Partitions, logical drives and formatting

Partitions, logical drives and formatting _________

People often get partitions and logical drives mixed up. Partitions and logical drives are set up with fdisk.

A logical drive is not a hard drive, but how a single hard drive can be assigned several drive letters. Logical drives are also called volumes.

The drive letters a: and b: are reserved for floppy drives and cannot be given to anything else.

For example, if you have a pc with windows 95 as an operating system and open my computer to see the following drive letters:

a: c: d:

The pc has one floppy drive (a:), a hard drive with a single partition (c:) and a cd-rom or dvd-rom (d:).

The partition which contains the operating system is defined as the active partition, and is also referred to as the primary partition.

If, on another windows 95 pc has the following drive letters:

a: c: d: e:

The pc has one floppy drive (a:), a primary/active partition (c:), an extended partition with one logical drive (d:) and one cd-rom or dvd-rom (e:).

The extended partition is sub-divided into logical drives. you can have one logical drive in your extended partition or up to a maximum of 23. Though if you do have 23 logical drives in your extended partition, you will not be allowed to have a cd-rom/dvd-rom or install any further hard drives as all your drive letters will have been allocated.

Partitions and logical drives must be set using fdisk before they can be formatted. Formatting is also called logical formatting.

The size of the volumes will be dictated by the format command. FAT volumes are a maximum size of 2gb and FAT32 volumes are a maximum size of 2tb (terabytes).

The DOS command lastdrive is required in the config.sys file is you are using dos on your pc, as the default number of logical drives is set to five. As a: and b: are reserved for floppy drives and therefore automatically set, and the first drive letter of a hard drive is c:, it means that e: will be the last volume seen by DOS. Anymore than three logical drives on a hard drive, or two logical drives if use a cd-rom that can be seen by dos, must have the lastdrive set in config.sys.

2) Windows NT is one of the o/s covered in the exam. It may be an old o/s, but not all businesses upgrade either their hardware, software or o/s everytime there is a new version released.

NT differs from Windows 2000 in many ways. You may actually be questioned on some of those differences.

If you were able to get hold of both of these o/s they would be great additions to your lab, and will also help network+ certification if you choose to take it.

Dual-booting and multi-booting is a great thing to have in your lab, especially if you only have one pc, to gain experience with several operating systems.

Because NTwill not recognise FAT32 partitions and logical drives, it is important that if Windows 95 or 98 is the original o/s on your pc that it is installed on a FAT partition and not FAT32.

FAT can be changed to FAT32 via Drive Converter, but it cannot be changed back.

As NT will not see the FAT32 partition as it is being installed, it will see a partitioned but unformatted drive and format it to FAT - hence deleting your previous version of windows.

3) A sector is always 512 bytes, which is half a kilobyte.

A cluster (also known as allocation units) is the smallest unit of disk that the operating system knows how to handle when writing files and is made up of a number of sectors.

Logical formatting creates a file allocation table (FAT) and defines the minimum number of sectors a cluster can use to store data. The number of clusters is dictated by the format. FAT16 has 65,525 and FAT32 has a maximum of 268,435,456. They typically vary in size between 2k and 32k, depending on the size of the volume. The FAT is a record of which files are contained in which clusters. For instance, if a file is 32k in size it will take up 8 clusters, if the clusters are 4k in size. Regular defragging of a drive ensures that these clusters are continuous.

The more sectors a cluster has, the lesser the demands are on the FAT.

Partition size....Recommended file system / cluster size 1-16M..............FAT-12 / 4K 16-256M..........FAT-16 / 4K 256-512M........FAT-16 / 8K 512M-1G..........FAT-16 / 16K or FAT-32 / 4K 1-8G...............FAT-32 / 4K 8G and up........FAT-32 / 8K

4) SCSIThe SCSI (pronounced "scuzzy") interface is mostly used to connect mass-storage devices such as hard disk drives, tape devices and CD-drives but is also often used to connect scanners and other optical devices. SCSI devices can be internal or external.The advantages are that it is fast, reliable, it allows you to connect multiple devices in a chain and it is easily expandable.

TerminationSCSI chains must be terminated using terminators on both internal and external ends to prevent the signal from echoing.Most internal SCSI devices have built-in termination, external devices often have to be terminated using a terminator.

SCSI IDs and LUNsEvery device in the chain must have a unique ID assigned so the host adapter will know with who it's communicating.(When using Logical Unit Numbers (LUNs) a single SCSI ID can support multiple devices, this is often used in hardware-raid arrays.)The lowest ID is 0 (often preset on host adapter to be used for bootable hard disk drive.) and the highest is 7 or 15 (depending on the flavor, see table below.)The host adapter often is preset to ID 7.

The higher the SCSI ID , the higher the priority when negotiating for the SCSI bus. 7 is highest for all SCSI types, priority sequence for wide SCSI is: 7, 6, 5, 4, 3, 2, 1, 0, 15, 14, 13, 12, 11, 10, 9, 8.

On older devices SCSI IDs are configured by setting jumpers or switches on the device. This is a fairly simple process:For example, if you have 3 jumpers to configure the ID and you want the device to use ID 4 you will need to think in 'bits'.3 jumpers (bits) allow for a maximum value of 7:(jumpers) on on on = (bits) 1 1 1 = (ID) 4+2+1 = 7If you would set the first and third jumper only, the ID 5 will be used (4+0+1=5).You need to know this for the exam, see the exam objectives at the bottom of this page.

SCSI ID SCSI-2 Jumper or switches 0 0 0 0 off / off / off 1 0 0 1 off / off / on 2 0 1 0 off / on / off 3 0 1 1 off / on / on 4 1 0 0 on/ off / off 5 1 0 1 on / off / on 6 1 1 0 on / on / off 7 1 1 1 on / on / on SCAM (SCSI Auto-Magically), found on SCSI-3 and many SCSI-2 host adapters is a feature that assigns SCSI IDs dynamically and resolves conflicts automatically.

CablingSCSI uses different types of cabling and connectors.- Internal devices use a flat ribbon cable with a 50 or 68-pin connector.- External devices use a rather thick cable with a 50 or 68-pin connector.Narrows SCSI (8-bit) uses the 50-pin connector and Wide SCSI (16-bit) uses the 68-pin connector.

Expansion slotsSCSI host adapters have been made for all of the common I/O buses, including ISA, EISA, VLB, MCA and PCI.PCI is the most common used today.

SCSI TypesThere are many different flavors of SCSI, the most important differences are max through-put, bus width and speed, and maximum supported number of devices. Refer to the table below and notice their differences. Mode Specification # of Devices* Bus Width Bus Speed Through-put** AsynchronousSCSI SCSI-1 8 8 bits 5 MHz 4 MB/s SynchronousSCSI SCSI-1 8 8 bits 5 MHz 5 MB/s FastSCSI SCSI-2 8 8 bits 10 MHz 10 MB/s WideSCSI SCSI-2 16 16 bits 5 MHz 10 MB/s Fast/WideSCSI SCSI-2 16 16 bits 10 MHz 20 MB/s UltraSCSI SCSI-3SPI 8 8 bits 20 MHz 20 MB/s Ultra/WideSCSI SCSI-3SPI 16 16 bits 20 MHz 40 MB/s Ultra2SCSI SCSI-3SPI-2 8 8 bits 40 MHz 40 MB/s Ultra2/WideSCSI SCSI-3SPI-2 16 16 bits 40 MHz 80 MB/s Ultra3SCSI SCSI-3SPI-3 16 16 bits 40 MHz 160 MB/s * The number of devices includes the host adapter, so you'll have 7 or 15 devices left ;)** This is the maximum through-put for the whole chain, not per device. Fast: Refers to bus speeds of 10 MHz, Ultra: Refers to bus speeds of 20 MHz, Ultra2: Refers to bus speeds of 40 MHz Wide: Refers to the bus width (16-bits). As you can see in the table below 'Wide' always supports 16 devices. (Since there is no 'narrow' version of Ultra3 SCSI the word Wide is omitted)

LVD: Low Voltage Differential Signaling is a technology first introduced in the SCSI-3 SPI-2 (Ultra2) specification to overcome cable length limitations when the bus speed was increased to 40 MHz and to allow for higher transfer speeds.

Current SCSI related exam objectives for the 2002 A+ Core exam.1.6 Identify proper procedures for installing and configuring SCSI devices.Content may include the following:- Address/Termination conflicts- Cabling- Types (example: regular, wide, ultra-wide)- Internal versus external- Expansion slots, EISA, ISA, PCI- Jumper block settings (binary equivalents)

4.3 Identify the most popular type of motherboards, their components, and their architecture (bus structures and power supplies).- SCSI (Wide, Fast, Ultra, LVD(Low Voltage Differential))

5)ATA/IDE/EIDE/SATAIntegrated Drive Electronics (IDE) is an interface used to connect internal storage devices such as hard disk and CD/DVD-ROM drives. The acronym 'IDE' first appeared in 1986 when Compaq, Western Digital, and a division of Control Data Corporation called Imprimis, were developing a hard disk drive with an integrated controller. Two years later a subgroup of the Common Access Method (CAM) committee was formed, which submitted a standard to the American National Standards Institute in late 1990 that was finally approved four years later. The specification's official name is AT Attachment (ATA), but we often still refer to the ATA specification as IDE. More and more manufacturers have started using the proper term ATA. Today the Technical Committee T13 is primarily responsible for all interface standards relating to the ATA interface.

Early PCs using the IDE interface had ISA expansion boards with an IDE connector. Most motherboards available today have multiple integrated IDE connectors. The first IDE devices were rather slow, using the 8-bit ISA interface the maximum data throughput was 4MBps, 16-bit IDE connections allowed up to 8 MBps. This first IDE/ATA standard has support for only one channel allowing a maximum of two hard disks. It supports PIO modes 0, 1, and 2, and single word DMA modes 0, 1, and 2, and multiword DMA mode 0.

PIO modes and DMA modes define different methods for the disk drive to communicate with the system. The older method Programmed I/O (PIO) requires the help of the CPU to transfer data between the disk and the system's memory. There are 5 different PIO modes listed in the following table along with their corresponding maximum transfer rates:

PIO ModeTransfer Rate (MBps)

Mode 0

3.3

Mode 15.2

Mode 28.3

Mode 311.1

Mode 416.7

DMA is short for Direct Memory Access. As it name implies, DMA allow direct access to the system's memory, bypassing the CPU. Single word DMA transfers a single word (2 bytes/16-bits) per transfer session, where multiword DMA sets up a transfer session and sends several words after each other, reducing the overhead per transfer session. The following table lists the different DMA modes along with their corresponding maximum transfer rates:

DMA ModeTransfer Rate (MBps)

Single word 0

2.1

Single word 14.2

Single word 28.3

Multiword 04.2

Multiword 113.3

Multiword 216.7

In 1994 Enhanced IDE (EIDE) was developed by Western Digital to:- increase the maximum data throughput to up to 16.7 MBps.- increase the 528MB size limit to 8.4GB.- support two controllers instead of one, allowing a maximum of four disks instead of two.

Seagate and Quantum developed similar technologies which were promoted as FASTATA and FASTATA-2. Eventually, the features of the these unofficial standards were combined in the official standard ATA-2. Besides the improvements listed above, ATA-2 offers support for:- Logical Block Addressing (LBA) and block transfer- PIO modes 3 and 4- Multiword DMA modes 1 and 2

Several CD-ROM drive manufacturers, including Western Digital, worked together to develop a specification that would allow CD-ROM drives and tape drives to be connected to the same interface and cable as hard disk drives. The Small Form Factor (SFF) committee initially published it as the AT Attachment Packet Interface (ATAPI) specification. ATAPI eventually became an extension to ATA in ATA/ATAPI-4.

Several other additions were made to the ATA standard, such as ATA-3, which introduced some reliability features and allowed password protection for devices. The first major new version of ATA was ATA/ATAPI-4, which combined ATA with ATAPI and introduced Ultra DMA. Again there are several modes, all multiword, of Ultra DMA. The table below lists the Ultra DMA modes along with their corresponding maximum transfer rates. ATA/ATAPI 4 supports Ultra DMA mode 0, 1, and 2. Ultra DMA mode 2 is also known as Ultra DMA/33, Ultra-ATA, and ATA-33.

Ultra DMA ModeTransfer Rate (MBps)

Mode 0

16.7

Mode 125

Mode 233.3

Mode 344.4

Mode 466.7

Mode 5100

Mode 6133

ATA/ATAPI-5, added support for Ultra DMA mode 3 and 4. Ultra DMA mode 4 is also known as Ultra DMA/66. ATA/ATAPI-6 introduced Ultra DMA mode 5, supporting data transfer rates up to 100MBps.

Intel and a group of other companies have developed a serial version as an alternative to the parallel ATA interface and was published as Serial ATA (SATA). The SATA specification was handed over to T13 to include it in ATA/ATAPI-7 (volume 3) and is now called SATA-1. ATA/ATAPI-7 includes UltraDMA mode 6 already known as Ultra DMA 133, some new commands for use by digital video recorders, and T13's version of Serial ATA, SATA-1. SATA can transfer data up to 150MBps (and will likely advance to 300 MB and 600 MB per second in the near future), making it, in theory, faster than parallel ATA (now also referred to as PATA) using UltraDMA mode 6 running at 133MBps. These transfer rates are so called burst rates, the average rates are much lower making the difference between PATA and SATA very small. The currently available SATA hard disk are mostly not native SATA drives, instead the disks include a chip that functions as a parallel-to-serial bridge. This bridge limits the transfer rates which would be 1.5Gbps according to the first version of SATA.

The Serial ATA final 1.0a specification was released on Feb 4, 2003. Intel continues to work on SATA and joined forces with a the Serial Attached SCSI (SAS) subdivision of T10. They are currently working on an extension to the SATA 1.0a specification, called SATA II, which focuses on support for multiple devices per SATA bus, RAID, and more.

Installing an 'IDE' deviceA standard PC is usually equipped with two IDE controllers ("ATA interfaces" The picture below on the left, shows a regular flat ribbon 40-pins/wires IDE cable with 3 connectors, also referred to as an IDE-33 cable. The devices connect to the two connector closest together, the connector on the far end connects to the mainboard's IDE connector. One side of the cable has a red edge to mark the side that connects to pin 1 on the mainboard's connector and pin 1 on the device.

The picture on the right shows a flat ribbon IDE-66/100 cable with 80 wires. The extra 40 strands in an 80-wire cable act as insulators between the 40 signaling strands to prevent crosstalk. This type of cable usually has one blue connector, this connector connects to one of the mainboard's IDE connectors. The black connector connect to the master device and the gray/white connector to the slave. This type of cable was optional for ATA/ATAPI-4 compliant devices and is mandatory in ATA/ATAPI-5 to be able to support the maximum transfer rates. If you have an ATA/66, 100 or 133 drive without the 80-wire cable, the drive will only run at 33MB/sec. An alternative to the flat ribbon cable has been introduced a couple of years ago. The main advantage is better airflow inside the computer's case, hence a 'cooler' system.

SATA supports a single device per SATA cable. A SATA cable can be longer than a parallel ATA cable (max. 1.5 feet), about 3 feet. Serial ATA has a thinner cable and a smaller connection that is keyed so they cannot be connected incorrectly, unlike some parallel ATA cables. The following pictures show the new Serial ATA 7-wires cable and its connectors.

RAID

RAID stand for Redundant Array of Inexpensive (or Independent) Disks, and is commonly used on servers in corporate environments. It allows multiple hard disks to be combined. The three most common, and important for the Network+ exam, are described next.

RAID 1 refers to Disk Mirroring/Duplexing. This configuration requires two, in some cases identical, hard disks. When the OS writes data to the hard disk, the same data is also written to the mirrored disk. This may slow down write performance, but increases read performance since data can be read form both disks at the same time. It's called duplexing when each disk has its own hard disk controller, providing an extra level of redundancy. When a disk fails the other disk can continue to operate, in some configurations this process occurs entirely automatically. In Window NT and higher, when the main disk fails, you'll need to manually configure the system to use the mirrored disk.

RAID 5 is more advanced and requires at least 3 hard disks. RAID 5 is also known as a stripe set with parity. When data is written to the RAID 5 set, it is distributed over several disks, and parity information about data blocks on one disk are stored on the other disks. In case of a disk failure, the parity information can be used to reconstruct the data which was on the missing disk. Because data is spread out over several disks, RAID 5 offers better read performance than single or mirrored disks. But because every write requires the parity calculation, write performance can be slower, especially when RAID 5 is implemented in software. If two disks in a RAID 5 set fail, you will need to replace the disks and restore the information from backup.

Fault tolerance RAID configurations implemented in hardware usually offer hot-swapable drives. This means you can pull out and replace a drive while the system is running, and it will perform the reconstruction of the data automatically.

Another type is RAID 0, also known as a stripe set. It requires at least 2 hard disks, but does not offer fault tolerance, it's merely a method of combining hard disks to allow for larger volumes. When a file is written to a RAID 0 stripe set with 2 disks, the first block is written to the first disk, the second block to the second disk, and the third data block is written on the first disk, and so on. If one of the hard disks in the stripe set fails, the entire stripe set is lost and needs to be rebuild and restored from backup.

6) LASER PRINTERSCharacteristics of laser printersLaser printers use an electro-photographic process to print one page at a time using a plastic powder (toner) instead of ink. Laser printers are nonimpact devices, hence they make less noise compared to dot matrix printers and generally faster than dot matrix or inkjet printers.

Print resolution is measured in DPI (dots per inch) which ranges from 300 to 1200 DPI. Many modern laser printers are able to use a technology called Resolution Enhancement Technology to increase the maximum effective resolution to even more. Be aware that the higher the resolution or RET settings the higher the amount of physical RAM the printer will need.

Laser printer output is controlled by page description languages (PDLs: the Printer Control Language or PostScript.)

How does a laser printer work? 1. Photosensitive drum is cleaned (by an Erase lamp, and scraper) 2. Photosensitive drum is negatively charged (by the Primary Corona) 3. Image is written on the drum by positively charging the places where the toner should be placed (by Laser) 4. Toner with a negative charge is placed on the drum. 5. Toner is transferred to the paper. (The Transfer Corona positively charged the paper.) 6. The toner is melted onto the paper by the fuser (a heat and a pressure roll.) Font CartridgesFont Cartridges provide fonts on ROM boards and can be placed in many laser printers. Fonts can often also be 'downloaded' to RAM.

Troubleshooting Laser Printers Symptom/Problem Possible cause(s) Possible solution(s) Print results are too light, white/light columns. Toner is low.Defective transfer corona. Replace toner cartridge / fill toner reservoir. Ghosting Drum is not fully discharged, erase lamp not functioning, previous image used too much toner. 1. Print couple of black pages2. Replace cartridge3. Call a trained service technician to replace Erase lamp. Memory overflow error Image size too large. 1. Reduce the print resolution and/or Resolution enhancements technology.2. Add more RAM to the printer. Prints totally black pages. Damaged primary corona Call a trained service technician to replace the primary corona. Pages are dirty with toner. Dirty fuser.Leaking cartridge.Paper Transport component is dirty.1. Print a couple of blank pages.2. Clean/vacuum the printer. Multiple pages are pulled in at a time. Wrong paper type.Defective Paper transport. Try thicker paper and make sure it is clean/dry. Miscellaneous notes: - Do not connect a laser printer to an UPS, laser printers consume a lot of power so your UPS will be empty in no time.- Always be careful when servicing a laser printer, you don't want your tie to get stuck in the fuser pulling you in... it's hot! ;)- Some laser printer can be expanded with a duplexing paper tray that enables printing on both sides of pages. INKJET PRINTERS

Characteristics of inkjet printersInkjet printers come in many different types and sizes they are mostly used as desktop printers and most of them are able to print in color.Inkjet printers are generally cheaper to buy than laser printers, however they are more expensive to maintain. Cartridges need to be changed more frequently and special paper may be needed to produce a good quality image. Inkjet printers are non-impact devices hence are quieter than dot matrix printers.

Most inkjet printers work by spraying small ink onto paper through tiny nozzles. Spraying is initiated by heating the ink to create a bubble until the pressure forces it to burst and hit the paper. Then the nozzle gate is closed again and the process repeats. This occurs a thousands of times per second.

Most inkjet printers come with advanced tools that allow you to clean the nozzles (takes a lot of ink) and align new ink cartridges. Inkjet printers commonly provide a print resolution ranging from 300 to 1200 DPI.

Troubleshooting Inkjet Printers Symptom/Problem Possible cause(s) Possible solution(s) Print results are too light. Ink level in cartridge too low. Replace ink cartridge. Print results are smudged. Paper not fit for inkjet ink. Try using other paper. Printer does not print. 1. Printer is offline. 2. Printer is out of paper.1. Turn printer online.2. Add paper.Paper gets stuck or does not advance. Damaged paper feed mechanism or just wrong type of paper. 1. Try using other paper.DOT MATRIX PRINTERS

Characteristics of dot matrix printersAlthough the inkjet printer replaced most dot matrix printers many companies still own a couple of them to print (mostly characters) on continues forms. Dot matrix printers are impact printers, they create images by striking an inked ribbon onto an paper using pins and make more noise than laser and inkjet printers. The pins are placed on the print head mostly in an array of 9 or 24 pins. Needless to say, the resolution is measured in dots per inch, the higher the amount of pins the higher the resolution. Paper is mostly feeded using tractor wheels although some dot matrix printers use a plain sheet feeder.

Print speeds, specified in characters per second (cps), varies from about 50 to over 500cps.

Troubleshooting Dot Matrix Printers Symptom/Problem Possible cause(s) Possible solution(s) Print results are too light. Ribbon cartridge is out of ink. (dry) Replace ink ribbon. Error-led flashes. Printer overload. Leave it for a while and remove all print jobs. Try printing in smaller portions. Printer does not print.

1. Printer is offline.2. Printer is out of paper.3. Printer is not connected.

1. Turn printer online.2. Add paper.3. Check cable connections. Paper does not advance. Paper is not properly placed or paper-feed mechanism is broken. Make sure the paper is aligned and the tractor wheels are in place. Characters are incomplete. Pins are stuck or broken.

Replace the print head PRINTER CONNECTIONS

Parallel (LPT, IEEE 1284)This is the most common used connection today.-EPP / ECPIn the CMOS you are able to configure a parallel port to use EPP or ECP. Enhanced Parallel Port and Extended Parallel Port are both bi-directional standards, operate in 8-bit, and allow data transfer speed of approximately 2 MB/s. Some of the main differences are that ECP supports Direct Memory Access (DMA) and data compression, which enables higher transfer rates. SerialSome older printers can be connected to a Serial port (COM port). USBMany modern printers (especially desktop printers) use an USB connection. USB printers often can be connected and installed without having to reboot. InfraredOften used in combination with portable computers. NetworkMost printers in offices are network printers. These are attached to a Print Server (or a module simulating one) and are available to anyone with appropriate permissions in the network. Current Printer related exam objectives for the 2002 A+ Core exam: 4.4 Identify the purpose of CMOS (Complementary Metal-Oxide Semiconductor), what it contains and how to change its basic parameters.Example Basic CMOS Settings:- Printer parallel portUni., bi-directional, disable/enable, ECP, EPP

Domain 5.0 PrintersThis domain requires knowledge of basic types of printers, basic concepts, and printer components, how they work, how they print onto a page, paper path, care and service techniques, and common problems.

5.1 Identify basic concepts, printer operations and printer components.Content may include the following:Paper feeder mechanismsTypes of Printers- Laser- Inkjet- Dot MatrixTypes of printer connections and configurations- Parallel- Network- USB- Infrared- Serial

5.2 Identify care and service techniques and common problems with primary printer types.Content may include the following:- Feed and output- Errors (printed or displayed)- Paper jam- Print quality- Safety precautions- Preventive maintenance

7) NAME CPU TYPES # of PINS*

Socket 1: 486 SX & DX 169

Socket 2: 486 SX, DX, & DX2 238

Socket 3: 486 SX, DX, DX2, DX4, 586, Pentium Overdrive 237

Socket 4: Pentium 60 & 66 273

Socket 5: Pentium 75, 90, 100, 120, 133 320

Socket 6: 486 DX4 (75, 100, 133) 235

Socket 7: Intel Pentium & Pentium MMX P75 thru P233, AMD K5/K6, Cyrix 686/686MX 321 Supersocket 7: AMD K6-2, AMD K6-3, Cyrix 686-MII, Intel Pentium up to P233MMX, AMD up to K6/2-550, Cyrix MII up to 433 321

Socket 8: Pentium Pro, Pentium Pro OverDrive, Pentium II OverDrive 387

Socket 370: Intel Celeron, Pentium III 370

Slot I: Intel Pentium II, Pentium III, Intel Celeron 242

Slot A: AMD K7, Athlon 242

Slot II: Intel Pentium II Xeon, Pentium III Xeon 330

Socket A: AMD Athlon, AMD Duron 462

Socket 423: Early Pentium 4 423

Socket 478: Newer Pentium 4 478

* You do not need to memorize the amount of pins for the exam.

CPU TYPES BUS WIDTH

8088 8-bit

8086 16-bit

80286,80386SX 16-bit

80386DX 32-bit

80486 32-bit

Pentium I, II, III IV 64-bit

CPU TYPES BUS SPEEDS in MHz

Pentium 50, 60, 66

Pentium Pro 60, 66

Pentium MMX (133 - 300 MHz) 66

Celeron (266 - 766 MHz) 66

Celeron (800 - 1.4 GHz) 100

Celeron (1.7 - 2 GHz) 400

Pentium II (266 - 333 MHz) 66

Pentium II (350 - 450 MHz) 100

Pentium III (450 - 1.1 GHz) 100

Pentium III (533 - 1.4 GHz) 133

Pentium IV (1.3 - 2.6 GHz) 400

Pentium IV (2.26 - 2.8 GHz) 533

8) MONITORSCRTThe CRT (Cathode-ray tube) is the most common type of monitor in use. Most CRT monitors today have three electron guns in the back, one for red, one for green and one for blue. These guns shoot electric beams on the inside of the display screen on a phosphor coating to light up RGB dots that produce a pattern of pixels. In other words, a beam of light moves across the back of the screen and produces and image on the screen.

CRT monitors are high-power devices and should be handled with care, you should never open the cover unless you are a trained technician and you know what you are doing. If you are a technician and you open a CRT, make sure to remove your anti-static wrist strap or the capacitor could use you as a human conductor of electricity. Some CRTs can hold their charge for days.

CRTs connect to you computer with the DB 15-pin male connector on the cable, and the DB 15-pin connector on the video adapter.

LCDLCD or Liquid Crystal Display screens are usually found on laptops, but are becoming popular as flat panel monitors. LCD technology requires two sheets of a polarizing material to have a liquid crystal solution between them. As electrical currents pass through the liquid, the crystals align which blocks light from passing through.

There are two types of LCD screens. Passive matrix is less expensive and doesnt provide sharp graphical images. The second type, TFT (Thin Film Transistor) is also known as Active Matrix and is more expensive, but produces very sharp images comparable to the images on a CRT.

An LCD screen can either connect to your computer through standard DB 15-pin connectors, or through USB. LCDs also have 12V AC external power supplies.

Touch ScreenTouch Screen monitors look like any other monitor but they have a transparent panel around them that is sensitive to touch. With a touch screen monitor you can just point to an area on the screen, thus eliminating the need for a mouse. In most instances, touch screen monitors are really not that useful, as it is hard to touch very small areas, however, there are businesses that use them successfully.

VIDEO ADAPTERSVideo adapters have been made for all of the common I/O buses, but the ones CompTIA wants you to know about for the A+ exams, are the PCI and AGP buses.

PCI or Peripheral Component Interconnect video adapters were introduced in 1993 and are generally only 32-bits wide. PCI video cards are good, but not good enough for higher end graphics and 3D graphics.

AGP or Accelerated Graphics Port video adapters are much faster than PCI cards, and can handle higher end graphics and 3D graphics. The AGP bus was created specifically for video, and it provides a direct connection between the AGP video card and the CPU. AGP video adapters are available in both 32-bit and 64-bit sizes. AGP comes in 2x, 4x and 8x modes. Each of these modes has a different voltage. The 2x/4x/8x is the data transfer speed. An 8x motherboard can take a 4x card, as long as the voltages match. Motherboards can handle the different voltages; so the manufacturer determines which voltages will be work. It is best to ignore the 2x, 4x and 8x when shopping for a video card, and pay more attention to the voltages that your Motherboard can handle.

The voltages for the AGP modes are as follows:

1X/2X = AGP1.0 Spec = 3.3V2X/4X = AGP2.0 Spec = 1.5V4X/8X = AGP3.0 Spec = 0.8V

Screen ResolutionScreen resolution is the number of horizontal pixels multiplied by the number of vertical pixels on your screen. For instance if your screen resolution is set at 1024x768, it means you have 1024 horizontal pixels and 768 vertical pixels. You can change your screen resolution through the display properties dialogue box, by right-clicking on your desktop and choosing Properties from the short-cut menu.

PixelsPixels are made up of a triad of phosphors. A triad is made up of one red, one green, and one blue phosphor. Each trial of phosphors equals one pixel.

Refresh RateThe refresh rate is the speed at which the electron guns sweep across your screen. Basically, electron guns begin sweeping horizontally across your screen from the upper left corner energizing the phosphors and pixels and finishes in the lower right corner. The horizontal refresh rate is defined as the rate at which the electron gun sweeps across the screen. The vertical refresh rate is the speed at which an entire screen is swept and the electron guns return to the upper left corner. Refresh rates are measured in Hertz (Hz).

Dot PitchThe dot pitch of the screen is the distance (measured in millimeters) between two same colored phosphorus dots diagonally.

InterlacingInterlacing is generally used in lower-end monitors. In monitors with interlacing, the monitor refreshes alternate lines of pixels and thus it takes two sweeps to produce one image.

Color DepthColor depth is basically the number of distinct colors that can be represented through your video adapter, and refers to the number of bits used for each pixel. For example, if you have a 32-bit video adapter, your video adapter has a color depth of 32-bits.

Video Mode Resolution and Color Depth

CGA320 x 200 with 4 colors640 x 200 with 2 colors

EGA640 x 350 with 16 colors from a palette of 64 colors (text mode) 640 x 200 with 2 colors (graphics mode)

VGA640 x 480

SVGA640 x 480, 800 x 600, 1024x 768 and higher with X colors from a palette of 16.7 million color.(X depends on the amount of video ram, ranges from 256 - 16.7 million)

To determine whether or not your memory card can handle a particular resolution use the following calculation: horizontal resolution X vertical resolution X color depth, divided by 8,388,608.

VIDEO BIOS SETTINGSThere are several video BIOS settings, however most are not in use today.

VideoThis video BIOS setting used to tell your BIOS what type of video card you had in your system, and how to talk to it. The default setting was generally EGA/VGA. This setting is of no use today, and is ignored by your system regardless of how you set it.

Init Display FirstThe Init Display First BIOS setting is used for systems with more than one monitor. If you have more than one monitor on your system, it lets you decide whether you want the AGP or the PCI monitor to start up at boot. This setting is also used by Windows 9x and up to set the primary display monitor.

Assign IRQ for VGAMost video cards dont require an IRQ, and thus in most cases this setting is useless. This setting lets you decide whether or not you need an IRQ for your video card. You generally dont have to worry about this setting if you have a video card that needs an IRQ youll know because your system will freeze up.

VGA Pallet SnoopVGA Pallet Snoop is an old setting that is no longer in use. It used to open a PCI video cards pallet so that other devices could read or change the palette.

Video Shadowing EnabledThe Video Shadowing Enabled setting is outdated and no longer in use. This setting used to let you shadow video ROM. Today this setting is ignored because most video cards are capable of performing video shadowing themselves.

VIDEO RAMMany different types of RAM are used or have been used on video adapters. Some even use plain EDO RAM, but most video adapters come with special video RAM used to optimize video performance. More video RAM allows for more colors and a higher resolution to be displayed.

Video RAM constantly updates in order to show ever change that takes place on your screen. CompTIA wants you to know about the VRAM, WRAM, and SGRAM types of Video RAM for the A+ certification exams.

VRAMVRAM or Video RAM is dual ported (it can be read to and written from at the same time). Although VRAM is fast, it is not as fast as WRAM.

WRAMWRAM or Windows Accelerator Card RAM is faster than VRAM, and thus produces better video than VRAM. WRAM is also dual ported, meaning it can be both read from and written to at the same time.

SGRAMSGRAM or Synchronous Graphic RAM synchronizes with the CPU bus. SGRAM uses masked writes and blocked writes in order to increase bandwidth for intensive graphics. SGRAM is not dual ported, and cannot be read to and written from at the same time, although it can open two memory pages at once.

DOMAIN 1. Installation, Configuration, and Upgrading1.1 Identify the names, purpose, and characteristics, of system modules. Recognize these modules by sight or definition.Examples of concepts and modules are:- Display devices1.2 Identify basic procedures for adding and removing field-replaceable modules for desktop systems. Given a replacement scenario, choose the appropriate sequences.- Display device- Input devices-- Touch screen- Adapters-- Video card1.8 Identify proper procedures for installing and configuring common peripheral devices. Choose the appropriate installation or configuration sequences in given scenarios.- Monitors1.9 Identify procedures to optimize PC operations in specific situations. Predict the effects of specific procedures under given scenarios.- Specialized video cards

DOMAIN 2. Diagnosing and Troubleshooting

2.1 Recognize common problems associated with each module and their symptoms, and identify steps to isolate and troubleshoot the problems. Given a problem situation, interpret the symptoms and infer the most likely cause.- Display device- Input devices-- Touch screen- Adapters-- Video card

DOMAIN 3. PC Preventive Maintenance, Safety, and Environmental Issues

3.1 Identify the various types of preventive maintenance measures, products and procedures and when and how to use them.- Cleaning monitors3.2 Identify various safety measures and procedures, and when/how to use them.Content may include the following: - Potential hazards and proper safety procedures relating to:-- CRTs3.3 Identify environmental protection measures and procedures, and when/how to use them.Content may include the following:- CRTs

DOMAIN 4. Motherboard/Processors/Memory

4.2 Identify the types of RAM (Random Access Memory), form factors, and operational characteristics. Determine banking and speed requirements under given scenarios.- Types:-- VRAM (Video RAM)4.3 Identify the most popular types of motherboards, their components, and their architecture (bus structures). Content may include the following:- AGP-- 2X-- 4X-- 8X (Pro)

9) BIOSBIOS is short for Basic Input/Output System. This small program is used to startup the computer and communicate with hardware before an operating system is loaded.BIOS is stored in ROM chips on the mainboard. Some chips contain programs to support basic hardware such as parallel and serial ports, keyboard and the speaker. Another ROM chip, called the CMOS (complementary metal-oxide semiconductor) chip stores information that is subject to change such as time/date, power saving settings, and video adapter, hard drives and other device settings.BIOS settings are applied at every startup. Modern PCs copy the BIOS information to RAM for faster performance, this process is called shadowing.Here is a picture of a common BIOS CHIP:click here

BIOS UpgradesMost modern BIOSs are stored on flash memory, this enables you to upgrade the BIOS software when needed, in some cases this is necessary to support new hardware technologies/devices.Upgrading the BIOS is called flashing, before you do make sure you write down all settings and during the process pray the power won't be interrupted. The BIOS version ID is displayed during startup.Some mainboards allow replacing the BIOS ROM, although this is not done often.

POSTDuring startup the BIOS also invokes The POST (Power On Self Test), also stored in ROM, a program that runs multiple self-diagnostic routines. When the computer does not pass the POST it will display an error code or message, or generate a beep code through the speaker when display is not functioning. Failing the POST does not always mean the computer will not be able to boot, required devices that need to pass the POST are CPU, RAM, display adapter and boot device, but if the floppy drive is missing the computer can still be able to continue the boot process. The meaning of the beep codes vary depending of the manufacturer mostly they indicate memory, CPU, display and keyboard problems. Most BIOSs beep once to check if the speaker is working or to confirm that the post has passed successfully.For the exact meaning of beep codes for AMI BIOSs INCLUDEPICTURE \d "/images/awardbios.jpg"

CMOS settings can be changed in the CMOS Setup, which can mostly be entered by pressing the DEL or F2 key during startup (depends on manufacturer, other key or key combinations might apply). Some of the most common CMOS settings are described later in this TechNote.Most mainboards have a "CMOS restore to factory defaults"- jumper which allows you to return to the default CMOS settings configured by the manufacturer. This is useful when you cannot access the CMOS Setup because of incorrect CMOS settings or lost CMOS passwords. Make sure the power is completely off when you shorten the jumper.

CMOS BatteryThe information contained in the CMOS chip is maintained by a battery.If the battery runs low, the CMOS content will be lost and POST will display a "CMOS invalid" or "CMOS checksum invalid" message. The first symptom for a battery running low is time slowing down and eventually complete loss of date and time. In some cases you might get a boot device error because a boot device such as floppy disk or hard drive can not be located. Almost always the CMOS battery can be replaced very easily.Here is a picture of a common CMOS battery: and for Phoenix and Award click here.

Although most BIOS manufacturers started using error text messages, some use numeric POST error codes. Some of them are listed below POST error code Probable Cause 1xx Mainboard related errors 200-299 Memory related errors. 3xx Keyboard related errors 151 Real-time clock failure 161 BAD CMOS memory 6xx Floppy Disk related errors 1700-x Hard drive controller 31xx Network Adapter related errors Click here for a complete list of numeric error codes by IBM. COMMON CMOS SETTINGS

Printer parallel portUni., bi-directional, disable/enable, ECP, EPPIn the CMOS you are able to configure a parallel port to use EPP or ECP. Enhanced Parallel Port and Extended Capabilities Port are both bi-directional standards, operate in 8-bit, and allow data transfer speed of approximately 2 MB/s. Some of the main differences are that ECP supports Direct Memory Access (DMA) and data compression, which enables higher transfer rates.It is also possible to completely disable the parallel port in the BIOS. Most BIOSs allows you to set the DMA channel, when the port mode is set to ECP.

COM/serial portMost personal computers have 2 serial ports. In the BIOS you can assign COM1/COM2/COM3/COM4 to serial port 1 or 2.Most BIOSs also allow you to set the I/O and IRQ but this is mostly done automatically.

Floppy drivesThe floppy drive(s) can be enabled/disabled in the BIOS (e.g. set to Not Installed). The BIOS also allows you to choose the capacity of the media.- 360 KB 5.25 inch- 1.2 MB 5.25 inch- 720 KB 3.5 inch- 1.44 MB 3.5 inch- 2.88 MB 3.5 inchSome BIOSs also allows you to swap A: and B: and disable seeking a floppy disk for a boot sector during startup.

Hard drivesMost modern BIOSs allow automatically detection of disk parameters. These are some of the primary CMOS settings that apply to hard drives (and CD/DVD-ROM drives, etc.), the settings can be individually configured for the primary master and slave device and the secondary master and slave device.

TypeCommon disk types are:- User, User-defined CHS values- Auto, automatically detects hard disks parameters at every startup.- 1-46, predefined combinations of CHS values.- CDROM, used for atapi CD-ROM drives- ARMD, used for atapi ZIP and LS 120 drives.- DVDROM

SizeDetermines the capacity of the drive.

CHS values- number of Cylinders- number of Heads- number of Sectors

LBA (Large Block Addressing), technologie to overcome the 528 MB limit.

Another common CMOS setting related to hard drives is Boot Sector Virus protection Enabled/Disabled, enabling this will make the BIOS issue a warning message/beep if a write to the boot sector or partition table of a hard disk is attempted.

MemoryToday's motherboards provide too many BIOS settings regarding to memory to discuss here and most are beyond the scope of the exam.CompTIA does mention parity, non-parity in the exam objectives;Parity adds an extra bit (odd or even) to the 8-bit data-string to ensure data integrity in memory modules. Its successor, ECC, provides even better ways to ensure the data integrity by adding information about individual bits.

Boot sequenceThis setting is used to determine in which order devices (e.g. CD, floppy or hard disks) the computer should look for a boot sector.

Date/TimeThe Date and Time is set in the BIOS, stored in CMOS, maintained by CMOS battery.

PasswordsIn most cases a user (startup) password and a supervisor (setup) password can be set in the CMOS. When a Setup password is required the computer will prompt for it when you try to access the BIOS setup. When a Startup password is configured the computer will prompt for it at every startup.The CMOS password can be reset by shortening the "CMOS restore to factory defaults jumper" or by temporarily removing the CMOS battery.

Plug & Play BIOSToday's BIOSs are PnP-aware. This means they are able to automatically assign resources such as IRQ and DMA to Plug and Play devices.Information about these PnP devices is stored in a separate area of non-volatile CMOS memory, called the ESCD (Extended System Configuration Database). The PnP BIOS and the operating system can both access this area so they can communicate with each other about resource settings assigned to PnP devices and also to non-plug and play devices. For example, when a fixed IRQ is manually assigned to a particular device using Device Manager, Windows will write this information to the ESCD on shutdown preventing the BIOS from assigning the same IRQ to a PnP device at startup.You can also reserve IRQ's for non-plug and play devices in the CMOS setup, this will prevent the BIOS from assigning these reserved resources to PnP devices, a common example is a legacy sound card that needs IRQ 5.

Power ManagementModern mainboards provide ACPI (Advanced Configuration and Power Management Interface) settings such as wake-up, power button function and standby/suspend timers, these are also configured in the CMOS Setup.

Current CMOS related exam objectives for the 2002 A+ Core exam.1.1 Identify basic terms, concepts, and functions of system modules, including how each module should work during normal operation and during the boot process.Examples of concepts and modules are:- BIOS- CMOS

1.8 Identify hardware methods of upgrading system performance, procedures for replacing basic subsystem components, unique components and when to use them.Content may include the following: - Upgrading BIOS- When to upgrade BIOS

2.1 Identify common symptoms and problems associated with each module and how to troubleshoot and isolate the problems.Content may include the following:- CMOS- BIOS

4.4 Identify the purpose of CMOS (Complementary Metal-Oxide Semiconductor), what it contains and how to change its basic parameters.Example Basic CMOS Settings:- Printer parallel portUni., bi-directional, disable/enable, ECP, EPP- COM/serial portmemory address, interrupt request, disable- Floppy driveenable/disable drive or boot, speed, density- Hard drivesize and drive type- Memoryparity, non-parity- Boot sequence- Date/Time- Passwords- Plug & Play BIOS

10) ModemsModems are used to for low-speed long-distance connections over telephone lines. Modems convert parallel digital data to serial analog data and vice versa.

There are two main types of modems:

- InternalExpansion cards (e.g. ISA, PCI) or 'On-board' (integrated in mainboard)

- External Modems that connect to the serial RS-232 or USB port and often have their own power supply.PCMCIA/PCcard modems can also be considered external modems but these are becoming less common since most modern portables are equipped with an integrated modem.

Installing and Connecting Modems

Install an internal modem by inserting the expansion card in to an ISA or PCI expansion bus, and if the OS or the modem is not PnP assign an IRQ and I/O address.

External modems connect to an RS-232 or USB port on the computer. Most modern PCs are equipped with one or two 9-pin serial ports (DB-9), also commonly known as COM ports, older PCs often also have a 25-pin serial port (DB-25)

The following picture is an example of a serial cable used to connect an external modem to a COM port on the PC:

Modems and Serial Port related exam objectives for the 2002 A+ Core exam.

1.1 Identify basic terms, concepts, and functions of system modules, including how each module should work during normal operation and during the boot process.Examples of concepts and modules are:- Modem- Ports

1.3 Identify available IRQs, DMAs, and I/O addresses and procedures for device installation and configuration.Content may include the following:- Standard IRQ settings- Modems

1.4 Identify common peripheral ports, associated cabling and their connectors.Content may include the following:- Cable types- Pin connectionsExamples of types of connectors:- DB-9- DB-25- RJ-11

1.7 Identify proper procedures for installing and configuring peripheral devices.Content may include the following: - Modem

2.1 Identify common symptoms and problems associated with each module and how to troubleshoot and isolate the problems.Content may include the following:- Modems

11) PORTABLES

Portables have earned their popularity over the years. At one time, not many people had portables, then some had portables and desktop PCs, and now these days there are lots of people who only own portable computers. CompTIA wants you to know about some of the components of the portable computer.

RAMThe types of RAM used by portable computers are called SO-DIMs. SO-DIMs are available in two sizes: 72-pin or 144-pin. The 72-pin SO DIMMs are 32-bits wide, and the 144-pin SO DIMMs are 64-bits wide.

In order to replace RAM on a portable, follow the manufacturers instructions as per opening the case, and then insert the RAM modules into the slots firmly.

Hard DrivesPortable computers used to have 3.25 hard drives, but these days the popular size is 2.5 for a hard drive. Hard drives in portable computers have the same features and configurations as ATA drives.

In order to replace a hard drive inside a portable, follow the manufacturers instructions as per opening the case, and then attached the ribbon and power cables firmly.

CPUsCPUs in portables are of course specially made by the manufacturer. Of course, you can upgrade and replace the CPU on your portable, just like you can on a PC.

In order to replace the CPU on a portable, follow the manufacturers instructions as per opening the case, and then hold the CPU over the socket and gently set it down into place, then press firmly.

Replacing Other ComponentsIn order to replace other components such as floppy drives, CD-ROM drives and CD-RW drives, please follow the instructions from your manufacturer. Although CompTIA includes these in their objectives, you will never be tested on it, as different manufacturers have different methods for replacing components on a portable, including hard drives, CPUs and RAM. I was reluctant to put any info as to replacing these units on a portable in here because there is so much room for error with so many different manufacturers that make laptops that open up different ways and as I said CompTIA will not test you on replacing units on a portable either because they know its too proprietary.

PC CardsNow that weve talked a little bit about the basic components of a portable computer, lets look at PC Cards. PC cards are credit-card sized cards that are hot-swappable. Almost any component or device can be in the form of a PC card including hard drives, modems, network cards, and the list goes on.

PC cards were created by the PCMCIA (Personal Computer Memory Card International Association). The PCMCIA has set standards for PC cards, and while these standards are not set in stone, most manufacturers follow them:

Type I cards are 3.3mm thick and are generally for memory.Type II cards are 5 mm thick and are generally for modems or NICsType III cards are 10.5mm thick and are generally for hard drives

Please note that all PC cards have 68-pins and run at 5.5V.

Two levels of software drives are required to support PC Cards: Socket Services and Card Services. Socket Services drivers detect the component. Card Services drivers recognize the function of the card, and provide specialized drivers to allow the card

to perform that function.

Card BusThere is a new type of PC card on the market Card Bus cards. Card bus slots use synchronous burst transfer just like PCI slots. Card Bus cards can provide up to 8 functions; whereas, PCMCIA cards can only provide two functions.

All Card bus cards run at 3.3V. and have 68-pins.

PC cards can plug into Card Bus slots for backwards compatibility, but Card Bus cards wont fit into PC card slots.

Power ManagementAll components of a portable obviously require power. Therefore CompTIA feels that it is necessary for you to know about Power Management for the A+ exams.

System Management ModeSystem Management Mode allows the CPU to slow down its cycle, and in some cases top its cycle without having to register information.

APM/ACPIIntel introduced APM (Advanced Power Management) in 1992 and APCI (Advanced Configuration and Power Interface) in 1996.

Both APM and ACPI require four features in order for them to function:

1. A System Management Mode CPU (almost all CPUs made today are)2. An APM Compliant BIOS3. All devices will accept being shut off (most energy star compliant devices will)4. The operating system has to know how to shut the devices off

There are 5 Power levels defined by APM/ACPI. Those power levels are: Full On, APM Enabled, APM Standby, APM Suspend, and Off.

For Full On, there is no power management and all components run at full power. APM Enabled causes the CPU and RAM to run at full power, power management to be enabled, and unused devices to be possibly shut off (they may or may not be shut down). APM Suspend causes everything in the PC to be shut down or at its lowest power consumption setting. APM Standby causes the CPU and all peripherals to be shut down. The Off setting causes your computer and all of its devices to be powered down.

You can configure APM/ACPI in the CMOS or through Windows. If you configure it in Windows, it will override any CMOS settings.

BatteriesOne of the disadvantages of portables is their dependency on batteries. In order to be a good technician, and for the A+ exams, it is essential that you know about batteries.

Nickel Cadium (Ni-Cd)Nickel Cadium batteries were the first batteries for portable computers. They must have a steady voltage and tend to lose their capability to recharge if recharged repeatedly without being totally discharged.

Nickel Metal Hydride (Ni-MH)Nickel Metal Hydride batteries have been around for a while, and are still quite common. These batteries can tolerate overcharging, and last longer between chargings.

Lithium Ion (Li-Ion)Lithium Ion batteries are the most commonly used batteries for portables today. They are extremely powerful, and have a long lasting charge. Be careful with Lithium Ion batteries though theyll explode if they are overcharged.

Smart BatteriesThere are batteries out there called Smart Batteries that tell the computer when they need to be charged or replaced.

Fuel Cell BatteriesFuel Cell batteries are the newest kind of portable batteries, and they provide clean-burning energy. Fuel cells produce energy by removing electrons from hydrogen fuel and transporting them to oxygen, via electrodes and an electrical circuit.

Docking StationsDocking Stations give portables access to the same things that normal PCs use: full sized monitors, mice, network connections and many others. Docking stations make it very convenient for a company to have portable computers only for their workers.

Hardware ProfilesA talk about portables would not be complete if hardware profiles were not mentioned. A hardware profile is a list of devices that Windows automatically enables or disables in the Device Manager. You can create a hardware profile for any system but hardware profiles were originally created for portables.

Portables related exam objectives for the 2003 A+ Core exam.1.3 Identify basic procedures for adding and removing field- replaceable modules for portable systems. Given a replacement scenario, choose the appropriate sequences.Portable components:- Storage devices- FDD- HDD- CD/CDRW- DVD/DVDRW- Removable storage- Power sources- AC adapter- DC adapter- Battery- Memory- Input devices- Keyboard- Mouse/pointer devices- Touch screen- PCMCIA/Mini PCI Adapters- Network Interface Card (NIC)- Modem- SCSI- IEEE 1394/Firewire- USB- Storage (memory and hard drive)- Docking station/port replicators- LCD panel- Wireless- Adapter/controller- Antennae

1.8 Identify proper procedures for installing and configuring common peripheral devices. Choose the appropriate installation or configuration sequences in given scenarios. Content may include the following:- PDAs

1.10 Determine the issues that must be considered when upgrading a PC. In a given scenario, determine when and how to upgrade system components.- Laptop power sources-- Lithium ion-- NiMH-- Fuel cell- PCMCIA Type I, II, III cards

DOMAIN 2 Diagnosing and Troubleshooting

2.1 Recognize common problems associated with each module and their symptoms, and identify steps to isolate and troubleshoot the problems. Given a problem situation, interpret the symptoms and infer the most likely cause.- Portable Systems-- PCMCIA-- Batteries-- Docking Stations/Port Replicators-- Portable unique storage

12) NETWORKINGNetworking is connecting two or more devices to allow communication between them with the purpose of sharing information and resources. Examples of these devices are computers, printers, routers, hubs, modems, and PDAs. The information and resources being shared can be anything from MS Office documents and e-mail to printers and fax devices. Internetworking is connecting multiple networks with the purpose of creating one large network. The Internet is the most common example of an internetwork.

Client/server vs Peer-to-peerMost of today's networks use the client/server model. In this model at least one computer acts as a server. Servers hold resources that are accessed over the network by clients. Examples of resources are shared files, e-mail messages and even applications. Another common server is the print server that allows access to network printers.In a peer-to-peer network model every computer can act as a client and a server at the same time. An example is a network with 4 Windows XP Professional computers in a workgroup using file and print sharing.

LAN/WANThe terms LAN and WAN mainly refer to the geographical area of the network. LAN is short for Local Area Network and is a high-speed network typically within a building. WAN is short for Wide Area Network and refers to low-speed networks that cover a large distance, for example a network that spans several cities or the entire globe even. The Internet can be considered the largest WAN, but actually consists of many different WANs, which, in turn, include LANs. The connection between LANs in an internetwork is also referred to as a WAN connection, although a network diagram of a WAN often includes the LANs in it.

Private vs Public NetworksTwo other terms used to categorize networks are private networks and public networks. A private network is typically within the premises of a corporation and can be accessed only by users working for, or related to, that corporation. A public network Internet can be accessed by multiple individuals and/or corporations, the best example of a public network is again, the Internet.

Media The physical connection used to transport electrical signals (bits; 1s & 0s) between the network devices is called the media. Examples of network media are copper cabling, fiber optic cabling and infra-red. The most common types of media are outlined later in this TechNote.

ProtocolsTo be able to communicate with each other, network devices need a common language. The language network devices use is called a protocol. There are many different types of protocols available, and most protocols are actually a suite of several protocols, each with a different function. For example, one protocol allows data transfer between hosts and another can be used to retrieve email from a mail server. Today's most common protocol, TCP/IP, and several older, less common protocols, are described later in this TechNote.

AddressingIf you want to contact somebody by snail-mail or by telephone you need some sort of address. In a telephone network you need to enter a telephone number to reach your intended communication partner. Similar, devices in a network need an address. There are two types of addresses, the first type is configured in software by a network administrator and uses protocols to define the addressing scheme and format, this type is known as network or layer 3 addressing. The other type of address that devices in a network use, is most commonly referred to as MAC address; this address is burned into the chip of the physical network interface.

Network TopologiesA physical topology depicts how network devices are connected physically, the cabling.A logical topology depicts the route a the signal takes on the network.

Bus - Devices are connected to a central cable, in this type of network both cable ends are terminated.

Star - Devices are connected through a central hub. The hub forms a single-point-of-failure.

Ring - Every device is connected to two other devices, forming a ring.

Mesh - In a full mesh every device in the network is connected to every other device. In reality a partial mesh is often used in backbone environments.

CollisionsA collision indicates that two or more network nodes have tried to access the network simultaneously, and both put a signal on the network cable at the same time which collide with each other. Occasional occurrences are normal and will not affect network performance.

Access MethodsThe access method defines how signals are put on the network media.

Carrier Sense Multiple Access with Collision Detection (CSMA/CD)The access method used in Ethernet networks. In so called broadcast networks multiple nodes are attached to the same cable segment. To avoid that nodes on the network transmit traffic simultaneously and their signals collide, they listen to the network to sense if it is currently in use. If a collision does occur, it will be detected and the sender will wait for an amount of time determined by a backoff algorithm.

Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)The access method used in Wireless networks for example. It is similar to CSMA/CD, but CA means that a node broadcasts a warning it is about to use the network, before it actually starts to transmit data.

Token PassingThis is the access method used in Token Ring and FDDI networks. A token is passed around the network from station to station, when a station does not need to transmit data it passes the token to the next station in the logical ring. A station that receives the token and needs to transmit data seizes the token and sends a data frame, the receiving station marks the data frame as read and passes it forward along the ring to the source station. During this time no other station can transmit data which rules out collisions. The source station releases the token (passing it to the next station) when it receives the data frame and verified it was read.

NETWORK INTERFACE CARDS (NICs)

A Network Interface Card (NIC), typically an expansion card in a computer, is used to connect to the physical network media. Some mainboards and most portable computers are equipped with a built-in (onboard) NIC. NICs are available for different types of network media, the most common today being Ethernet NICs with a RJ-45 socket for UTP/STP cabling. To install a network interface card you need a free ISA or PCI expansion slot and an appropriate driver that the computer's operating system will use to communicate with the NIC. Some older ISA NICs can be manually configured to use a particular IRQ. This is done by setting jumpers or dip switches. Some other NICs allow the IRQ to be configured through the use of configuration software.Media Access LayerINCLUDEPICTURE \d "/images/nic.gif"

An image of a Fast Ethernet network interface card.

Many of today's NICs are equipped with status indicators in the form of leds. These leds can be used to troubleshoot network problems. Typically one green led indicates the NIC is physically connected to the network and flashes when activity occurs, i.e., the port is transmitting or receiving data, this is also known as a heartbeat. When the NIC supports multiple speeds, for example 10 and 100 Mbps, there can be a green led for each speed, of which one is lit indicating the current speed, possibly auto-negotiated with a hub or switch. Some NICs, as well as other network devices such as hubs, include and orange or red led which flashes when collisions occur. If the collision LED flashes repeatedly or continuously, the NIC maybe be configured incorrectly or may be malfunctioning, or there may be other devices utilizing the network heavily.

As described earlier, networks interfaces are physically configured with an address known as the MAC address (MAC is short for ), layer 2 address, Burned In Address (BIA), or physical address. Here's an example of a MAC address: 00-10-E3-42-A8-BC. The first 6 hexadecimal digits specify the vendor/manufacturer of the NIC, the other 6 define the host. MAC addresses are supposedly unique across the planet.

Half duplex vs. Full-duplex communication

Half-duplex means that only one host can communicate at a given time, two hosts communicating with each other will take turns transmitting. In full-duplex communication both hosts can transmit at the same time, in theory allowing twice as much data to be transmitted over the same connection.The connections able to run at full-duplex are cross-cable connections and connections to a port on a switch, where collisions cannot occur because each end has it's own wire pair (separate segment).

MEDIAThe list below shows some important considerations to make when choosing the proper media for a particular network solution:

CostBesides the high cost of some cable types you also have to consider that the equipment that is used to put the signal on the cable, and take it off the cable, differs a lot in price.

Maximum distanceNetwork media is bound to a maximum cable length, because when a signal travels through the cable it will get weaker.

FlexibilitySome types of media are more flexible than others. Typically, the thinner the cable the easier it is to implement. Except for fiber optic cabling, this has to be placed with care to avoid breaks.

Susceptibility to electrical interferenceSome cables, such as UTP, are more susceptible to nearby high-voltage devices or other sources of electrical interference, than other cables, such as STP or fiber-optics.

Susceptibility to cross-talkCross-talk refers to interference from other data cables.

Susceptibility to fire.Plenum cabling is designed to better withstand the introduction of fire than PVC, and, if burned, generates less smoke toxicity as a result. It is less flexible and it is more expensive. Plenum is typically used in environments such as hospitals.

RS-232The RS-232 standard specifies serial cabling using DB-9 or DB-25 connectors. The maximum length for a RS-232 cable is 50 feet (15.25 meters) at a baudrate of 19200. The RS-232 standard is designed to supports data transfer rates up to 20 Kbps.

TWISTED PAIRThe most common type of twisted pair cabling is Unshielded Twisted Pair (UTP) cabling. This type of cabling is typically made up of 4 twisted pairs of copper wires as depicted in the image below. Each wire has its own cover, and so does the complete bundle.

UTP cabling is categorized using a number. The required category depends on the network technology and the desired transmission speed. Following are the UTP categories:

Cat.1Used for voice/telephone communication only.

Cat.2Data rates up to 4 Mbps.

Cat.3Data rates up to 4 Mbps in TokenRing networks, 10 Mbps in Ethernet networks, bandwidth of 16 MHz.

Cat.4Data rates up to 16 Mbps in TokenRing networks, 10 Mbps in Ethernet networks, bandwidth of 20 MHz.

Cat.5Data rates up to 100 Mbps, bandwidth of 100 MHz

Cat.5eData rates up to 1 Gbps (Gigabit Ethernet), bandwidth of 100 MHz rated (tested up to 350 Mhz).

Cat.6Data rates up to 1 Gbps (Gigabit Ethernet), bandwidth of 250 MHz rated (tested up to 550 Mhz).

Another, more expensive type of twisted pair cabling is Shielded Twisted Pair (STP). STP cabling includes a metal cover shielding the bundle of wires, reducing electrical interference and cross-talk.

In a cross-over cable wire 1 & 3, and 2 & 6 are crossed, these cables are typically used to connect a pc to pc, or switch to switch for example.

UTP cabling in networks use RJ-45 connector as depicted below:

RG-58U50 Ohm, used in 10Base2 Ethernet networks (Thinnet).

RG-850 Ohm, used in 10Base5 Ethernet networks (Thicknet).

RG-59 / RG-675 ohms, used for cable television (hence, cable modem access), video, digital audio, and telecommunication applications (for example for E1 coaxial cabling).

10Base2Commonly referred to as Thinnet, uses a bus topology. Stations are attached using BNC T-connectors represented in the picture below. Both cable ends are terminated using a 50 ohm terminator.

AUI connectorsMAU transceiver

10Base5 specifications:- Maximum segment length is 500 meters - Maximum data transfer speed is 10Mb/s- 0.4 inch, 50 ohm coaxial RG-8 cabling (Thicknet)

FIBER OPTICFiber optic cabling is a rather new technology that allows for fast data transfer over large distances. Fiber optic cabling is not susceptible to electrical interference, but needs expensive equipment and is fragile. There are two main types of fiber optics, the first is multi-mode, which is typically used in corporate networks' backbone. In a multi-mode cable, light travels down the fiber cable in multiple paths. Essentially, the light beam is reflected off the cladding (material surrounding the actual fiber) as it travels down the core. The other type is single-mode, this type is typically used by telephone companies to cover very large distances. In a single-mode cable, light travels thru the cable without interacting with the glass cladding (material surrounding the actual fiber), maintaining signal quality for great distances.

Fiber optic cabling is connected using SC, ST or MIC connectors.

SC connectorsST connectorsMIC connectors

Network technologies that use fiber optic cabling include 100BasesFX and FDDI.

100BaseFX (802.3u)Similar to 100BaseTX but designed to operate over 2 strands of single-mode or multi-mode fiber cabling. One cable is used to send the other is used for collision detection and receiving. The maximum length of a 100BaseFX link is 400 meters in half-duplex mode, 2000 meters in full-duplex mode.

- 1000BaseLX, uses multi-mode fiber with a maximum length of 550 meters or single-mode fiber with a maximum length of 5 km- 1000BaseSX, uses multi-mode fiber with a maximum length of 500 meters

FDDIAnother token-passing network technology is Fiber Distributed Data Interface. FDDI networks are often used as backbones for wide-area networks providing data transfer rates up to 100 Mb/s using fiber media. The use of fiber makes it immune to electrical interference, and allows it to transmit data over greater distances. FDDI provides fault tolerance by using a dual counter-rotating ring configuration, an active primary ring and a secondary ring used for backup.

WIRELESS

InfraredInfrared (IR) communication is typically used between devices such as PDAs, laptops and printers. An advantage of IR communication is that it is not susceptible to electrical interference. The main disadvantage, besides the rather short maximum supported distance between devices, is that there must be a clear path between the devices. Supports data transfer rates up to 4 Mbps.

802.11b (Wi-fi)The 802.11b standard specifies wireless Ethernet LAN technology. The topology used in wireless networks is known as cellular. It is a wireless structure where stations send signals to each other via wireless media hubs. The access method for 802.11b is CSMA/CA. Clients connect via wireless access points with data transfer rates up to 11 Mbps. 802.11b operates in the 2.4 GHz range. Another WLAN standard that has recently emerged, 802.11a, offers a maximum transmission speed of 54 Mbps at 5 GHz frequency.

NETWORK COMPONENTS

RepeatersUsed to extend the maximum distance a cable segment can span. Repeaters grab the incoming electrical signal from the cable, amplify it, and send it out.

HubsHubs, also known as concentrators or multiport repeaters, are used in star/hierarchical networks to connect multiple stations/cable segments. There are two main types of hubs: passive and active. An active hub takes the incoming frames, amplifies the signal, and forwards it to all other ports, a passive hub simply splits the signal and forwards it.

BridgesUsed to increase network performance by segmenting networks in separate collision domains, or increase the network size. Bridges are not aware of upper-layer protocols such as TCP/IP or IPX/SPX. They keep a table with MAC addresses of all nodes, and on which segment they are located.

SwitchesSimilar to bridges; they also keep a table with MAC addresses per port to make switching decisions. The main difference is that a switch has more ports than a bridge, and instead of interconnecting networks it is typically used to connect hosts and servers like a hub does, but offers dedicated bandwidth per port, hence offers much higher network performance than hubs.

RoutersRouters are used to interconnect multiple (sub-)networks and route information between these networks by choosing an optimal path ("route") to the destination based on addressing information from protocols such as TCP/IP or IPX/SPX. Router are also typically used to connect a LAN to a WAN or another LAN, which can use different technologies such as Token Ring, Ethernet, ISDN, Frame Relay etc.

GatewaysUsed to connect networks with dissimilar technologies, for example a Microsoft TCP/IP network and NetWare IPX/SPX network can be connected using a gateway. Typically implemented in software on a router.

FirewallsProtects a private network from external users, typically those from the Internet, by hiding the internal network and filtering incoming packets. A firewall is not always a hardware device, it can be implemented in software on a router or proxy server as well.

PROTOCOLSTCP/IPTCP/IP is today's most popular network protocol and is the protocol in the Internet. It is a routable protocol that provides connection between heterogeneous systems, these are the main reasons the protocol is so widely adapted; for example it allows communication between UNIX, Windows, Netware and Mac OS computers spread over multiple interconnected networks. The "TCP/IP protocol" is actually the "TCP/IP suite" composed of many different protocols each with its own functions. The two main protocols are in its name: the Internet Protocol and the Transmission Control Protocol.

IP addressing is assigning a 32-bit logical numeric address to a network device. Every IP address on the network must be unique. An IP address is represented in a dotted decimal format, for example: 159.101.6.8. As you can see the address is divided in 4 parts, these parts are called octets.

The current used addressing schema in version 4 of IP is divided in 5 Classes:

ClassesFirst Octet

Class A1126

Class B128191

Class C192223

Class D224239

Class E240254

A subnet mask is used to determine which part is the network part and which is the host part.

Default subnet masks:

Class A255.0.0.0

Class B255.255.0.0

Class C255.255.255.0

IANA reserved 4 address ranges to be used in private networks, these addresses won't appear on the Internet avoiding IP address conflicts:- 10.0.0.0 through 10.255.255.255- 172.16.0.0 through 172.31.255.255- 192.168.0.0 through 192.168.255.255- 169.254.0.1 through 169.254.255.254 (reserved for Automatic Private IP Addressing)

IPX/SPX

Although current versions of Novell Netware use TCP/IP, before Netware version 5, IPX was the protocol in Netware networks. It is a small and easy to implement routable protocol developed by Novell and based on the Xerox Network System. The Netware protocol suite is a suite of several protocols for different functions, the most important being IPX and SPX. IPX is similar to the Internet Protocol from the TCP/IP suite, it is a connectionless Layer 3 (Network layer) protocol used to transfer datagrams between hosts and networks. SPX is the Transport protocol used to provide reliable transport for IPX datagrams, similar as TCP does for IP.

The frame types of two Netware hosts must match to enable communication without a router. IPX can use several frame formats, of which the two most important are listed in the following table.

Frame FormatFrame TypeNetware Versions

Novell 802.3 raw802.3Default frame type for Netware 3.11 and earlier. Supports only IPX/SPX as the upper layer protocol

IEEE 802.3802.2Default frame type for Netware 3.12 and 4.x. The main difference with Novell's 802.3 format is the addition of LLC field, which specifies the upper-layer protocol, such as IPX or IP.

An complete IPX network address is 80 bits in length and is represented in a hexadecimal format. As with all routable protocols it needs a network and a host portion, the network portion is 32 bits in length and is manually configured. The host portion is 48 bits in length and is derived from the MAC address of the host's network interface.

Examples of complete IPX internetwork addresses are:- 0CC001D8.0050.BF61.6C71- 0000ABBA.0060.9736.954B- 00000046.0060.E92A.C2A4

NWLINK is Microsoft's implementation of IPX/SPX which allows Windows clients to communicate with Netware servers.

AppleTalkAppleTalk was developed by Apple Computers in the early 1980s to allow file and printer sharing and mail functionality between Macintosh computers. A Mac that shares resources is called a server, and the computer connecting to it a client. Like TCP/IP, AppleTalk is not just one protocol, but a suite of several protocols for different functions. It is built-in in every Macintosh computer and requires virtually no user interaction, therefore it is very easy to administer in small network environments. Address assignment in AppleTalk networks is automatically. Besides Ethernet and TokenRing, AppleTalk can also be used on Apple's own network technology called LocalTalk, which uses UTP/STP cabling.

NetBEUI/NETBIOSNETBios Extended User Interface is a non-routable Transport layer protocol. The reason it is non-routable is in its flat addressing schema, NETBEUI uses Netbios names to identify computers on the network that do not contain a network portion. Netbios names are sometimes referred to as friendly names. NetBIOS names are 16 characters in length and cannot contain any of the following characters: \ / : * ? " < > | The first 15 characters represents a unique name identifying a resource, the 16th character (if you would set a name of 8 characters it is padded with spaces up to 15 characters long to allow a '16th' character) is a suffix identifying the type of resource or group of resources. For example the redirector, server, or messenger services can be installed on one computer resulting in three times the same name but with different suffixes.NETBEUI is a broadcast protocol, meaning a computer running NETBEUI discovers the MAC address from the intended communication partner by sending out a broadcast with the NETBIOS name. The main advantage of NETBEUI is that it is small in size and easy-configurable.

Current related exam objectives for the 2003 A+ Core exam.DOMAIN 6.0: Basic Networking6.1 Identify the common types of network cables, their characteristics and connectors.Cable types include:- Coaxial--- RG6--- RG8--- RG58--- RG59- Plenum/PVC- UTP--- CAT3--- CAT5/e--- CAT6- STP- Fiber--- Single-mode--- Multi-modeConnector types include:- BNC- RJ-45- AUI- ST/SC- IDC/UDC

6.2 Identify basic networking concepts including how a network works.Concepts include:- Installing and configuring network cards- Addressing- Bandwidth- Status indicators- Protocols--- TCP/IP--- IPX/SPX (NWLINK)--- AppleTalk--- NETBEUI/NETBIOS- Full-duplex, half-duplex- CablingTwisted Pair, Coaxial, Fiber Optic, RS-232- Networking models--- Peer-to-peer--- Client/server- Infrared- Wireless

6.3 Identify common technologies available for establishing Internet connectivity and their characteristics.

Technologies include:- LAN- DSL- Cable- ISDN- Dial-up- Satellite- Wireless

Characteristic include:- Definition- Speed- Connections

Current related exam objectives for the 2002 A+ Core exam.DOMAIN 6.0: Basic Networking

This domain requires knowledge of basic network concepts and terminology, ability to determine whether a computer is networked, knowledge of procedures for swapping and configuring network interface cards, and knowledge of the ramifications of repairs when a computer is networked. The scope of this topic is specific to hardware issues on the desktop and connecting it to a network.

6.1 Identify basic networking concepts, including how a network works and the ramifications of repairs on the network.

Content may include the following:- Installing and configuring network cards- Network access- Full-duplex, half-duplex- CablingTwisted Pair, Coaxial, Fiber Optic, RS-232- Ways to network a PC- Physical Network topographies- Increasing bandwidth- Loss of data- Network slowdown- Infrared- Hardware protocols

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