Appendix 101
Memory map
Address
(Decimal)
Address
(Hexadecimal)
Size
Description
0-KB–640-KB
0000:0000–
0009:FFFF
640-KB
Main memory for
user applications.
640-KB–
768-KB
000A:0000–
000B:FFFF
128-KB
Video graphics
display buffer
768-KB–
896-KB
000C:0000–
000D:FFFF
128-KB
Reserved for ROM
on I/O adapters
896-KB–
1024-KB
(1-MB)
000E:0000–
000F:FFFF
128-KB
System BIOS ROM
Above 1-MB
1-MB–16-MB
0010:0000–
00FF:FFFF
15-MB
Extended Memory
15-MB–16-MB
00FE:0000–
00FF:FFFF
64-KB
Mapped RAM or
ROM
Above 16-MB
16MB–
1024-MB
(1-GB)
0100:0000–
3FFF:FFFF
1-GB
(minus
16-MB)
Total accessible
extended memory
above 16-MB
128-MB–
4084-MB
(4GB minus
2MB)
0800:0000–
FFFD:FFFF
3966-M
B
Mapped to ISA
slots
4-GB minus
64KB–4-GB
FFFF:0000–
FFFF:FFFF
64-KB
System BIOS ROM
4079tl.book Page 101 Tuesday, December 22, 1998 2:04 PM