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

0F0000h

0EFFFFh

0E0000h

0DFFFFh

0C0000h

0BFFFFh

0A0000h

09FFFFh

080000h

07FFFFh

000000h

System BIOS

Extended

System BIOS

Add-in Card BIOS and Buffer Area

PCI/ISA Video or SMM Area

ISA Window Area

DOS Area

1MB

960KB

896KB

768KB

640KB

512KB

0

=Shadowed in main memory

=Mappable to PCI or ISA memory

=Main memory only

=PCI only

Figure 15. DOS Compatibility Region

Revision 1.0

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C78844-002

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Intel SE7520JR2 manual DOS Compatibility Region Revision C78844-002