BIOS is the first program that runs after the computer or server is started. The BIOS is recorded on the motherboard chip and stored separately from the main hardware files. The BIOS performs the following important functions:
- Provides I/O operation.
- Manages component settings.
- Manages the further launch of all device systems.
- Conducts Power-On Self Test (POST) – any error that may be present in an element of a computing device will be detected at the initial stage.
There are only a few options for informing the user about the cause of the malfunction (the reason is the limited resources of the chip with BIOS). The most reliable notification option is sound notification. This method consists in determining the error in a particular element by tracking the number of signals and their duration. Next, we will consider the most popular types of sound encoding, since they differ between various motherboard providers.
AMI
| Type of sound signal | Description |
| 1 short |
No POST errors detected |
|
2 short |
RAM parity error |
|
3 short |
Problems in the first 64KB RAM |
|
4 short |
The system timer is not working correctly |
|
5 short |
CPU error |
|
6 short |
Incorrect operation of the input device controller |
|
7 short |
System board error |
|
8 short |
Incorrect operation of video memory |
|
9 short |
Incorrect BIOS checksum |
|
10 short |
CMOS memory write error |
|
11 short |
Cache memory error |
|
1 long, 2 short |
Problems with the video adapter |
|
1 long, 3 short |
|
|
2 long, 2 short |
Incorrect operation of the drive controller |
|
No signals |
Error in power supply or system board |
IBM
|
Type of sound signal |
Description |
|
Continuous |
Power supply failure |
|
Repetitive |
Power supply or motherboard error |
|
1 short |
No POST errors detected |
|
2 short |
Error when starting the video system |
|
1 short and blank screen |
The video adapter is not working correctly |
|
1 short, 1 long |
Motherboard error |
|
2 short, 1 long |
Mono/CGA malfunction |
|
3 short, 1 long |
EGA/VGA malfunction |
Award
|
Type of sound signal |
Description |
|
1 short |
No POST errors detected |
|
1 long, 2 short |
Video adapter error (you need to check if it is connected) |
|
1 long, 3 short |
Video adapter error or keyboard malfunction (depends on BIOS version) |
|
1 long, 9 short |
BIOS chip error (impossible to read the BIOS) |
|
1 long or repetitive |
RAM failure |
|
2 short |
Not a serious error (you can easily fix it in the BIOS settings) |
|
3 long |
Malfunction of the keyboard controller |
|
No signals |
Error in system board or power supply |
Compaq
|
Type of sound signal |
Description |
|
1 short |
No POST errors detected |
|
2 short |
Global system startup error |
|
1 long, 1 short |
CMOS BIOS memory checksum error |
|
1 long, 2 short |
Video adapter malfunction |
|
1 short, 2 long |
RAM operation error |
|
7 repetitive signals |
AGP fault |
|
Continuous |
Malfunction of RAM |
Troubleshooting during system boot
If you receive a sound notification about an error, you can try to restore the system boot. First, it is recommended to check the connection of the device element that caused the system to malfunction.
Another reason for the failure may be incorrect BIOS settings. This error can be resolved by performing a factory reset. The BIOS control panel menu should contain the Load Default Settings function. Factory reset can be performed using this function.
By disconnecting the BIOS battery for 15 minutes, you can reset the parameters. It is useful, if the device still does not turn on, and it is not possible to perform a software setup.
Usually minor faults can be eliminated by rebooting the system. Anyway, there are various methods of solving the problem under consideration:
- connecting a missing element,
- replacing a controller,
- formatting data, etc.
