Memory Map - NEC VERSA SX User Manual

Memory Map

The system supports system and video shadowing, both controlled
through complementary metal oxide semiconductor (CMOS). The
system supports BIOS as a cacheable area with write protection. The
following table shows the system's memory map.
Memory Space
000000-0002FFh
000300-0003FFh
000400-0004FFh
000500-09FFFFh
0A0000-0AFFFFh
0B0000-0B7FFFh
0B8000-0BFFFFh
0C0000-0CBFFFh
0CC000-0CFFFFh
0D0000-0DFFFFh
0E0000-0EFFFFh
0F0000h-0FFFFFh
100000h-1FFFFFF
2000000-5FFFFFF
System Memory Map
Size Function
768 bytes BIOS Interrupt Vector Table
256 bytes BIOS Stack Area
256 bytes BIOS Data Area
639 KB Applications Memory (used by the
OS, device drivers, TSRs, and all
DOS applications
64 KB Video Buffer (EGA and VGA)
32 KB Video Buffer (monochrome, CGA
color, VGA monochrome)
32 KB Video Buffer (CGA, EGA color, and
VGA color)
48 KB Video ROM (EGA and VGA)
16 KB Unused. (Reserved for Adapter
ROMs and other devices requiring
ROMs)
64 KB Used by Adapter ROMs (i.e.,
network controllers, hard disk
controllers, SCSI host adapters)
64 KB Used by System ROM adapters (i.e.,
network controllers with boot
capability)
64 KB System AMIBIOS (includes Setup
and hard disk drive utilities)
32 MB Built-In Extended Memory
64 MB Extended Memory
Specifications B-9