Chapter 5 Device Mapping; Memory Map (Lpx/Lpx+) - DEC DECpc LPx Service Maintenance Manual

Digital DECpc LPx/LPx+
Chapter 5
This section provides a series of tables listing mapping and address information related to computer
memory and various main logic board devices (keyboard controller, interrupt controller, DMA controller,
etc.).
The computer's memory and address locations are allocated at the factory to operate within a standard PC
environment. However, due to the number of optional devices and/or expansion boards that are available,
sometimes memory and address locations need to be changed. For example, some network expansion
boards require a specific memory location. If that location is already allocated, a memory conflict results
and the expansion board will not operate as expected. Note that some memory, I/O and interrupt locations
can be changed using the BIOS Setup utility.
CAUTION
Before changing any memory or address location, refer to the documentation supplied
with the optional device, expansion board, or software application and make sure
adequate information is available.

Memory Map (LPx/LPx+)

NOTE
After the computer completes the POST, the E0000h address range is available for
EMS page frame.
Address Range
00000 to 9FFFF
A0000 to BFFFF
C0000 to C7FFF
C8000 to DFFFF
E0000 to FFFFF
100000 to 3FFFFFF
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Function
Base memory
Video RAM
VGA BIOS
BIOS extension ROM (AT bus
usage)
Computer BIOS
Extended memory
Device Mapping
Device Mapping
Notes
640 KB
128 KB
32 KB
96 KB
128 KB
63 MB
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