/* C P / M B A S I C I / O S Y S T E M (B I O S) COPYRIGHT (C) GARY A. KILDALL JUNE, 1975 */ […] /* B A S I C D I S K … See more

The BIOS of the original IBM PC and XT had no interactive user interface. Error codes or messages were displayed on the screen, or coded series of sounds were generated to signal errors when the power-on self-test (POST) ha… See more

Early Intel processors started at physical address 000FFFF0h. Systems with later processors provide logic to start running the BIOS from the system ROM.
If the system has just been powered up or the reset b… See more

Peripheral cards such as hard disk drive host bus adapters and video cards have their own firmware, and BIOS extension option ROM may be a part of the expansion card firmware, which provide additional functionalit… See more

The BIOS ROM is customized to the particular manufacturer's hardware, allowing low-level services (such as reading a keystroke or writing a sector of data to diskette) to be provided in a standardized way to prog… See more

Historically, the BIOS in the IBM PC and XT had no built-in user interface. The BIOS versions in earlier PCs (XT-class) were not software configurable; instead, users set the options via DIP switches on the motherboar… See more

The original IBM PC BIOS (and cassette BASIC) was stored on mask-programmed read-only memory (ROM) chips in sockets on the motherboard. ROMs could be replaced, but not altered, by users. To allow for updates… See more