Mitsubishi Electric Apricot XEN pentium, Owner'S Handbook Manual

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A/10 XEN OWNER'S HANDBOOK
Inside your computer
Appendix A
Every address contains 8-bits of data, a byte. Each bit can be
thought of as a switch which can be either on or off. A byte is
like a bank of 8-switches, where each switch can be on or off.
ON
1 2 3 4 5 6 7 8 OFF
BYTE
ON
1 OFF
BIT
So 1Mbyte of memory consists of 1048576 (see Numbers and
computers) locations each containing one byte of data.
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 your
computer. Diagrams like these are called memory maps, and
are a convenient way of representing processor address space.
BIOS
RESERVED
EXPANSION CARD ROM
VIDEO BIOS
VIDEO MEMORY
DOS
1M-1
960K
896K
800K
768K
640K
FFFFFh
F0000h
E0000h
C8000h
C0000h
A0000h
00000h
0