Intel® Server Board SE7520JR2

Functional Architecture

3.5.1.1DOS 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.

0FFFFFh

System BIOS

1MB

 

 

 

 

 

 

0F0000h

 

 

 

 

0EFFFFh

 

960KB

 

 

Extended

 

 

 

 

 

 

 

System BIOS

 

 

 

0E0000h

 

 

 

 

0DFFFFh

 

896KB

 

 

Add-in Card BIOS and

 

 

 

 

 

 

 

Buffer Area

 

 

 

0C0000h

 

 

 

 

0BFFFFh

 

768KB

 

 

PCI/ISA Video or SMM

 

 

 

 

 

 

 

Area

 

 

 

0A0000h

 

 

 

 

09FFFFh

 

640KB

 

 

ISA Window Area

 

 

 

 

 

 

080000h

 

512KB

 

= Shadowed in main memory

07FFFFh

 

 

 

 

 

 

 

DOS Area

 

 

= Mappable to PCI or ISA memory

 

 

 

 

 

 

 

 

 

0

 

= Main memory only

 

 

 

000000h

 

 

= PCI only

 

 

 

 

 

 

 

 

 

 

 

 

Figure 15. DOS Compatibility Region

Revision 1.0

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