Basic Input/Output System
basic input/output system
[′in‚put ′au̇t‚pu̇t ‚sis·təm]Basic Input/Output System
(operating system)In order to provide acceptable performance (e.g. for screendisplay), some software vendors access the routines in theBIOS directly, rather than using the higher level operatingsystem calls. Thus, the BIOS in the compatible computer mustbe 100% compatible with the IBM BIOS.
As if that wasn't bad enough, many application programsbypass even the BIOS and address the screen hardware directlyjust as the BIOS does. Consequently, register levelcompatibility is required in the compatible's displayelectronics, which means that it must provide the same storagelocations and identification as the original IBM hardware.