So what is the Computer POST?
The computer POST (Power On Self Test) which tests the computer insuring that it meets the necessary system requirements before booting up. If the computer fails the POST the computer then returns a beep code indicating what is causing the computer not to post the POST. Generally if the computer POSTs properly you will receive a single beep (with some computer BIOS manufacturers it may beep twice).
The POST Test
Each time the computer boots up the computer must past the POST. The following is the procedure of the POST:
1. The first step of POST is the testing of the Power Supply to ensure that it is turned on and that it releases its reset signal.
2. CPU must exit the reset status mode and thereafter be able to execute instructions.
3. BIOS must be have readable.
4. BIOS checksum must be valid, meaning that it must be readable.
5. CMOS be accessible for reading.
6. CMOS checksum must be valid, meaning that it must be readable.
7. CPU must be able to read all forms of memory such as the memory controller, memory bus, and memory module.
8. The first 64KB of memory must be operational and have the capability to be read and written to and from, and capable of containing the POST code.
9. I/O bus / controller must be accessible.
10. I/O bus must be able to write / read from the video subsystem and be able to read all video RAM..
--If the computer does not pass any of the above tests your computer will receive an irregular POST. An irregular POST is a beep code which is different from the standard which can be either no beeps at all or a combination of different beeps indicating what is causing the computer not to past the POST.
The following are Beep Codes that can occur. Because of the wide variety of different computer manufacturers, beep codes may vary.
AMI BIOS Beep Codes
1 short | DRAM refresh failure
2 short | Parity circuit failure
3 short | Base 64K RAM failure
4 short | System timer failure
5 short | Process failure
6 short | Keyboard controller Gate A20 error
7 short | Virtual mode exception error
8 short | Display memory Read/Write test failure
9 short | ROM BIOS checksum failure
10 short | CMOS shutdown Read/Write error
11 short | Cache Memory error
1 long, 3 short | Conventional/Extended memory failure
1 long, 8 short | Display/Retrace test failed
Award BIOS Beep Codes
1 long, 2 short | | Indicates a video error has occurred and the BIOS cannot initialize the video screen to display any additional information
Any other beep(s) | | RAM problem.
IBM BIOS Beep Codes
No Beeps | No Power, Loose Card, or Short.
1 Short Beep | Normal POST, computer is ok.
2 Short Beep | POST error, review screen for error code.
Continuous Beep | No Power, Loose Card, or Short.
Repeating Short Beep | No Power, Loose Card, or Short.
One Long and one Short Beep | Motherboard issue.
One Long and Two short Beeps | Video (Mono/CGA Display Circuitry) issue.
One Long and Three Short Beeps. | Video (EGA) Display Circuitry.
Three Long Beeps | Keyboard / Keyboard card error.
One Beep, Blank or Incorrect Display | Video Display Circuitry.
Note: Not all computers have beep codes, some of the newer computers have LED's that light up that indicate the error or have a sound file to indicate the error.
Source: xboard.us
The computer POST (Power On Self Test) which tests the computer insuring that it meets the necessary system requirements before booting up. If the computer fails the POST the computer then returns a beep code indicating what is causing the computer not to post the POST. Generally if the computer POSTs properly you will receive a single beep (with some computer BIOS manufacturers it may beep twice).
The POST Test
Each time the computer boots up the computer must past the POST. The following is the procedure of the POST:
1. The first step of POST is the testing of the Power Supply to ensure that it is turned on and that it releases its reset signal.
2. CPU must exit the reset status mode and thereafter be able to execute instructions.
3. BIOS must be have readable.
4. BIOS checksum must be valid, meaning that it must be readable.
5. CMOS be accessible for reading.
6. CMOS checksum must be valid, meaning that it must be readable.
7. CPU must be able to read all forms of memory such as the memory controller, memory bus, and memory module.
8. The first 64KB of memory must be operational and have the capability to be read and written to and from, and capable of containing the POST code.
9. I/O bus / controller must be accessible.
10. I/O bus must be able to write / read from the video subsystem and be able to read all video RAM..
--If the computer does not pass any of the above tests your computer will receive an irregular POST. An irregular POST is a beep code which is different from the standard which can be either no beeps at all or a combination of different beeps indicating what is causing the computer not to past the POST.
The following are Beep Codes that can occur. Because of the wide variety of different computer manufacturers, beep codes may vary.
AMI BIOS Beep Codes
1 short | DRAM refresh failure
2 short | Parity circuit failure
3 short | Base 64K RAM failure
4 short | System timer failure
5 short | Process failure
6 short | Keyboard controller Gate A20 error
7 short | Virtual mode exception error
8 short | Display memory Read/Write test failure
9 short | ROM BIOS checksum failure
10 short | CMOS shutdown Read/Write error
11 short | Cache Memory error
1 long, 3 short | Conventional/Extended memory failure
1 long, 8 short | Display/Retrace test failed
Award BIOS Beep Codes
1 long, 2 short | | Indicates a video error has occurred and the BIOS cannot initialize the video screen to display any additional information
Any other beep(s) | | RAM problem.
IBM BIOS Beep Codes
No Beeps | No Power, Loose Card, or Short.
1 Short Beep | Normal POST, computer is ok.
2 Short Beep | POST error, review screen for error code.
Continuous Beep | No Power, Loose Card, or Short.
Repeating Short Beep | No Power, Loose Card, or Short.
One Long and one Short Beep | Motherboard issue.
One Long and Two short Beeps | Video (Mono/CGA Display Circuitry) issue.
One Long and Three Short Beeps. | Video (EGA) Display Circuitry.
Three Long Beeps | Keyboard / Keyboard card error.
One Beep, Blank or Incorrect Display | Video Display Circuitry.
Note: Not all computers have beep codes, some of the newer computers have LED's that light up that indicate the error or have a sound file to indicate the error.
Source: xboard.us
No comments:
Post a Comment