60
When installing expansion cards it is the first (bottom)
Mbyte of address space that is of most interest. The
following diagram shows how the bottom 1M of address
space is used in a XEN-LS II. Diagrams like these are
called memory maps, and are a convenient way of
representing processor address space.
BIOS
SETUP/OPTION ROM
EXPANSION CARD ROM
VIDEO BIOS
VIDEO MEMORY
DOS
1M-1
960K
896K
800K
768K
640K
FFFFFh
F0000h
E0000h
C8000h
C0000h
A0000h
00000h
0
Note
The top location of this first Mbyte is 1M-1 or FFFFFh. This
is because in the first Mbyte there are 1M locations,
starting at 0. Location 1M is the start of the second Mbyte
of address space.
The memory map above shows the uses of the first Mbyte
of address space. The memory map is arranged in this way
in order to be compatible with the ISA standard.