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143 Appx. D
D.2 1st MB memory map
D.3 DMA channel assignments
Table D.2: 1st MB memory map
Addr. range (Hex) Device
F0000h - FFFFFh System ROM
*CC000h - EFFFFh Unused (reserved for Ethernet ROM)
C0000h - CBFFFh Expansion ROM (for VGA BIOS)
B8000h - BFFFFh CGA/EGA/VGA text
B0000h - B7FFFh Unused
A0000h - AFFFFh EGA/VGA graphics
00000h - 9FFFFh Base memory
*
If Ethernet boot ROM is disabled (Ethernet ROM occupies about 16 KB)
* E0000 - EFFFF is reserved for BIOS POST
Table D.3: DMA channel assignments
Channel Function
0 Available
1 Available (audio)
2 Floppy disk (8-bit transfer)
3 Available (parallel port)
4 Cascade for DMA controller 1
5 Available
6 Available
7 Available
* Audio DMA select 1, 3, or 5
** Parallel port DMA select 1 (LPT2) or 3 (LPT1)