System Specifications (continued)

General system specifications

Video memory

System interrupts

System I-O

System memory

System DMA

 

 

 

System Memory
Size	Memory Address	System Function
640 K	00000000 - 0009FFFF	Base Memory
128 K	000A0000 - 000BFFFF	Video RAM
32 K	000C0000 - 000C7FFF	Video ROM
32 K	000C8000 - 000CFFFF	Legacy USB Device Header (when legacy support enabled)
64 K	000D000 - 000DFFFF	Unused
48 K	000E0000 - 000EBFFF	Unused (Not available for option cards. May use for UMBs.)
16 K	000EC000 - 000EFFFF	16-bit cacheable, shadowable, read-only memory. Not available for option cards.
64 K	000F0000 - 000FFFFF	System BIOS ROM shadow image
15 M	00100000 - 00FFFFFF	Standard Extended Memory
64 M	01000000 - 04FFFFFF	Rest of Extended Memory
60 M	05000000 - 07FFFFFF	Unused
512 K	08000000 - 0807FFFF	Standard Direct Video Memory
512 K	08080000 - 080FFFFF	Optional Direct Video Memory
1919 M	08100000 - 7FFFFFFF	Unused
16 M	80000000 - 80FFFFFF	Memory mapped I/O devices
~2000 M	81000000 - FDFDFFFF	Unused/System ROM aliases
128 K	FDFE0000 - FDFFFFFF	System ROM (alias)
~32 M	FE000000 - FFFDFFFF	Unused
128 K	FFFE0000 - FFFFFFFF	System BIOS ROM

 

 

 

System DMA
Hardware	System Function (Default)	Alternate Mappings
DMA 0	ECP Parallel	1, 2, none
DMA 1	Entertainment Audio	0, 3, none
DMA 2	Diskette Drive	none
DMA 3	Entertainment Audio	0, 1, none
DMA 4	Internally used for cascading
DMA 5	Available
DMA 6	Available
DMA 7	Available