IBM PC parts

From: Eric Smith <eric_at_brouhaha.com>
Date: Thu May 4 13:55:14 2000

Mike Ford <mikeford_at_socal.rr.com> asks:
> Was it really "later", or was the 64-256k an option available at the same
> time as the 16-64k?

It was really later. At FCS, 64K was the maximum supported on the planar.
IBM offered 64K expansion cards.

The PC required DIP switches on the planar to be set to indicate to the
BIOS the total amount of installed memory (both on the planar and
expansion cards). The maximum supported by the switch settings was well
under 640K. IBM-DOS believed the memory limit set by the BIOS, so if
you had more than the BIOS could understand, you had to use a batch
script with DEBUG, a TSR or other similar hack to make the machine
believe that it had more memory.
Received on Thu May 04 2000 - 13:55:14 BST