed. All USB Hubs support Full Speed.

Hi-Speed - Has a rate of 480 Mbps and is known as USB 2.0. Though Hi-Speed devices are advertised as "up to 60 MB/s", not all USB 2.0 devices are Hi-Speed. Most hi-speed USB devices typically operate at much slower speeds. USB 2.0 devices will work on USB 1.x hubs, but will run at the lower speed.

 USB utilizes 4 different connection types as follows:

USB A - The USB A connector is side of the cable that plugs into your PC's USB ports. Most input devices do not use this type of connector on their end - they use one of the 2 types below.

USB B - This connector is easy to spot because it is square. It is plugged into a variety of peripherals, but you'll never see this port on your PC.

USB Mini-A - This is the newest standard used for connecting smaller devices for USB On The Go (OTG). USB OTG allows consumers to connect mobile devices without a PC. For example, USB OTG lets consumers plug their digital camera directly into a compliant printer and print directly from the camera, removing the need to go through the computer. Similarly, a PDA keyboard with a USB OTG interface can communicatea with any brand PDA that has a USB OTG interface.

USB Mini-B - This small connector is common for connecting smaller devices such as digital cameras and phones. Again, you will never see this port on your PC.

 USB runs off of a host controller that is usually an integrated circuit that is part of the motherboard chipset. The host controller can support up to 127 devices. Most PCs only have a few USB ports, so the other options are to install an expansion card with more USB ports, or use a USB hub (much more common option). Although there are probably very few instances where 127 would be used, there are a couple of important things to note about connecting too many devices. USB devices divide the USB bandwidth between them in a first-come first-served basis and it is not uncommon to run out of bandwidth if too many devices are using. Along the same lines, many USB devices are bus-powered which means that they get their power or battery charging from the USB connection. Too many of these can cause a power drain on the system and cause the devices to not work correctly. Another thing to watch out for with USB is to note that the cable must be less than 5 meters long.

 When installing a USB device, it is important to remember to install the driver before connecting the device. The reason for this is that Microsoft operating systems come with generic built-in drivers and when you plug in a USB device, Windows will typically install one of these if it can't find the official driver. The Microsoft drivers may or may not work, but more importantly, they may be missing features that your product supports. That is why it is always a good idea to install the driver that came with the product, or download and updated one from the manufacturer's web site.

Firewire:

 Firewire was developed by Apple and is also known as IEEE 1394. Firewire is another high speed connection type for input/output devices that has most of the same features as USB. In fact, Firewire came out before USB and was much faster. Firewire did not become the standard that many thought it would be due to licensing fees implemented by Apple. Firewire is still around, but is not nearly as common as USB despite the fact that theoretically and practically, it is much faster.

 Firewire has 2 speeds: 1394a which runs at 400 Mbps and 1394b which runs at 800 Mbps. It can support 63 devices which can use a hub, or be daisy chained (like SCSI devices). The maximum cable length between 2 devices is 4.5 meters.

Firewire has 2 different connector types, both of which can be found on a PC. One is a 6-pin connector that provides power to input devices and the other is a 4-pin connector that does not. Like USB devices, it is generally a good practice to install the driver before connecting the device.

Keyboards:

Keyboards are one of the oldest and most common input devices. They connect to the motherboard at the back of the PC (USB keyboards can connect in front if there front-side USB ports). Older keyboards used a 6-pin mini DIN connector knows as PS/2, however, newer keyboards are typically USB or wireless. Most keyboards are of the 101/102 key variety.

 Most keyboards simply plug in and work. Some advanced keyboards may need to have a driver installed for advanced features. Keyboard features can be configured in the keyboard control panel applet.

 A PS/2 keyboard should never be attached or unplugged while the computer is on as they are not hot-swappable like USB keyboards. If a wireless keyboard start behaving erratically, it most likely needs new batteries.

Mice:

                The other most common input device is the mouse which has evolved significantly over the last several years. Older mice also used a PS/2 connection as described above. The mice and keyboards were color coded to help prevent them from being plugged into the wrong port. If you plugged the mouse into the keyboard port and the keyboard into the mouse port, neither would work. Normally, you would get a 302 keyboard error during the boot process. Like keyboards, PS/2 mice have all but been replaced by USB and wireless varieties.

 In addition to the connection type, the mouse itself has changed in recent years. Older mice used a ball and rollers which often got dirty and had to be regularly cleaned. Newer mice, called optical mice, use LEDs or lasers to track the movements of the mouse. Optical mice rarely require any maintenance or cleaning. In addition to this improvement, many mice now come with a scroll wheel between the 2 buttons that allows you to scroll pages on the screen up and down.

 A mouse can be configured in the Mouse control panel applet. This allows you to adjust such settings as double-click speed, acceleration, right-hand/left-hand orientation, and other settings.

Digital Cameras:

                Digital cameras have been slowly replacing film cameras for many applications as prices have come down over the years. They offer the advantage of being able to view a picture right after it is taken, massive storage, and of course, the ability to connect to a PC. Almost all digital cameras connect to PCs via a USB connection - typically USB mini-B. Once connected, pictures can be saved to the hard drive, emailed to people, and printed. Most cameras come with some sort of software for managing pictures. Windows XP offers a wizard that will help you download the pictures from your camera. Many cameras will also show up in My Computer and you can open the camera like you would your hard drive and browse the contents. Some computers and printers have card readers that you can insert the memory card directly in to.

 The quality of picture a digital camera can take is measured in megapixels - higher being better. It is important to note that the higher the quality, the bigger the file size and the less pictures you can fit on a memory card.

Web Cameras:

                Web cameras, or webcams, are mainly used for web conferencing (and porn, but that won't be on the exam) and typically connect via USB. Applications such as MSN Messenger and Skype allow you to video conference with another person with a webcam for free. Not all webcams are equal and vary widely on quality. Quality is basically determined by 2 things: resolution and frame rate. Like digital cameras, resolution is measured in megapixels. There are webcams with very high resolution, however, this creates large video sizes that are difficult to transmit over the internet. The frame rate is the number of "pictures" your camera takes per second. The higher the frame rate, the smoother the video will appear on the other end.

 Most webcams come with drivers that should be installed before connecting the camera. Once installed, you can usually access the camera's properties in the control panel where you can modify audio settings, video settings, and access special features such as facial recognition if offered.

Specialty Devices:

                There are many less common input devices, some proprietary or custom built, that can be connected to a PC. Below is a brief discussion of a few of them.

Biometrics are playing an increasing role in computer security and biometric devices are becoming more common on PCs. These devices provide access security by requiring verification of a person's identity. There are many different kinds including fingerprint scanners, retina scanners, and voice recognition software just to name a few. These devices can be built into the PC, keyboard, or other device, and they can also be external devices usually connected to a USB port. After installing such a device, you will likely need to do an initial scan of whatever biometric information the device measures so that it knows what to look for in the future.

Touch screens are computer monitors that are technically input and output devices. You input commands by touching the screen with your finger or a stylus. These are most commonly found in PDA format or in store/information kiosks. Touch screens allow one to get rid of the keyboard and mouse. In addition to the regular monitor connection, there will usually be a separate USB or PS/2 connection for the mouse portion of the monitor. This will typically require driver installation.

Bar code readers are used to read standardized Universal Product Code (UPC) bar codes that are commonly found on most products you will find in any major store. Bar codes readers can scan product information to the PC to update inventory databases. Modern readers use a USB, PS/2, or wireless connection and typically interface with specialized software.

Thank You

1.9 Maintenance

Contents:

§  Introduction

§  Outside of the Case

§  Inside of the Case

§  Drives

§  Input/Output Devices

Introduction:

 Regular cleaning of computers and their components can extend their lifespan, prevent accidents and injury, and save money. Computers and their components are delicate pieces of equipment, so proper and regularly scheduled care is very important. Below are cleaning tips for various items.

Outside of the Case:

                Cleaning of outer surfaces of a computer can be done with soap and water as long as the solution does not enter the internal parts of the computer. The solution should be applied with a lint-free cloth. The cleaning should be followed with an anti-static spray that can be made out of water and fabric softener.

 Computer equipment should not be placed in areas of extreme temperature or humidity. It should also not be located near any magnets such as those found in speakers.

Inside of the Case:

 Internal dust can be cleaned with canned air, a soft brush, or anti-static vacuum. Anti-static vacuums are specially grounded to prevent static discharge like regular vacuums. Dust can contribute to overheating problems. Making sure that all expansion slot covers are in place can reduce dust buildup. Missing covers can also disrupt the airflow design of the case and cause overheating problems. Additional fans can be added to help cut down on internal temperature problems. As mentioned in the CPU section, there are newer cooling options such as liquid cooling for CPUs.

                Oxidation corrosion can slow down or even prevent electricity from flowing through contact points. Oxidation buildup can be removed by rubbing with an emery board or eraser. It can also be cleaned with a special cleaning solution.

Drives:

 Floppy drives can be cleaned using a cleaning kit available at computer stores, or use a cotton swab with isopropyl/denatured alcohol to clean the inside of the drive.

 Other than keeping the dust off of them as described above, hard drives don't get physically cleaned. There are, however, 2 important maintenance tasks that are done through the operating system. Hard drives can have clusters go bad so it is important to check for these so that the operating system knows not to use them. In Windows, error checking can be done in the following manner:

Open My Computer→Right click on the drive to be checked and select "properties".

Click on the "Tools" tab.

Click on the "Check Now" button.

 Hard drives can become littered with unneeded files. To clean these up, follow the instructions above, but click on the "Disk Cleanup" button on the general tab instead.

 If a CD-ROM or DVD-ROM player is no longer reading discs, you might want to try a cleaning kit. If the problem only appears to be with one CD or DVD, it is either scratched or dirty. If dirty, use a CD cleaning fluid and anti-static cloth.

Input/Output Devices:

 Monitors should be cleaned with an anti-static wipe. Do not use household cleaning solutions as they can damage the screen. Some LCD screens have to be cleaned with a special solution. LCD monitors should not be located in overly cold or humid environments.

                Keyboards can tend to collect dust between the keys. They can be vacuumed with a small vacuum or the dust can be blown out with compressed air while holding it upside down. If you spill liquid inside a keyboard, it can often be repaired by taking it apart and cleaning the inside, however, most keyboards are so inexpensive that it usually isn't worth it.

 Ball mice need to occasionally have the X and Y rollers cleaned with a lint-free swab, while little maintenance is needed on optical mice. If an optical mouse starts behaving strangely and you know the batteries are good, try cleaning the optics with a damp cotton swab.

 Printer and Scanner care instructions are discussed separately in Chapter 4.0.

Thank You

2.1 Laptop Hardware

Contents:

§  Introduction

§  Power

§  Processors

§  Memory

§  Hard Drives

§  Modular Drives

§  Displays

§  Docking Stations and Port Replicators

§  PCMCIA

§  Express Card

§  Mini PCI

§  Laptop Control Devices

§  Function Keys

Introduction:

This is the first tutorial in our Laptop and Portable devices guide. There are many different terms used for these devices including portable computers, notebooks, and laptops. In this guide, we are going to call them laptops. This particular section of the guide will discuss laptop hardware and accessories.

Power:

                Laptops can run on AC power or on rechargeable batteries. There are 3 types of batteries that are used in laptops as follows:

Nickel-Cadmium (Ni-Cd) - This is an older technology that had a few problems. First, the batteries needed to be completely discharged before recharging or they wouldn't hold a very good charge. This was known as battery memory and resulted in comparatively short lifespans. They also had problems when overcharged. These batteries are extremely toxic and MUST be recyled.

Nickel-Metal Hydride (Ni-MH) - Still commonly used today, these do not have the charging problems that the Ni-Cd types did. They are much less toxic, but should still be recycled.

Lithium-Ion (Li-Ion) - These are the most commonly used batteries used today. They can hold a charge much longer than their predecessors, although cannot be recharged as many times. If a lithium-ion battery is overcharged, it can explode which is why devices that use these batteries have a built-in mechanism to prevent overcharging.

                Fuel cell batteries are being developed now, but this technology is still very new and probably won't be on the A+ exams.

 Although power management is used with desktops, it is of much greater concern with laptops. Today, we use specifications known as Advanced Power Management/Advanced Configuration and Power Interface or APM/ACPI to manage computer power. Devices that work with these specifications are known as Energy Star compliant which means that they use less power and allow APM/ACPI to shut them off when not being used. In addition to compatible devices, modern power management requires a compliant BIOS and operating system. All BIOSes offer APM/ACPI and newer Windows operating systems support APM/ACPI.

 APM/ACPI is either configured through the BIOS or the operating system, however, the settings in the OS will override the BIOS settings. To access the power management features in Windows, open the Power Options control panel applet. Note that some laptops come with their own proprietary power management applications that may look different and have different features than what you see below.

 This allows you to select from a variety of preconfigured power schemes (such as Portable/Laptop) or you can manually configure the settings for hard drives, monitors, etc. There are a couple of different power states that can configured in the Power Options control panel or they can be activated manually. These states are described below:

Stand by - Stand by, also sometimes called is a light sleep mode you can put your computer in. When you resume from Standby mode, you'll be exactly where you left off with all of your applications and documents still active on the screen. While in this mode, the hard drive usually stops running, the display turns off, and the fans might even turn off, but the computer still needs to be connected to a power source (battery or AC) or you will lose your work. On many laptops closing the lid or pressing the power button puts the laptop into standby mode. Another manual method is to click the Start Button and select Shut Down. After the Shut Down Windows screen appears, select Stand by (See image below).

Hibernate - Hibernation mode is the same as stand by, however, the hibernate mode allows you to turn off the computer completely and even unplug it from power. It takes longer to resume from a hibernated state. You can manually put your computer into hibernation mode by selecting Hibernate from the Shut Down Windows screen mentioned above.

Processors:

                Both Intel and AMD make processors for laptops. These special CPUs are smaller, use less heat, and less power. On some laptops, these processors are upgradable, however, there are a couple of things to beware of:

Heat - Laptops are sensitive to heat and difficult to cool. A perfect example of this is my Toshiba Satellite which runs too hot for the design. It has to have the back propped up on a book to get more airflow underneath or else it overheats and shuts off. If you replace your CPU with one that runs too hot for the design of your system, you will likely run into overheating problems.

Installation - Installation of a laptop CPU may basically require you to tear the entire thing apart and put it back together. This depends on the particular make and model, but you should check out the procedure before deciding to upgrade.

Memory:

 The majority of laptops have upgradeable RAM slots and most current laptops use 200-pin DDR/DDR2 SO-DIMMS, although some use 172-pin micro-DIMMS. Older laptops used 72 or 144-pin SDRAM SO-DIMMS. Some older laptops used proprietary RAM that had to be purchased at high prices from the laptop manufacturer.

 Some laptops use a system called Shared Memory whereby the manufacturer includes less RAM on the video card which in turn helps itself to the system memory. The reason for doing this is that it make the video component much less expensive, however, the obvious side-effect is that the system will often have less than its full amount of RAM available when the video is using it.

 Installing RAM on a laptop varies widely by manufacturer. The location of the RAM will vary widely, but in most cases there is a panel on the underside of the laptop that must be unscrewed.

 For obvious space saving reasons, laptop RAM isn't vertically oriented as in a desktop computer and lays down flat. To remove the RAM, there will be some sort of lever or other restraining mechanism. In the image below, this laptop has a metal restraining metal piece which the white arrows are pointing to.

 If we push these metal pieces outward, the RAM pops up at a 45 degree angle as shown below.

 At this point, you can simply pull the RAM out and insert a new one. After inserting the new one, press down lightly and the metal clamps should automatically lock in. Again, the locking mechanism can vary by manufacturer, but most are similar to this.

Hard Drives:

 There isn't too much to talk about regarding laptop hard drives. They are the same as desktop hard drives, only they are smaller and have smaller storage capacities for the most part. Desktop hard drives are 3.5 inch and laptop hard drives are 2.5 inch.

 To remove or install a hard drive, there is usually a panel on the underside of the computer just as there is for memory. Unscrew the panel and insert or remove the hard drive.

Modular Drives:

 One of the coolest features of laptops is the ability to configure drives the way you want. Most laptops have drive bays (also known as media bays or accessory bays) that can be ejected and replaced with a different component. For example, my laptop currently has the battery stored in the first drive bay and a CD/DVD-ROM drive in the other. Each of these drives has a lock and a release button on the bottom of the laptop. When unlocked and the button is pushed, the drive or battery can be pulled out and replaced with something else.

 This particular laptop doesn't have the most convenient method for swapping out drives - others have systems that don't require you to flip the computer upside-down.

 Let's say that I won't be needing my CD/DVD-ROM while I travel. I can replace it with a spare battery and get longer life between charges. Or let's say I worked for a company that still uses a lot of floppy disks. Most newer laptops no longer have floppy drives, but you can buy a modular one and swap it out when you need it. The best part is that on most laptops, these drives are hot-swappable meaning you don't have to turn off the computer to switch components. Some laptops suggest that you use Window's "Safely Remove Hardware" feature if swapping drives with the power on. The icon for this tool is in the system tray.

Displays:

                Laptops use built-in LCD screens which are typically between 12 and 17 inches, although there are larger ones available including widescreen formats (see the Toshiba Satellite picture at the top of this article for an example of this). Most laptops have the capability to connect a larger CRT or LCD monitor as well.

 Laptop LCDs can be classified by whether or not they use Thin Film Resistors (TFT, AKA Active Matrix) or are Passive Matrix. The older passive matrix LCD screens uses a grid of wires to produce the image on the screen. Dual-scan passive matrix improved refresh performance, but has been replaced with TFT technology which uses a transistor for each individual pixel instead of wires for the rows and columns.

 Below is a table of the various laptop display standards in use with their aspect ratio and resolution. If you need more background on video, read the Multimedia tutorial located in Domain 1.0 of this guide.

                LCD screens come in Matte Finish and High Gloss finish varieties. High gloss versions are newer and provide better contrast and brighter colors, but have more reflection.

Docking Stations and Port Replicators:

                This is a somewhat confusing topic as many people use these terms interchangeably, but there are subtle differences. The purpose of both of these devices is to add desktop functionality to a laptop. Let's take a look at the differences.

A docking station contains a mixture of ports, slots, drive bays and security features. It usually attaches to the notebook from underneath with a proprietary connection. Docking stations come in a variety of shapes, ranging from the same size as your notebook to much bigger. As the name implies, a docking station is where you park your notebook when you are at the office, or wherever it is you keep your docking station.

A port replicator, on the other hand, is a smaller, stripped down version of a docking station that mainly features the ports that you would find on a typical desktop PC, but lacks drive bays and slots. Port replicators typically connect via a USB connection.

 These devices are only commonly needed in a couple of different situations. The first is if you have a legacy peripherals that your laptop doesn't have ports for such as a parallel port. The other situation might be if you have an ultralight laptop that lacks the ports or drives included on larger laptops. With most laptops, modular drive bays, PCMCIA slots, and USB ports make it possible to connect or add just about any device needed without a docking station or port replicator.

PCMCIA:

The PCMCIA bus was developed for smaller computing devices and is hot-swappable. PCMCIA cards, now referred to as PC Cards (although CompTIA still uses the term PCMCIA), are very thin and provide connectivity for everything from removable media to ethernet connections. There are 2 types of PC Cards - 16-bit and 32-bit. Let's take a look at each of these:

16-bit - This obselete version of PC Card only supported 2 functions per card (i.e. modem and ethernet connection) at a throughput of 160 Mbps. These cards can be used in 32-bit slots.

32-bit - Also known as CardBus, this type comprises almost all of the PC Card slots you will come across. These cards support up to 8 functions on one card and provide a throughput of 1056 Mbps. 32-bit do not work in 16-bit slots.

 Both of these PC Card types have 3 sub types as follows:

Type I - 3.3mm thick and used as memory expansion units.

Type II - 5mm thick and supports most expansion functions except removable hard drives. Type I cards will work in them.

Type III - 10.5mm thick and used mainly for removable drives. Type I and II cards will work in them.

Express Card:

                On newer laptops, the PC Card standard is being replaced by a serial version called ExpressCard. These cards are smaller and are not backward compatible with PC Cards. ExpressCards use either the USB bus at speeds up to 480 Mbps or the PCIe bus at speeds up to 2.5 Gbps. They come in 34mm or 54mm width sizes with the 54mm versions missing a corner (see picture above). The thickness is 5mm (same as a type II CardBus card).

Mini PCI:

                Mini PCI is a version of the PCI bus for laptops. Although most laptops come with most ports needed and their functionality can be expanded using PC Card and ExpressCard devices, there are some occasions when you might want to upgrade a component in a laptop. For example, when the next generation of wi-fi becomes standard, it will likely provide better security and speed. To take advantage of this, you may want to swap out the wi-fi PCI card in the laptop. The image to the right shows a mini PCI wi-fi adapter.

Laptop Control Devices:

On a desktop PC, we use a mouse and keyboard to input our wishes into the computer. On a laptop, the keyboard is built in and you can certainly attach an external mouse. But laptops come with built-in mouse-like devices. There are 2 basic types commonly used today as follows:

                The older of the 2 types is called TrackPoint and was invented by IBM. TrackPoint uses a small pencil eraser sized "nub" to move the computer cursor around. This "nub" is usually located in the middle of the keyboard (blue dot in right image) and acts much like a joystick does. The functionality of a mouse's left and right click buttons are provided by 2 buttons below the space bar.

The second type is called a touchpad. Touchpads provide a small touch-sensitive pad located just below the spacebar on the keyboard. Moving your finger across the touchpad moves the cursor on the screen. Below the touchpad are the 2 buttons that act like a mouse's left and right click buttons. Touchpads are typically provided on larger sized laptops that have room to include them. Some laptops provide a TrackPoint device as well as a touchpad.

Function Keys:

 Laptops come with a special function key (Fn) that is located where the Windows key is located on desktop keyboards. The Fn key is pressed in combination with one of the F1-F12 function keys to

perform various tasks such as adjusting the screen brightness, disabling wi-fi, and other tasks. These tasks vary by manufacturer. Here are a couple of examples from a Toshiba laptop.

 Fn + F2 displays the power level of the batteries.

 Fn + F5 allows us to select the video output device.

2.2 Other Portable Devices

Contents:

§  Introduction

§  Tablet PCs

§  Personal Digital Assistants

Introduction:

Laptops certainly aren't the only portable devices on the market and they certainly aren't the smallest. There are a wide variety of portable options available today, many of them providing some of the functionality of a computer. For example, an iPod can store music, contacts, photos, etc., however, these types of devices will not be covered by the exam because they aren't full-fledged computing devices. In this section, we are going to cover the devices that are essentially mini computers.

Tablet PCs:

Tablet PCs come in 2 different form factors called Convertible and Slate (see right images). Slate varieties are flat and thin much like a tablet of paper. Convertible varieties can be configured just like a laptop or have the screen folded on top of the keyboard so that it resembles the slate variety. These devices have many of the same ports and slots that a laptop does. Many will have USB and/or firewire ports, PC Card or ExpressCard slots, and ethernet connection. Most tablet PCs have Bluetooth and WiFi capabilities as well. What you won't find on most of these devices is an internal optical drive.

 You may be wondering how these devices function without a mouse and keyboard. Tablet PCs use a device called a digitizer which is usually located behind the LCD screen. This input device allows you to interact with the screen using a special pen called a stylus. There are a couple of different digitizer technologies available as follows:

Active Digitizer - In most current tablet PC's, an active digitizer is used. An active digitizer, used in most tablet PCs, can track the position of the pen when it is in proximity to the digitizer. This feature allows the user to "hover" over items on the screen. This can provide helpful functionality such as the ability to view tooltips and auto-hidden items, and to navigate through menus without accidentally activating an item. The advantage of using active digitizer is that only movement of the stylus affects the mouse pointer and ignores other contact like your hand on the screen.

Passive Digitizer - Passive digitizers are also known as touchscreens. This type only knows where the position of the finger is when the user presses down on it. This causes the pointer on the screen to jump to the location of the press and instantly "click". Passive digitizers are either capacitive or resistive. The capacitive touch screen panel is coated with a material that stores electrical charges. When the panel is touched, a small amount of charge is drawn from the point of contact (the finger). Circuits located at each corner of the panel measure the charge and send the information to the controller for processing. Capacitive touch screen panels must be touched with an unprotected finger. The resistive touchscreen panel is coated with a thin metallic electrically conductive and resistive layer that causes change in the electrical current which is registered as a touch event and sent to the controller for processing. The resistive touchscreen panel can be operated by fingertip, stylus, and does not need direct skin contact in order to operate. Both capacitive and resistive touchscreens offer lower accuracy and a higher rate of error such as the case when a user's hand rests on the screen surface. This makes them less common in tablet PCs.

 Tablet PCs are fully functioning computers that can run an operating system such as Windows XP Tablet PC Edition. What makes this operating system very different is that it allows the user input data by either tapping keys on a virtual keyboard (on screen), or writing in a special window which is converted to text using character recognition software. Speech recognition is also being used with tablet PCs.

 Tablet PCs offer another form of input called Digital Ink. Digital ink allows you to draw or write on the screen without the tablet trying to convert it to text or interpretting it as a click or double-click. This is useful if you want sketch a diagram or take some quick notes, for example.

Personal Digital Assistants:

Also known as PDAs, these devices are similar in some respects to tablet PCs, but are much smaller - most of them being handheld size. Input to a PDA is similar to that of a tablet PC. They use a stylus and a touch screen that is similar to a passive digitizer in behavior. They also include a virtual keyboard, can use character recognition, or digital ink as input methods just like tablet PCs.

 PDAs use memory sticks like a digital camera. The most commonly used types now are MiniSD and MicroSD which are smaller versions of the SD standard that are commonly used in cell phones.

 PDAs run special operating systems which include Microsoft Windows CE, PalmOS, PocketPC, and some even run Linux. Most of these operating systems have the capability to sync with your computer. They either come with a cradle that is connected to the computer via a USB port (usually), or they sync via bluetooth. When you place the PDA in a cradle, it not only charges the device, but syncs the information with that on your computer. For example, let's say you met an old friend and added their contact information into the contacts on your PDA. When you place it in the cradle (or connect via bluetooth), that contact will be added to your contacts in Microsoft Outlook (for example). If you add a contact in Outlook, it will sync to your PDA as well.

 Most PDAs have a built-in infrared port that is used for "beaming" which allows you to wirelessly transfer data from one PDA to another. For example, this would allow you to beam a picture from your PDA to a friend's. The limitation of this is that infrared has a limited range so you have to be pretty close to the other PDA (i.e. same room).

 Many cell phones are now providing PDA-like features, many of which even provide email and web browsing through the cell phone network.

2.3 Troubleshooting Portable Devices

This section will provide a list of some troubleshooting tips that are specific to portable devices.

 If a laptop or tablet PC does not power on, first makes sure you have it plugged into a wall outlet. If it still won't power on and none of the LEDs on it light up, try plugging another device into the outlet to make sure the outlet is good. If that works, then try removing any peripheral devices such as USB, FireWire, smart cards, Express Cards, PC Cards, etc. If it still won't boot, try replacing the AC adapter. Make sure that you get one that meets the specs of your laptop or you could damage it.

 If your laptop battery discharges very quickly or will not charge all the way, replace it.

 If a PDA won't power on, make sure that the battery is charged (most don't come with AC adapters).

 If you are having problems with a WiFi connection on a laptop, make sure that the physical switch on the back or side of the laptop is on. Not all laptops have these switches to turn on WiFi, but many do. If your laptop has a Fn key combination for enabling wireless networking, check to make sure it is enabled.

 If your PDA or tablet PC is no longer recognizing handwriting, you probably need to calibrate the digitizer.

 If the touch pad on a laptop isn't working, make sure it hasn't been disabled via a Fn key combination, or utility provided by the manufacturer.

 If you are getting strange output when typing on your laptop, check to make sure that you haven't accidentally enabled an overlay via the Fn key. Some laptops come with overlays that fit on top of the keyboard and are activated using a Fn key combination. As an example, my Toshiba laptop has a 10-key overlay that is activated by pressing Fn + F9.

 If the keyboard isn't working at all, the keypad connector may have been disconnected.

 If you aren't getting any sound on a PDA or laptop, make sure the sound is not only turned up in the operating system, but on the device as well.

Thank You

3.1 Operating System Basics

Contents:

§  Introduction

§  What is an Operating System?

§  Introduction to Unix

§  Introduction to Linux

§  Introduction to OS X

§  Introduction to Windows

Introduction:

 This section will provide a brief introduction to UNIX, Linux, Mac OS, and Windows operating systems. The A+ exams will focus mainly on Windows as will this guide.

What is an Operating System:

                An operating system is a program that is loaded into the computer on boot up that is responsible for running other applications and provides an interface with which to interact with other programs. This interface can be mainly command-line based like Linux or Unix, or can primarily revolve around a Graphical User Interface (GUI) such as Windows and Macintosh operating systems.

 Operating Systems can be divided into 2 groups: Single-process and multiprocess. Single process operating systems are capable of working on 1 task at a time while a multiprocess OS can work on several processes at once by breaking tasks into threads. There are several terms related to multiprocessing systems that you will need to know as follows:

                          Multitasking - This is the ability to work on several different tasks at a time. This is accomplished by switching back and forth between the tasks. There are a few different types of multitasking:

Task Switching - Allows for multiple applications to be run at the same time. The window that is in the foreground is the active window while the other applications run in the background. Used in Windows 3.0.

Cooperative Multitasking - Applications can control the system resource until they are finished. When the hourglass is displayed on the screen, you would be unable to perform any tasks until the system had finished the task that it was working on. If a task caused faults or other problems, it would cause the system to become unstable and force a reboot. Used in Windows 3.x.

Preemptive Multitasking - Applications are allowed to run for a specified period of time depending on how important the application is to the operation of the system(priority basis). This means that even though you may see an hourglass on the screen, you can still launch or use other application at the same time. If a particular task is causing problems or faults, that application can be stopped without the system becoming unstable. Used in Windows 9.x.

Multiuser - This is similar to multitasking and is the ability for multiple users to access resources at the same time. The OS switches back and forth between users.

Multiprocessor - Having multiple processors installed in a system such that tasks are divided between them.

Introduction to UNIX:

                Originally developed in 1969 by AT&T employees, UNIX was the operating system of choice for decades and is the oldest of the bunch. Traditionally, it was command line based although newer versions do have a graphical user interface (GUI) like Windows. Solaris by Sun Microsystems is the most popular version of UNIX in use, although HP-UX and AIX still have some market share. UNIX is used as an operating system on servers and for specialty applications. It is not typically used for personal computing.

Introduction to Linux:

 Linux is a UNIX-like operating system, that was invented by Linus Torvalds in 1991. Although it is a lot like UNIX, it is open source which means that the operating system and source code are freely available including most supporting applications which are freely licensed under the GNU public license. Because the source code is freely available, various organizations have modified the code and created their own variations known as "distributions". Some of the more common ones are Red Hat, SuSE, Debian, and Fedora Core. Linux has become a very popular platform for servers, particularly web servers. It also has a wide variety of GUIs that can be used for personal computing.

Introduction to OS X:

                Macintosh computers produced by Apple are proprietary systems that run Mac OS operating systems. Mac OS X is the successor to the original Mac OS, which had been Apple's primary operating system since 1984. Unlike its predecessor, Mac OS X is a Unix-like OS based on BSD. Beginning in 2006, Macs began running on Intel CPUs for the first time instead of their own proprietary hardware.

Introduction to Windows:

                Microsoft leads the operating system market with their Windows series of operating systems. At the time of this writing, Windows XP, Windows 2000, and Windows 2003 Server are currently the most widely used versions, although Windows Vista was recently released. The A+ exam probably will not test you on Windows vista. It is also doubtful that you will be tested on Windows 9x or NT with the exception of performing upgrades.

                There are several major components that are essentially the same in most versions of Windows (2000/2003/XP) that you should know how to get to and use.

 Windows Explorer is the utility used for file management functions in Windows operating systems. It can be used to move, copy, rename, delete files and browse through the directory. Explorer displays the file structure in a hierarchical tree. The figure below shows the explorer interface.

 There are several ways in which explorer can be launched including right clicking "My Computer" and selecting explore or clicking the "Start" button and selecting run and type in "explorer". For the exam, you will need to know how to navigate and use Windows Explorer.

       The "My Computer" icon is located on the desktop and allows you to browse through the file structure and set many of the file and folder properties. When My Computer is opened, you will see a window similar to the one shown below.

 One of the most important parts of My Computer is the folder options that can be accessed from the view menu. Folder options has 3 tabs where various setting can be configured as follows.

 The general tab allows you to configure how folders and files appear. The View tab allows you to set a variety of file and folder options. One of the most common of these is to check the "Show All Files" radio button in order to allow hidden files to be shown. You should be familiar with these settings for the exam.

 The offline files tab allows you to configure the computer to synchronize files on a network. This is mostly used with laptop computers. The File Types tab allows you to control which applications open specific file types. This is otherwise known as associations which can also be controlled by using the WINFILE.EXE program in Windows 9x.

 Shortcuts can be created when browsing the file system from the file menu and selecting "new" then "shortcut". They can also be created in Windows Explorer or by right clicking a file and selecting "Create Shortcut" from the drop down menu. New folders can be created in the same manners.

 The Windows Control Panel is where most hardware, software and networking settings are configured. The Windows XP control panel is shown below. This is the default "Category View" that is new in Windows XP. Notice in the upper left side there is a link to switch to classic view which is the more familiar version found in previous Windows operating systems. You will need to be familiar with using the control panel for the exam and know the various ways to access them. For example, the Network control panel can also be accessed by clicking on the Network Neighborhood (called "My Network Places" in Windows XP) and selecting "Properties" and the Display control panel can also be access by clicking on the Desktop and selecting "Properties".

 The System Properties control panel is one of the key control panels that is used to configure the systems hardware settings. Windows 95/98/2000/XP System Properties contain a portion called "Device Manager" that can be used to update device drivers, modify IRQ and I/O settings and troubleshoot hardware conflicts. A red "X" next to a device denotes that the device is either disabled or is experiencing a conflict. Windows NT did not include a Device Manager which is shown below. Windows NT/2000 system properties are where user and hardware profiles are configured.

Note that you can also get to the System Properties by right clicking on the "My Computer" icon and selecting properties. In Windows 2000 and XP, the Device Manager looks slightly different and can be accessed via the Computer Management Console. Device Manager can be navigated using the arrow keys if the mouse is not working. In the image above, you will also see the Performance tab. This is where file system, virtual memory and graphics settings can be configured.

 The desktop is the first "screen" that you see after Windows loads. All of the icons on the desktop are shortcuts to other files and applications. You should be familiar with the Desktop and know that it is actually located in C:\Windows\Desktop for Windows 9x and C:\Documents and Settings\username\Desktop in Windows 2000 and XP. Below the desktop is the taskbar that contains toolbars, the start menu and displays active windows.

 If you right click on the Desktop and select Properties, you will bring up the Display Properties for your system as shown below. From here you can customize Windows' colors and appearance, screensavers, screen resolution, default font sizes, and more.

 The start menu is the starting point for most tasks that are performed on a Windows computer. The Windows XP default start menu is different than previous versions of Windows and is pictured below. Like many things in XP, the start menu can be switched to classic mode and will appear like previous start menus. In addition to changing the menu, this setting will also put the My Computer, My Network Places, and My Documents icons on your desktop.

                You will need to know how to navigate the start menu and which items can be accessed from here. Also make sure that you know how to use the "Run" feature in the start menu and how to bring up a command or DOS prompt from here. In Windows 9x, you would type COMMAND and enter. For Windows NT/2000/XP the command would be CMD.

 There are a number of keyboard shortcuts to know:

CTRL + ESC - Brings up the startmenu which can then be navigated with the arrow keys. Many keyboards have a Windows key that performs the same function.

ALT + ESC - Cycles through currently open windows.

ALT + TAB - Displays a menu of open applications that can be cycled through by continuing to hit the tab key.

SHIFT - Will bypass the autorun feature on a CD.

 These are just some of the Windows basics, but there is too much to cover all of it here. You need to make sure that you know your way around Windows and where to find various features, customizations and tools.

3.2 File Systems

Contents:

§  Introduction

§  Partitions

§  File Systems

§  Managing Drives

Introduction:

 In an operating system, the file system is the structure by which files are organized, stored, and named. The file system determines what features and controls you have with regards to the organization, maintenance, and security of your data. Different file systems handle this job differently and vary in the features that they support.

Partitions:

                Partitions are configurable logical storage units on your hard drive. Partitions and other storage units, allow you to divide a hard drive in order to better manage the organization of your data and applications. The following are common hard disk configurations.

Partition - A partition is a portion of a physical hard disk. A partition can be primary or extended

Primary Partition - This is a bootable partition. One primary partition can be made active.

Extended Partition - An extended partition is made from the free space on a hard disk and can be broken down into smaller logical drives. There can only be one of these per hard disk.

Logical Drive - These are a primary partition or portions of an extended partition that are assigned a drive letter.

Volume - This is a disk or part of a disk that is combined with space from the same or another disk to create one larger volume. This volume can be formatted and assigned a drive letter like a logical drive, but can span more than one hard disk. A volume set can be extended without starting over, however to make it smaller, the set must be deleted and re-created.

                There are various management tools that can be used to configure drives. The Disk Management MMC is a snap-in for the Computer Management Console in Windows 2000 and XP. You can create partitions, volume sets, logical drives, format disks, etc. NT 4.0 had a similar tool called the "Disk Administrator". DOS and Windows 9x utilize the FDISK utility.

                When discussing Windows file systems you need to understand what File Allocation Tables (FAT) are. FAT is a table that an operating system maintains in order to map the clusters (the smallest unit of storage) that a file has been stored in. When files are written to a hard disk, the files are stored in one or more clusters that may be spread out all over the hard disk. The table allows Windows to find the "pieces" of your file and reassemble them when you wish to open it.

File Systems:

                Once a drive has been partitioned the way you want, you then need to format it. Formatting is the process that installs the file system on the drive. There are several different types of file systems that are explained below:

FAT16 - FAT16 table entries are 16 bits in length limiting hard disk sizes to 2GB. Note that even if the OS supports larger partition sizes, the BIOS must also support logical block addressing (LBA) or the maximum partition that you will be able to create will be either 504 or 528 MB. This file system is no longer used.

FAT32 - Created to allow more efficient use of hard drive space. Although the FAT32 file system supports hard disks up to 2 terabytes in size, some hard disks may not be able to contain bootable partitions that are larger than 7.8 GB because of BIOS limitations (must support the INT13 interface). In order to format a drive as FAT32, the "Large disk Support" must be enabled when starting FDISK. FAT32 is not compatible with older versions of Windows including Windows 95A and NT. In Windows 9.x, the CVT1.EXE can be used to convert FAT16 partitions to FAT32.

NTFS 4 - NTFS 4 is the file system used by Windows NT that provides increased security and reliability over other file systems. On an NTFS partition, you can't boot from a DOS boot disk - this is one of the security features of NTFS. Additionally, a floppy disk cannot be formatted as NTFS. For this reason it might not be a bad idea to have a small partition formatted FAT so that you can boot into DOS for recovery purposes. In order to convert a FAT partition to NTFS, NT includes a utility called convert.exe.

NTFS 5 - This is the native file system for Windows 2000, 2003, and XP. NTFS 5 has many new features as follows:

Encrypted File System(EFS) - Windows 2000, 2003, and XP NTFS volumes have the ability to encrypt data on the disk itself. Cipher.exe is a command line utility that allows for bulk or scripted file encryption.

Disk Quotas - Provides the ability to set space limitations on users on a per volume basis.

Defragmentation - Windows 2000 and XP include a disk defragmenter that can be used on NTFS partitions. Windows NT did not offer this.

Volume Mount Points - Provides the ability to add new volumes to the file system without having to assign a drive letter to them. This feature is only available on an NTFS partition.

Compression - In Windows 2000 and XP files, folders and entire drives can be compressed by right clicking on the item to be compressed and selecting "properties" and then "advanced".

 The convert.exe utility can be used to convert a FAT or FAT32 partition to NTFS.

HPFS - Stands for High Performance File System and is used with OS/2 operating systems. This file system can only be accessed by Windows NT 3.51 and OS/2.

Managing Drives:

 In addition to the disk administration utilities previously mentioned, information about a drive can be displayed by right clicking the drive in My Computer or Windows Explorer and selecting "Properties". In a Windows XP system, a window like the one below will appear.

                Here you can view the amount of used and freespace on the drive, the capacity and the file system. The tools tab provides access to defragmentation, scandisk and backup utilities. The Sharing tab is for sharing the drive and setting share-level permissions on it so that it can be accessed across the network. The security tab allows you to configure local file permissions and the quota tab allows you to set disk quotas which limit the amount of disk space that a user can use.

 Backing up drives allows you to recover your data or even the entire system if a catastrophe occurs. There are several different types of backup:

Full - copies all files and marks them as being backed up.

Incremental - copies only files created/changed since last full backup and marks them as being backed up.

Differential - copies only files created/changed since last full backup and doesn’t mark them as being backed up.

Daily - copies only files created/changed today and doesn’t mark them as being backed up.

 In DOS backups can be run with the BACKUP command. There are several switches that can be added to the command.

/S - Forces all files and subdirectories to be backed up.

/M - Only modified files are backed up.

/D - Backs up files modified after a specific date.

/T - Backs up files modified after a specific time.

                The backup utility can be accessed via Start>Programs>Accessories>System Tools>Backup and also via right clicking on a drive in My Computer and selecting the tools tab as previously mentioned. In Windows 2000/2003/XP, backup can also be launched by entering ntbackup in a "Run" dialogue box.

 There are several different hard drive utilities that can be found in the various versions of Windows that are listed below:

CHKDSK - Performs the same functions as SCANDISK did in previous Windows versions, but is for Windows 2000/2003/XP.

DEFRAG - Reorganizes data on the disk for optimal disk performance. In DOS this utility was run from a DOS prompt. In Windows 2000, 2003, and XP this utility can still be run from a prompt or can be accessed at Start>Programs>Accessories>System Tools>Disk Defragmenter.

3.3WINDOWS XP OVERVIEW and INSTALLATIONS

Attended Installation of Windows XP Professional

This chapter covers attended installations of Windows XP Professional from a CD-ROM.

 Installing Windows XP Professional from a CD-ROM to a clean hard disk consists of these four stages:

§  Running the Setup program - Partitions and formats the hard disk (if required) for the installation to proceed and copies the files necessary to run the Setup Wizard.

§  Running the Setup Wizard - Requests setup information about the local workstation where the installation is taking place.

§  Networking components - Installs the networking components that allow the computer to communicate with other computers on the local network.

§  Completing the installation - This final phase copies files to the hard drive and configures the final stages of the setup.

                There are some noted differences in the Windows XP Professional installation and older Windows NT4 and Windows Professional installations.

                The design of the installation program assumes that your system has the ability to boot directly from a CD-ROM or that you will use a Windows 95/98/ME boot floppy to begin installing from a CD. The ability to directly create setup floppies has been dropped from Windows XP. Setup boot disks are available only by download from Microsoft. The Setup boot disks are available so that you can run Setup on computers that do not support a bootable CD-ROM.

 There are six Windows XP Setup boot floppy disks. These disks contain the files and drivers that are required to access the CD-ROM drive through generic PCI drivers and begin the Setup process.

 If your computer does support booting from a CD-ROM, or if network-based installation is available, Microsoft recommends that you use those installations methods.

 Setup will not prompt the user to specify the name of an installation folder unless you are performing an unattended installation or using winnt32 to perform a clean installation.

 By default, the Setup Wizard installs the Windows XP Professional operating system files in the WINDOWS folder. If this folder exists on the partition you have chosen for the install, setup will warn you that you are about to overwrite the current operating system installed on that partition. In order to keep it (e.g. dual or multi booting scenario) you would need to choose another partition for the installation.

 To start the Setup program, insert the Windows XP Professional installation CD-ROM in your CD-ROM drive

 If an operating system is detected on the hard drive, the following message will appear:

 In this scenario, you would need to press any key on the keyboard to continue with the CDROM installation.

 After the computer starts, a minimal version of Windows XP Professional is copied into memory. This version of Windows XP Professional starts the Setup program.

                After all of the files are copied and the system is restarted, the text-mode portion of Setup is started which prompts you to read and accept a licensing agreement.

You would select "F8-I agree" to continue. (If you elect not to accept the agreement, the installation will end)

                You are then prompted to select a partition on which to install Windows XP Professional. You can select an existing partition or create a new partition by using any unpartitioned free space on the hard drive(s).

 (The above example shows a partitioned and formatted drive)

 Once a partition has been selected the next step is to select a file system for the new partition. Next, Setup formats the partition with the selected file system. (This would assume that a file system didn't currently exist. In this example, one already does and it is formatted in NTFS so I have elected to leave it as is. Any formatting done here during setup will destroy any existing data on the partitions formatted.)

 From here Setup copies files to the hard disk and saves configuration information.

 Setup restarts the computer once the file copy is completed and then starts the Windows XP Professional Setup Wizard, the graphical user interface (GUI) portion of Setup.

 The GUI-based Windows XP Professional Setup Wizard is the next stage of the installation process.

Regional settings - In this section you are able to customize settings to your language and where you live as well as setup Windows XP Professional to use multiple languages and regional settings.

Personalize your Software - In this section you can enter the name of the person and the organization to which this copy of Windows XP Professional is licensed. This can be your own name and nothing in the organization field or the name of the company in both places if this installation is being performed in a place of business. Software installed on the system later will often use this information for product registration and document identification.

Your Product Key - This page is where you enter your 25-character product key in order to install the software.

 If you incorrectly type the key, an error message will be generated.

Computer Name And Administrator Password - Here you enter a name for the computer or use the auto generated one that Windows XP Professional provided.

 The computer name will always display in all uppercase letters, no matter how you type it. The name is not case sensitive.

                In the Administrator Password box on the same screen, you will enter the password to be used for the administrator account and in the Confirm Password box you will re-enter it to make sure that it is entered correctly.

 If the passwords do not match, the above error message will appear and you will need to enter them again.

Modem Dialing Information - This section will begin only if an installed modem has been found on your system.

 Enter the correct country or region if it is not selected. (It should match your selection from the Regional settings page.) Type your area code or city code and any number you might need to dial to get an outside line. You can also select either tone or pulse dialing on this page as well.

Date and Time Settings - This section of Setup allows you to verify that the correct date, time and time zone are entered and whether or not the system should adjust itself automatically at the daylight savings times events each year.

Network Settings - The next section of setup deals entirely with installing the Windows XP Professional networking components on your system.

                Installing Windows XP Professional networking components involves the following processes:

Detect network adapter cards - The Setup Wizard detects and configures any network adapter cards installed on the computer. By default, it attempts to locate a DHCP server on the network. If none is found it will use an Automatic Private IP Addressing (APIPA) IP address. (The APIPA IP address feature of Windows XP Professional automatically configures a unique IP address from the range 169.254.0.1 to 169.254.255.255 and a subnet mask of 255.255.0.0 when TCP/IP is configured for dynamic addressing and a DHCP server is not available.)

Select networking components - The Setup Wizard prompts you to choose typical or customized settings for networking components.

 The Typical (selected by default) installation includes the following options:

Client For Microsoft Networks. Allows your computer to access network resources.

File And Printer Sharing For Microsoft Networks. Allows other computers to access file and print resources on your computer.

QoS Packet Scheduler. Helps provide a guaranteed delivery system for network traffic, such as Internet Protocol (TCP/IP) packets.

Internet Protocol (TCP/IP). Allows your computer to communicate over local area networks (LANs) and wide area networks (WANs). TCP/IP is the default networking protocol.

                You can install other clients, services, and network protocols during the Windows XP Professional installation by choosing CUSTOM, but it is recommended that you wait until after the installation has completed to add additional services. (The exception would be if the lack of these services would prevent the system from coming online to your network properly upon restart.)

Workgroup or Computer Domain - This section allows you to choose to join a domain for which you have administrative privileges or to join a local workgroup. You can create the computer account in the domain you are joining ahead of time or during installation. (The Setup Wizard prompts you for the name and password of a user account with authority to add domain computer accounts if you elect to create the account during the Windows XP Professional installation).

                After installing the networking components, Setup starts the final steps of the installation process, which include:

Installs Start menu items - Shortcuts that will appear on the Start menu are installed and configured during this stage.

Registers components - The configuration settings that you specified earlier during the install are configured now.

Saves the configuration - The Setup Wizard saves your entered configuration settings. Once the system is restarted, the computer uses this configuration by default.

Removes temporary files - Any files used by the Setup Wizard that are no longer needed are deleted.

Restarts the computer - The computer is automatically restarted. This is the final step of the Setup Wizard.

                Upon restart, the computer will either boot directly to Windows XP Professional or it will bring up the operating system selection window (the text of the BOOT.INI file) if you have more than one operating system installed.

 After you start Windows XP for the first time, you will come to the Welcome to Microsoft Windows screen to finish setting up your computer. Click on the Green NEXT arrow at the bottom right hand corner of the display.

                The system will then check to see how you will connect to the Internet. If Windows cannot detect the settings it will prompt you for input. (You can also select SKIP to by pass this section).

                The Registration of your Windows XP Professional software IS NOT REQUIRED. You can skip this step and never go back to it.

                The Windows Product Activation screen appears next. Windows Product Activation has been designed by Microsoft it protect their intellectual property as much as possible from software piracy. According to Microsoft through the setup feature, you do not need to send any information at all when you activate the product, not even a name. This step is required, at this time or within the first 30 days.

                If you decide to skip this registration step now, you will only be able to use Windows XP Professional for 30 days. At that time, the operating system will not function without activating the product. You will have no other option but to either blow the partition away and reinstall the OS for another 30 days or activate the software.

                If you skip this step, Windows XP will periodically remind us during our 30-day period to Activate the product.

                The next screen we are brought to is the Internet Access screen, which allows us to configure our Internet connection at this time as well. You do have the option to skip this step as well.

                The next screen that appears is the User Setup screen. On this setup page you are able to enter the name of each person that will have local access to this computer. If you choose to do this now, Windows XP Professional would create a separate user account for each name entered.

                These names would first appear on the Welcome Screen in alphabetical order. At that point, users would be able to select their name from the Welcome screen to use the computer. The local administrator can use User Accounts in the system Control Panel to assign these users with passwords and system permission limits. It is also where additional users can be created, in lieu of doing here or in addition to entering some here.

                At least one name needs to be entered.

                This first user becomes a local administrator by default.

 Best of luck in your studies and please feel free to contact me with any questions on my article and remember, "If a bad guy can alter the operating system on your computer, it may not be your computer anymore"

Upgrading to Windows XP Professional

 Before we get started with a direct upgrade to Windows XP Professional we need to know which operating systems support a direct upgrade.

Windows XP Supported Upgrade Paths

                The following direct upgrade paths are supported by Microsoft and are considered viable for both the Windows XP Professional and Windows XP Home operating systems.

Microsoft Windows 98

Microsoft Windows 98 Second Edition

Microsoft Windows Millennium Edition

·         Windows XP Home Edition Retail (Full) Version

·         Windows XP Home Edition Upgrade Version

·         Windows XP Professional Retail (Full) Version

·         Windows XP Professional Upgrade Version

Microsoft Windows NT 4.0 Workstation

·         Windows XP Professional Retail (Full) Version

·         Windows XP Professional Upgrade Version

Microsoft Windows 2000 Professional

·         Windows XP Professional Retail (Full) Version

·         Windows XP Professional Upgrade Version

Microsoft Windows XP Home Edition

·         Windows XP Professional Retail (Full) Version

·         Windows XP Professional Upgrade Version

                All Versions of Windows NT 4.0 require Service Pack 5 to be installed prior to upgrading to Windows XP.

                Currently, there are no supported direct upgrade paths for the following Microsoft operating systems:

Microsoft Windows 3.x

Microsoft Windows NT 3.51 Workstation

Microsoft Windows NT 3.51 Server

Microsoft Windows NT 3.51 Server with Citrix

Microsoft Windows 95

Microsoft BackOffice Small Business Server

 Having this information available or knowing where to look it up is important before you get started.

[NOTES FROM THE FIELD] - I often get the question, "how do you know all of this stuff", when I am working with desktop or system admins. The truth is, I often do not know the information off the top of my head. Sometimes I do, and it is often due to the fact that many people throughout the course of the year come to ask me different questions and because many of them are repetitive I often have immediate recall of them. Many times, (more often than not) I don't remember the answer, but I have a vague idea of where I looked it up when I was asked it before and I head right "battle" is knowing where to look up the information when you need it. If you can do that, you're ahead of the game and ahead of most other people you might work with.

                Once you are certain that the operating system you're currently using can be directly upgraded to Windows XP Professional, you then need to be sure that the installed system hardware meets the minimum Windows XP Professional hardware requirements by verifying all of the hardware is on theHardware Compatibility List (HCL) at the Microsoft website.

                Windows XP Professional supports only the devices listed in the HCL. If your hardware isn't listed, contact the hardware manufacturer and request a Windows XP Professional driver.

                Support means that while the operating system may load and run on unsupported hardware and software, any issues that come up with the system will not be covered (i.e. supported) by Microsoft Technical Support if you should need to engage them.

                You can test the computer for compatibility by using the Windows XP Professional Compatibility tool. During a system upgrade you will see the option for this on the introductory screen. (You also run the tool from the command line by typing <CDROM DRIVE>:\i386\winnt32 /checkupgradeonly. You can perform just the check and then exit the tool without installing the operating system, if you wish.)

                If you have AUTORUN enabled on your system the Welcome to Microsoft Windows XP setup screen will appear.

                The Windows XP Professional Compatibility tool can be run by selecting Check system compatibility and then Check my system automatically.

                If any issues are found they will be reported in the Microsoft Windows Upgrade Advisor Compatibility window.

                During an OS upgrade on a system with pre-installed software, you can use upgrade packs to make the existing software compatible with Windows XP Professional. Upgrade packs are usually available from the appropriate software manufacturers. You can also get updated setup files from Microsoft during the upgrade installation if you are connected to the internet.

                As time passes from the point of original software distribution, (many vendors often call the first official release of a software platform as a GOLD distribution) many files may be updated before a Second edition of the software (such as Windows 98 Second Edition) or a service release (Office XP Professional SR1.) is distributed. Dynamic update allows you to do this as you start your installation. You can also elect to not perform it during the installation, in order to do so at a later time.

                The next point of the Upgrade installation is the setup type. Even though you are within an existing operating system, you are not forced to upgrade to the new operating system. You can choose the option to perform a clean installation at this point. (The default recommended option is Upgrade, as shown above.)

                The next page is the License Agreement, where you will need to click I Accept This Agreement, in order to continue.

                Next, you will need to enter your 25-character product key on the product Key page.

                The next phase from here will vary slightly depending on whether you are upgrading from a Windows 9x system, where you will be asked whether you want to upgrade to the NTFS file system from your FAT or FAT32 partition, or if you are upgrading from Windows NT4 and already using NTFS, you will be displayed with the Upgrading To The Windows XP Professional NTFS File System page.

                After you choose how you wish to handle the file system upgrade, setup will continue, reboot the computer and finish the upgrade of your system on its own.

Thank You