Technical information

Appendix B. System Address Maps
Appendix B. System Address Maps
System Memory Map
Memory can be mapped differently if POST detects an error.
Table 50. System Memory Map
Address Range (hex) Size Description
00000000–0007FFFF 512 KB DOS applications
640 KB Memory gap
768 KB Video buffer
1 MB Expansion and BIOS region
15 MB Cacheable
16 MB Optional memory space gap
512 MB Always cacheable
FEC00000–FEC01000 4 KB I/O APIC default
FEE00000–FE010000 4 KB APIC default
FFF80000–FFFDF000 384 KB Extended BIOS
FFFE0000–FFFFFFFF 128 KB BIOS memory shadowed
42  Copyright IBM Corp. 1996, 1997