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4 Summary of the HP/Phoenix BIOS
BIOS Addresses
BIOS Addresses
This section provides a summary of the main features of the HP system
BIOS. This is software that provides an interface between the computer
hardware and the operating system.
System Memory Map
Reserved memory used by accessory boards must be located in the area
from C8000h to EFFFFh.
Product Identification
The reserved addresses in the 64 KB BIOS ROM data area, which contain
various product identification and BIOS identification strings, are no longer
accessed directly. Instead, the information is obtained from utilities in the
Desk Management Interface (DMI).
0 - 3FFh Interrupt vector table 640 KB: The addresses
0-9FFFFh are collectively
known as the Base
memory area
400h - 4FFh BIOS data area
500h - 9EFFFh
9F000h - 9FFFFh Extended BIOS data area
A0000h - BFFFFh 128 KB: Video memory area
C0000h - C7FFFh 32 KB: Video BIOS area
C8000h - D7FFFh 64 KB: available for accessory boards
(used by the boot ROM, if configured in the
Setup
program)
D8000h - EFFFFh 96 KB: available after the POST (for upper memory block, UMB, for example)
F0000h - FFFFFh 64 KB: System BIOS area
100000h - FFFFFFFFh 1 MB plus: Extended memory
