Intel SE7525GP2 - Manual (Page 59)

Intel® Server Board SE7320SP2 & Intel Server Board SE7525GP2 TPS Functional Architecture
Revision 2.0 59
3.7.1.1 DOS Compatibility Region
The first region of memory below 1 MB was defined for early PCs, and must be maintained for
compatibility reasons. The region is divided into sub-regions as shown in the following figure.
Figure 10 - DOS Compatibility Region
3.7.1.1.1 DOS Area
The DOS region is 512 KB in the address range 0 to 07FFFFh. This region is fixed and all
accesses go to main memory.
3.7.1.1.2 ISA Window Memory
The ISA Window Memory is 128 KB between the address of 080000h to 09FFFFh. This area
can be mapped to the PCI bus or main memory.
= Mappable to PCI or ISA memory
= Main memory only
= PCI only
= Shadowed in main memory
000000h
07FFFFh
080000h
09FFFFh
0A0000h
0BFFFFh
0C0000h
0DFFFFh
0E0000h
0EFFFFh
0F0000h
0FFFFFh 1MB
960KB
896KB
768KB
640KB
512KB
0
System BIOS
Extended
System BIOS
Add-in Card BIOS
and Buffer Area
PCI/ISA Video or
SMM Area
ISA Window Area
DOS Area