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basic input/output system (BIOS)

Basic Input/OutputSystem (BIOS) is a mini-operating system of personal computers, notebooks or other computers that contains the firmware and controls the input and output functions of the computer. The BIOS is written in a hardware-oriented programming language and is the actual interface between hardware and software.

The BIOS contains the basic hardware configurations at system startup and loads the operating system. When a computer is turned on, the operating system sends a request to the BIOS. The BIOS is initialized by booting, which performs the POST(Power On Self Test) self-test. Afterwards, the BIOS routines are processed and communication with the hardware components such as keyboard, mouse, drives, hard disk, RAMs and monitor is established.

BIOS Chip from ATMEL

BIOS Chip from ATMEL

The instruction set stored in the BIOS is written in the computer's machine language and is permanently stored in one or two chips, typically Programmable Read Only Memory (PROM), Erasable PRO M (EPROM) or Electrically Erasable PRO M (EEPROM). This has the advantage that when the personal computer (PC) is shipped, the BIOS is already hard-coded and always available and cannot be corrupted by hard disk errors. The BIOS also ensures that a personal computer can boot itself.

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Englisch: basic input/output system - BIOS
Updated at: 17.10.2013
#Words: 300