The BIOS ("Basic Input / Output System" translate "elementary Management System I / O") is an essential component of the computer, allowing the control of the materials. This is a small software which a part is in ROM (read only memory, that is to say, a memory that can not be changed), and another part is in an EEPROM (changeable memory Pulse electric, hence the term flash to designate the action to change the EEPROM).
POST When the system is rebooted or undervoltage (Reset), the BIOS makes an inventory of the hardware in the computer and performs a test (called POST for "Power-On Self Test") to verify its functioning: Perform a test processor (CPU), check the BIOS, check the CMOS setup, Initialize timer (internal clock) Initialize the DMA controller, check the RAM and cache memory, install all features BIOS, verify all configurations (keyboard, floppy disks, hard disks ...)
If ever the POST encounters an error, it will try to continue booting the computer.
However, if the error is serious, the BIOS will halt the system: Display a message to the screen, if possible (the display hardware is not necessarily initialized yet or may be faulty), beep, as a sequence of beeps (beeps in English) to diagnose the cause of the fault, send a code (called POST code) to the serial port of the computer, which can be retrieved using a specific diagnostic equipment, If everything is correct, the BIOS generally emit a short beep, indicating that there are no errors. Want to know more about it? obtain "understand, Assemble and Repair your computer BC COMPUTERS.