Mitsubishi Electric Apricot XEN pentium, Owner'S Handbook Manual, Page: 128 / 147

A/12 XEN OWNER'S HANDBOOK
Inside your computer
Appendix A
The region from C8000h to DFFFFh is available for expansion
card ROM other than video BIOS. It is recommended that you
configure expansion card ROM at the bottom of this region,
with the address ranges as close together as possible without
any overlapping.
This will leave the maximum amount of memory free for use
as UMB space. For information on UMB space refer to your
DOS documentation, and the help files supplied with your
computer.
I/O ports
I/O ports are used by the processor to control the operation
of peripherals. Some expansion cards are controlled via an I/O
port or group of ports.
Which port or ports the card uses can normally be selected
on the card. The following table lists the I/O ports used by
the motherboard. Any ports not listed below may be used by
an expansion card. Refer to the table, and the documentation
supplied with the card to establish which ports, if any, to use
and how to select them.