IEEE 802.11

IEEE 802.11 is the standard that specifies connectivity for wireless networks. IEEE 802.11, or Wi-Fi, refers to a collective group of standards, as shown in the figure.

These protocols specify the frequencies, speeds, and other capabilities of the different Wi-Fi standards.

System board?

A "system board" is another name for motherboard. Therefore integrated and non-integrated system boards are two types of motherboards.

An integrated system board has multiple components integrated into the board itself. These may include the CPU, video card, sound card, and various controller cards.

A non-integrated system board uses installable components and expansion cards. For example, a non-integrated system board may allow you to upgrade the video card by removing the old one and installing a new one. Non-integrated motherboards typically have several PCI expansion slots as well.

Most laptop use fully integrated system boards, since they provide a smaller form factor than non-integrated boards. Desktop computers often use non-integrated motherboards, though they may contain some integrated parts. For example, most modern motherboards used in desktop computers have an integrated sound card and controller cards. Some may even have an integrated processor and video card as well.

Since non-integrated system boards often have some integrated components, it is difficult to define the exact difference between the two types. In fact, it may be more accurate to refer to a non-integrated system board as a partially integrated system board. Still, when it comes to technical specifications, it can be helpful to know what the difference is between integrated and non-integrated motherboards. While there is no official definition of either type, here is what I have found:

In most cases, the difference comes down to the video card. If a motherboard has an integrated graphics processor, it is generally considered to be an integrated motherboard. If the graphics processor resides on a removable card, then the motherboard is considered to be non-integrated. Therefore, when you see the terms "integrated" or "non-integrated" in technical specifications, you can at least tell what type of graphics processor the system uses.

[tag mother board, system board, mainboard]

Computer Ports

All desktop computers have ports which are used to plug external devices into the computer such as monitors, keyboards, printers and scanners.

  • USB– Used for the majority of peripherals. Designed to be a universal connector, to be compatible with any device.
    • Ethernet– Used for networking and board band Internet connections.
  • Modem– Used for data access via a telephone line (eg. Dial-up Internet connections). Slowly being replaced by broadband connections as dial-up becomes an obsolete technology.
    • Headphone jack – Used for connecting sound devices. (USB can also be used)
  • Serial – Used for connecting any device that uses a serial connector. These are being replaced by USB.
  • Parallel– Used for connecting any device that uses a parallel connector. These are being replaced by USB.
    • PS/2– Used for computer mice and keyboards (These are being replaced by USB)
    • Video (VGA) – Used for connecting a monitor / projector with analog signal.
  • Digital Video Interface (DVI) – Used for connecting a monitor, but keeps in the signal in digital format. Usually used for LCD displays.
    • Power – Used for connecting the power lead.
    • Firewire/IEEE 1394 – Used for connecting external hard drives and camcorders.
  • Card Reader– used to read flash memory cards belonging to digital cameras, mobile phones, music players etc.

Advantages of Desktop Computer

  • Cost. Getting a cheap but reliable desktop computer is much easier than getting a cheap but reliable notebook computer. This is less true than it used to be, as notebooks are becoming more affordable. However, dollar for dollar, you get more for your desktop buck than for your laptop buck. Desktop computers also are less expensive to upgrade.
  • Speed. Dollar for dollar, desktops are faster. You can get a fast laptop, but it will cost you.
  • Cheaper and easier to repair. If a spill a Coke on your desktop keyboard, you’ll need to spend $15 on a new keyboard. If you spill a Coke on your laptop keyboard, well, you’ll be lucky if you still have a working laptop.
  • Much more difficult to steal than a laptop computer. This can be a huge advantage on a college campus, where theft often is a problem.
  • More ergonomically correct. Generally speaking, desktops are easier on your eyes, hands, and backs. Students spend a good deal of time on their computers, so this is an important consideration.
  • Nothing to lug around. Speaking of ergonomics, lugging a heavy laptop computer around campus isn’t good for your back either. Yes, you can get lightweight laptops, but they’ll cost you.
  • Less easy to damage. Sure, if you drop your desktop computer, you’re going to damage it. But how likely is that compared to the likelihood of dropping your laptop?

Computer Word Families





Ex: The best time to access the internet is early in the morning.



Ex: To gain access to the computer lab, all users must have a valid ID.



Ex: The staff assistant always keeps the door to her office open to show she is accessible.





Ex: If we work hard, we can duplicate last year’s sales records for computers.



Ex: Don’t worry, I have a duplicate on my hard drive.



Ex: His success at our company was based on the duplication of management techniques he had used elsewhere in his career.





Ex: We failed to tell you that your records were deleted.



Ex: The power failure caused the system to shut down.



Ex: Everyone can make a mistake. Even a computer is fallible.





Ex: We were warned that our E-mail was not private.



Ex: The warning was written on the box.



Ex: The warning signs were all there; we should have paid attention to them.


Learn Computer Vocabulary

Match (Number to Letter)

1. To access (v)

2. To allocate (v)

3. Compatible (adj)

4. To delete (v)

5. Display (n)

6. To display (v)

7. To duplicate (v)

8. To fail (v)

9. To figure out (phr)

10. To ignore (v)

11. To search (v)

12. To shut down (v)

13. To warn (v)

a). to obtain; to gain entry

b). to alert; to tell about a danger or problem

c). to remove; to erase

d). able to function together

e). not to succeed; not to work correctly

f). to show

g). what is visible on a monitor

h). to produce something equal; to make identical

i). to look for

j). to understand; to solve

k). not to notice; to disregard

l). to designate for a specific purpose

m). to turn off; to cease operations



1. a

2. l

3. d

4. c

5. g

6. f

7. h

8. e

9. j

10. k

11. i

12. m

13. b

Computer Hardware

+ Computer HardWare : PC components such as Monitor, Keyborad, Mouse , System Unit. គេសំដៅទៅលើគ្រឿងបន្លាស់របស់ PC មានដួចជា: Monitor, Keyboard, Mouse , System unit (​ គឺជាគ្រឿងបន្លាស់ដែលបានផ្តុំចួលគ្នា ) ។


  • Input Device Computer : និយាយសំដៅទៅលើឧបករណ៍ដែលមានតួនាទីសំរាប់ញ្ចូលពត័មាន រឺ ទិន្នន័យ

ចូលទៅក្នុង PC ដែលមានដូចជា : Keyboard, Scanner, Phone, Camera, Flash…..

  • Output Device Computer : និយាយសំដៅទៅលើឧបករណ៍ដែលមានតួនាទីសំរាប់នាំពត័មាន រឺ

ទិន្នន័យ ចេញពីរ PC មកខាងក្រៅ​ដែលមានដូចជា​ : Printer, Monitor, Speaker ….

+ Computer Software : សំដៅលើកម្មវិធីរបស់​ PC ហើយ Software ដែលយើងបញ្ចូលទៅក្នុង PC មាន​ 2​ ប្រភេទ :

  • OS ( Operation system ) : គឺជាប្រព័ន្ធដំណើរការរបស់​ PC ​​ដែលគេហៅថា : Windows, Linux, Max …
  • Application Software : គឺជាកម្មវិធីដែលដំណើរការលើ OS ដែលគេហៅថា Programs មានដូចជា

Ms.Office, Adope Photoshop, Game…

  • Software សំខាន់ៗក្នុង PC របស់យើងមានដូចជា​ :
    • BIOS or CMOS
    • OS
    • Application Software

+ តំរូវការចាំបាច់របស់ PC Hardware : ដើម្បីអោយ PC មួយដំណើរការបានយើងចាំបាច់ត្រូវមាន : Monitor, Keyboard, Mouse, System unit ( HDD, FDD, CD-ROM, Power Supply, CPU, Mainboard, Ram, System case ) ..

+ មុនងារ និង តួនាទីរបស់ Computer Hardware

  • Monitor : មានតួនាទី​សំរាប់បង្ហាញពត័មាន​ រឺ ទិន្នន័យផេ្សងៗ ចេញពីរ System unit តាមរយះ Port VGA។

Monitor ចែកចេញជា​ 2​​ ប្រភេទ :

  • CRT
  • LCD
  • Keyboard :​ មានតួនាទីជាអ្នកបញ្ចូលពត័មាន រឺ ទិន្នន័យចូលទៅក្នុង PC ។

Keyboard ដែលគេភ្ជាប់ទៅនឹង System Unit មាន​ 2 ប្រភេទ​ :

  • USB
  • PS/2
  • Mouse : មានតួនាទីជាអ្នក អូស​ រឺ ទាញ​រូបភាព និង ប្រើសំរាប់កំណត់ និង ជ្រើសរើសអី្វមួយ ។

Mouse ដែលភ្ជាប់ទៅនឹង System unit មាន 3 ប្រភេទ :

  • USB
  • PS/2
  • Serial
  • HDD ( HARD DISK DRIVE ) :ជាឧបករណ៍មួយសំរាប់ផ្ទុកទិន្នន័យ​ រឺ ​ពត័មានផេ្សងៗដែលយើងបានបញ្ចូល​.​

HDD កាន់តែធំការផ្ទុកទិន្នន័យបានកាន់តែច្រើន ។
គេគណនាខ្នាតរបស់ HDD គិតជា Megabyte, GigaByte, Terabyte HDD គេចែកចេញជា 2 ប្រភេទ :

  • External Hard Disk : ជាឧបករណ៍មួយដែលនៅខាងក្រៅSystem Unit វាមាននាទីសំរាប់​ផ្ទុក​ទិន្នន័យ រឺ​ ចំលងទិន្នន័យពីរ PC មួយទៅ PC​ មួយទៀត តាមរយះ Port USB .
  • Internal Hard Disk : ជាឧបករណ៍មួយដែលគេប្រើវានៅខាងក្នុង System unit​ ដែលមានដូចជា :

        // IDE Hard Disk : ( Pentium II – IV )

        // SATA Hard Disk : ( Pentium IV )

        // SCSI Hard Disk : ( SERVER )

  • FDD ( FLOPPY DISK DRIVE ) : ជាឧបករណ៍មួយដែលសំរាប់អានទិន្នន័យ រឺពត័មានចេញពីរ Diskette​

Diskette ជាឧបករណ៍សំរាប់ផ្ទុកទិន្នន័យ

ត្រឹមតែ 1,44MB តែប៉ុណ្ណោះ

  • CD-ROM ( Compact Disk Read Only Memory ) ជាឧបករណ៏មួយដែលសំរាប់អានទិន្នន័យ
    ចេញពីរ CD .

CD-ROM ចែកចេញជា 2 ប្រភេទ :

  • Internal CD-ROM ជាប្រភេទ CD-ROM ដែលប្រើនៅខាងក្រៅ System unit តាមរយះ​ Port USB
  • External CD-ROM ជាប្រភេទ CD-ROM ដែលប្រើនៅខាងក្នុង System unit ដែលមានដូចជា ;

    // IDE CD-ROM :​ ដែលគេប្រើជាទូទៅ

    // SATA CD-COM : ( Pentium IV )

    // SCSI CD-ROM : ( Server )

  • Power Supply ; ជាឧបករណ៍សំរាប់បំលែងចរន្តភ្លើងពីរ AC -> DC និង​
    សំរាប់ផ្គត់ផ្គង់ ចែកចាយចរន្តភ្លើង អោយទៅ Hardware ដូចជា : HDD, FDD, CD-ROM, MAINBOARD…

    +    Power Supply ; គេចែកចេញជាពីរប្រភេទ​​ :

    • Power Supply ប្រភេទ AT នឹង ប្រភេទ​ ATX

      / ប្រភេទ AT ប្រើជាមួយ Pentium II តែប៉ុណ្ណោះ ហើយការ Shutdown របស់វាមិន Auto ទេ

      / ប្រភេទ​ ATX ប្រើទូទៅនៅលើ Computer នាពេលបច្ចុប្បន្ន​ហើយការ Shutdown របស់វា Auto

      / ខ្សែដែលដោតទៅ HDD, CD-ROM មានបូនសរសៃ គឺ ;

      _    ពណ៍ក្រហម ​​ 5

      _    ពណ៍ខ្មៅ​​​​    0

      _    ពណ៍ខ្មៅ    0

      _    ពណ៍លឿង    12

  • CPU ( Central Processing Unit ) ជាធាតុផ្សំម្យ៉ាងនៃ Hardware Computer ដែលមានតួនាទីយ៉ាងសំខាន់ ដែលមិនអាចអត់វាបាន CPU មាននាទីជាអ្នកគិត និង​ ដោះស្រាយរាល់បញ្ហារបស់ Computer កាលណា CPU កាន់តែខ្ពស់ PC កាន់តែមានល្បឿនលឿន​ ហើយគេគណនាខ្នាតវាជា MHz and GHz

    +    Pentium II = 100MHz –> 450MHz

    +    Pentium III = 450MHz –> 1133MHz or 1.1GHz

    +    Pentium IV = 1.4GHz —> 3.6GHz

    / ជាទូទៅគេបែងចែកវា
    ប្រភេទ​ ;

    • CPU ប្រភេទ Slot ប្រើលើ Pentium II & III
    • CPU ប្រភេទ Socket ប្រើលើ Pentium II –> IV
    • CPU ប្រភេទ LGA ប្រើលើ Pentium IV
  • Motherboard : ជាបន្ទះធំជាងនៅក្នុង System case មាននាទីសំរាប់គ្រប់គ្រង និង ភ្ជាប់ Hardware ទាំងអស់អោយធ្វើការរួមគា្ន​

    គេបែងចែកជា 2 ប្រភេទគឺ :

    • Motherboard ជាប់ ដែលមាន Sound, VGA, LAN ភ្ជាប់មកជាមួយ
    • Motherboard ដាច់ដែលមិនមាន​ Sound និង​VGA ជាប់មកជាមួយ

    លក្ខណះរួមរបស់ Motherboard :

        +    Port រួមមាន:

            / Port : PS/2 សំរាប់ភ្ជាប់ជាមួយ Mouse និង​ Keyboard

            / Port : Serial សំរាប់ភ្ជាប់ជាមួយ Mouse, Modem

            / Port : Parallel : មានពណ៏ស្វាយភ្ជាប់ជាមួយ Printer

            / Port : USB ភ្ជាប់ជាមួយ keyboard, Mouse and External….

            / Port : VGA ភ្ជាប់ជាមួយនិង Monitor

            / Port : Network ភ្ជាប់ជាមួយនិង​ PC

            / Port : Sound មានបីពណ៏ខុសៗគ្នា ប្រើសំរាប់ភ្ជាប់និង Speaker ..



    +    Slot រួមមាន :

        / Slot : Simm ប្រើជាមួយ Ram S-Ram

        / Slot : Rimm ប្រើជាមួយ Ram RD-Ram

        / Slot : Dimm ប្រើជាមួយ SD-Ram, DDR-Ram, DDR2-Ram

        / Slot : ISA ប្រើជាមួយ Sound Card, Modem Card, Network Card…

        / Slot : PCI ប្រើជាមួយ VGA CARD

        / Slot : AGP ប្រើជាមួយ VGA CARD

        / Slot : PCI Express ប្រើជាមួយ VGA CARD

        / Slot : CPU ប្រើជាមួយ CPU
    ប្រភេទ Slot

  • RAM ( Random Access Memory ) ជាអង្គចងចាំបណ្តោះអាសន្ននៅពេល PC ដំណើរការ មិនតែប៉ុណ្ណោះ វាមាននាទីជាអ្នកជំរុញអោយ PC មានល្បឿនលឿន​ផងដែរ។ គេគណខ្នាតរបស់វា
    គិតជា MB & GB

    Ram មានជើងទាំងអស់ បី ប្រភេទ​:

    • Simm ប្រើជាមួយ Pentium II តែប៉ុណ្ណោះ ដែលប្រើជាមួយ Ram ប្រភេទ S-RAM .
    • Rimm ប្រើជាមួយ Pentium III, IV ដែលប្រើជាមួយ Ram ប្រភេទ RD-RAM ដែលជា RAM​ ប្រើជាគូរ
    • Dimm ជាប្រភេទ Ram​ ដែលគេប្រើជាទូទៅនាពេលបច្ចុប្បន្ន
      ដែលមានដូចជា​ :

      /    SD-Ram ( P II,III ) ទំហំខ្ពស់បំផុត 512MB មានជើង 168 Pins

      /    DDR-Ram​ ( PIV ) ទំហំខ្ពស់បំផុត 1GB មានជើង 184 Pins

      /     DDR2-Ram ( PIV ) ទំហំខ្ពស់បំផុត 2MB មានជើង 240 Pins

        _ Ram ទាំងអស់មាន 5 ប្រភេទ ;

  • S-RAM
  • RD-RAM
  • SD-RAM
  • DDR2-RAM
  • VGA ( Video Graphic Adapter ) ជាឧបករណ៍មួយសំរាប់បញ្ជូនពត័មាន រឺ
    ទិន្នន័យផេ្សងៗ ចេញពីរ System unit ទៅ Monitor រឺ TV . VGA កាន់តែខ្ពស់ធើ្វអោយរូបភាពកាន់តែច្បាស់។ គណនាខ្នាត VGA ជា​: MB, GB . គេបែងចែក VGA ជាពីរប្រភេទ​ :
    • VGA on Board : ជាប្រភេទ VGA ដែលជាប់ជាមួយនិង Board ដែលយើងមិនអាចផ្លាស់ប្តូរបាន ប៉ុន្តែអាចទាញទំហំពីរ Ram បាន

    • VGA CARD : ជាប្រភេទ​ VGA ជាបន្ទះ Card ដែលគេប្រើនៅលើ Slot ហើយ VGA Card គេបែងចែក ជាបីប្រភេទ ;

      /    VGA CARD PCI ( P II –> IV )

      /    VGA CAR AGP ( P III –> IV )

      /     VGA CARD PCI EXPRESS ( PIV )

  • Sound Card មាននាទីជាអ្នកបញ្ជូនសំលេងអោយទៅ Speaker និង
    ឧបករណ៍ផេ្សងៗទៀតដែលអាចបន្លឺ សំលេងបានមិនតែប៉ុណ្ណោះ Sound ក៏អាចបញ្ចូលសំលេងមកក្នុង PC​ បានដែរ

    Sound Card​ មានពីរប្រភេទ ; ISA, PCI

  • Network Card មាននាទីសំរាប់ភ្ជាប់បណ្តាញ PC ពី PC មួយទៅ PC មួយដើម្បីអោយ PC ទាំងអស់នោះធ្វើ ការរួមគា្ន Network Card មានពីរប្រភេទ ; ISA, PCI
  • Modem មាននាទីជាអ្នកភ្ជាប់បណ្តាញ Internet & Phone ហើយ Modem គេបែងចែកជាពីរប្រភេទ ;
    • External Modem ជាប្រភេទ Modem ដែលប្រើភ្ជាប់តាមរយះ Port USB & Serial .
    • Internal Modem ​ជាប្រភេទ Modem ដែលប្រើខាងក្នុង System Unit ដោយប្រើជាបន្ទះ Card
  • ថ្ម CMOS មាននាទីចងចាំពេលវេលា ថ្ងៃខែឆ្នាំ នឹង
    ចងចាំកម្មវិធីរបស់ CMOS
  • Jumper : មាននាទី សំរាប់ភ្ជាប់ចរន្តពីរជើងមួយទៅជើងមួយ


BIOS all information go here…

BIOS means Basic Input Output System. BIOS is actually firmware, the software that is programmed into a ROM (Read-Only Memory) chip built onto the motherboard of a computer. BIOS is what makes the system run an initial Power-On Self-Test of the computer, initialize circuits, load the boot program from the boot disk, and then handle low-level I/O to peripheral controllers such as keyboard and display.

AMI American Megatrends BIOS Beep Codes

  • 1 Long Beep – POST has passed all tests
  • 1 Beep – DRAM Refresh Failure. Try reseating the memory first. If the error still occurs, replace the memory with known good chips.
  • 2 Beeps – Parity Error in First 64K RAM. Try reseating the memory first. If the error still occurs, replace the memory with known good chips.
  • 3 Beeps – Base 64K RAM Failure. Try reseating the memory first. If the error still occurs, replace the memory with known good chips.
  • 4 Beeps – System Timer #1 Failure
  • 5 Beeps – Processor Failure
  • 6 Beeps – Keyboard Controller 8042 – Gate A20 Error. try reseating the keyboard controller chip. If the error still occurs, replace the keyboard chip. If the error persists, check parts of the system relating to the keyboard, e.g. try another keyboard, check to see if the system has a keyboard fuse.
  • 7 Beeps – Processor Virtual Mode Exception Interrupt Error
  • 8 Beeps – Display Memory Read/Write Test Failure (Non-fatal). Replace the video card or the memory on the video card.
  • 9 Beeps – ROM BIOS Checksum (32KB at F800:0) Failed. It is not likely that this error can be corrected by reseating the chips. Consult the motherboard supplier or an AMI product distributor for replacement part(s).
  • 10 Beeps – CMOS Shutdown Register Read/Write Error
  • 11 Beeps – Cache Memory error
  • 1 Long, 2 Short – An error was encountered in the video BIOS ROM, or a horizontal retrace failure has been encountered
  • 1 Long, 3 Short – Conventional/Extended memory failure
  • 1 Long, 8 Short – Display/Retrace test failed
  • 2 Short – POST Failure – One or more of the hardware tests has failed

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