BIOS

The base software, or BIOS, represents the program that is responsible for managing all the components installed in motherboard. In fact, the BIOS is an integral part of the motherboard and therefore can be attributed to a special category of computer components that occupy an intermediate position between hardware and software.

The base software, or BIOS, represents the program that is responsible for managing all the components installed in motherboard

The abbreviation BIOS stands for Basic Input / Output System - the basic input/output system. Previously, in the IBM PC system, the main purpose of the BIOS was to support I/O functions by providing an OS interface for interacting with hardware. Recently, its appointment and functions have significantly expanded.

The second important BIOS function is the POST (Power On Self Test) test of all hardware installed on the motherboard (with the exception of additional expansion cards), which takes place after each power-up of the computer. The testing procedure includes:

  • checking the health of the power management system
  • initialization of system resources and chip registers
  • Testing RAM
  • Connect keyboards;
  • Port testing
  • initializing controllers, defining and connecting hard drives.

During the initialization and testing of hardware, the BIOS compares the system configuration data with the information stored in the CMOS - special volatile memory located on the motherboard. Storage of data in the CMOS is supported by a special battery, and the information is updated whenever you change any BIOS settings. It is this memory that keeps the latest information about the system components, the current date and time, and the password for entering the BIOS or booting the operating system (if it is installed). If the battery is damaged, damaged or removed, all data in the CMOS memory is reset.

The third important function that the BIOS has been performing since the IBM PC era is the OS load. Modern BIOS allows you to boot the operating system not only from a floppy or hard disk, but also from drives CD-ROM, ZIP, LS-120, SCSI-controllers. Having determined the type of the boot device, the BIOS starts searching for the OS loader program on the media or forwards the download request to the BIOS of another device. When the response is received, the boot program is placed in the RAM, from which the system configuration is downloaded and device drivers of the operating system.

With the advent of Pentium processors, the BIOS began to perform another function - power management, and with the advent of ATX (Advanced Technology Extended) motherboard form factor motherboards - and the power-on and power-off function in accordance with the ACPI specification (Advanced Configuration and Power Interface - an advanced interface for configuration and power management).

There is also an Advanced Power Management (Advanced Power Management) specification. The difference between them is that the ACPI is performed mainly by means of the OS, and the workstation - by means of the BIOS.

Firms engaged in developing software for the BIOS, very little. Of the most famous, there are three: Award Software (Award BIOS), American Megatrends, Inc. (AMI BIOS) and Microid Research (MR BIOS). But on the vast majority of computers today are used different versions of the BIOS of the company Award Software. The user interface of different versions and different manufacturers of the BIOS can be very different, but system calls are strictly standardized.

Physically, the BIOS is in a non-volatile flash program flash memory, which is inserted into a special shoe on the motherboard (on this chip there is a bright holographic sticker with the logo of the firm - developer of the BIOS software).

Tools