addison@pollux.usc.edu (Richard Addison) (10/14/90)
My parents have an original model IBM PC that they are upgrading.
I'm helping them (2000 miles away) to do this without spending more
than they have to. We were fortunate enough to find the IBM ROM
BIOS upgrade so that they now have a harddisk on the system. What
remains is to fill out the rest of the 640K of ram.
As it stands now, they have 64K on the mother board and another
256K on an IDEAssociates combo card. This card was purchase back
in 1983 or 1984 (if I remember correctly). The dealer that is
doing the work for them (no labor charge, fortunately) has an
inexpensive "Memo" board that can hold 256K, 512K, or 768K. The
starting address for this board can be set to 64K, 128K, or 256K.
(There may be other settings, but it cannot be set to start at
320K according to the technician at the dealer).
What I'd like to do than is to set the IDEAssociates board (which
has a parallel port, an sockets for chips for a clock and a serial
port) to be only 64K of memory. Then we can use the "Memo" board
with 512K starting at 128K to get 640K. If we were to remove the
IDEAssociates combo card, we'd need to get a board with a parallel
port. This would cost more than what is necessary.
The problem is that we can't locate the information on the switch
settings for the IDEAssociates board!
Anyway, there are two DIP switches set thusly:
1 2 3 4 5 6 7 8 9
SW1: On On On Off On Off On Off Off
SW2: On Off Off Off Off On Off On Off
SW2 is closer to the parallel and serial port connectors, so I
beleive that it controls the addressing of the IO ports. SW2
probably controls the 4 banks of 9 64Kx1 dynamic RAM chips that
are on the front end of the board.
(Note: Although there are sockets for the optional chips, this
board does not have the serial port or clock.)
If any of you gracious people who've read this far happen to know
what the switch settings are for this IDEAssociates board, please
email the information. Alternatively, if you happen to know that
this "Memo" board (I'm not sure of the full name) that the dealer
is installing can be set to start at address 320K, let me know
that.
--Richard Addison