Intel SE7520JR2 Technical Manual page 72

Functional Architecture
3.5.1.1.1 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.
3.5.1.1.2 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.
3.5.1.1.3 Video or SMM Memory
The 128 KB Graphics Adapter Memory region at 0A0000h to 0BFFFFh is normally mapped to
the VGA controller on the PCI bus. This region is also the default region for SMM space.
3.5.1.1.4 Add-in Card BIOS and Buffer Area
The 128 KB region between addresses 0C0000h to 0DFFFFh is divided into eight segments of
16 KB segments mapped to ISA memory space, each with programmable attributes, for
expansion cards buffers. Historically, the 32 KB region from 0C0000h to 0C7FFFh has
contained the video BIOS location on the video card
3.5.1.1.5 Extended System BIOS
This 64 KB region from 0E0000h to 0EFFFFh is divided into four blocks of 16 KB each, and may
be mapped with programmable attributes to map to either main memory or to the PCI bus.
Typically this area is used for RAM or ROM. This region can also be used extended SMM
space.
3.5.1.1.6 System BIOS
The 64 KB region from 0F0000h to 0FFFFFh is treated as a single block. By default, this area is
normally read/write disabled with accesses forwarded to the PCI bus. Through manipulation of
read/write attributes, this region can be shadowed into main memory.
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C78844-002
Intel® Server Board SE7520JR2
Revision 1.0