User`s manual

DIGITAL-LOGIC AG MSLB-P5 Manual V0.3
PRELIMINARY 157
16 PROGRAMMER'S GUIDE
This chapter of the User's Manual gives application developers, programmers, and expert computer
users a detailed description of the BIOS.
This chapter describes the following subjects:
+ What is a ROM BIOS?
+ System Hardware Requirements
+ Fixed-Disk Tables
+ PhoenixBIOS Function Keys
+ POST Errors
+ Run-Time Services
What is a ROM BIOS?
This section briefly explains the function of a BIOS in managing the special features of
your system.
A ROM BIOS (Basic Input/Output System) is a set of programs permanently stored
in a ROM (Read-Only Memory) chip located on the computer motherboard. These
programs micro-manage the hardware devices installed on your computer. When you
turn on your computer, the ROM BIOS initializes and tests these devices. During run-
time, the ROM BIOS provides the Operating System and application programs with
access to these devices. You can also use the BIOS Setup program to change your
computer's hardware or behavior.
Software works best when it operates in layers, and the ROM BIOS is the bottom-
most software layer in the computer. It functions as the interface between the hard-
ware and the other layers of software, isolating them from the details of how the
hardware works. This arrangement enables you to change hardware devices without
having to install a new operating system.
The following diagram shows the function of the ROM BIOS as the interface between
the hardware and other layers of software:
Application Programs
Operating System and Device Drivers
ROM BIOS
System Hardware