Summary of IBM PS/2 model 70

This is a high-level summary of general characteristics of the machine. For details (which are of course subject to change) the machine itself, and the manuals concerning it, must be consulted.

This machine was for a few months the most powerful at the Center, somewhat improving on the PS/2 model 80 which had been the largest for some years. It is somewhat compromised, though, by the limited number of option card slots imposed by its non-tower design. However, once its failed network card has been dealt with (see below) it should be one of the Center's prime development machines.

Note it has been supplanted as the prime machine by 2 486-based PC's (not PS/2's) from EduQuest (IBM).

Owner, if known:

UC Irvine.

CPU:

20MHz 80386

Operating system:

PC-DOS 3.3, 128K BIOS

Bus architecture:

MicroChannel

Physical memory:

1024K conventional + 1024K extended
(-64K for 128K BIOS)
Has been extended to 6MB physical; however, at some point during the installation of new memory, the WD8003E/A network card appears to have suffered damage. Its presence in the machine now prevents the machine from even moving through its power-up tests: all progress halts before anything even appears on the screen.

"High" ("adapter", trans-640K) memory usage:

EMS page frame buffer
WD8003E/A shared RAM

Memory management:

Have tried 2 major schemes to free enough memory for compiling with Turbo Pascal:

• Quarterdeck QEMM
• Qualitas' 386 to the Max

At the times these were tried, QEMM seemed to yield the more stable configuration. Neither, at the time was compatible with Windows 3.1 . This prevented Windows from even starting up. Later versions, conforming to the DCPI (the DOS Control Program Interface) for coordinating 386-based protected mode usage, would probably have fared better with Windows.

Qualitas' BlueMax should also have been attempted, but was not available.

It was hoped these schemes would free enough memory for Turbo Pascal 6 to compile programs using Ports, which is very demanding of compile- time memory.

Local storage:

120MB ESDI hard disc (much quieter than the model 80's)
C: (32MB)
D: (32MB)
E: (32MB)
F: (24MB)

Important local Software or Data:

Turbo Pascal 6, DOS dialogue library development and release.

Graphics adapter:

IBM VGA, no enhancements.

Network:

PC-NFS on the WD8003E/A Note that the WD8003E/A is not the same model as the WD8003E.
NOTE: this arrangement has not be un-installed since the failure of the network card, mentioned above; but it is de-activated.

Remote drives (by network):

Until working network card can be safely installed: no remote drives.
M: and N: are configure to be available.

Special notes:

The righthand of the 2 floppy drives is B: . Its housing releases with 2 screws on the rear; the cover is then pulled forward and rotated up.

Because of the close-fitting assembly inside, it is often necessary to disassemble a lot of the machine, when doing upgrade or maintenance work, to reach the desired components. Also note there are very few adapter card slots, and one is already taken with the VGA board, and a second with the M-Motion board.

The power-up tests actually show the shortage of 64K of memory that the 128K BIOS takes from the rest of the system. This does not, as far as we know, indicate any problem with the system.

Running Windows 3.1, then exiting it, has been causing complete system freezes, requiring cold boot. There has been some suggestion this is related to the memory management software, and perhaps to the network packet drivers. This problem may have been solved with the extension of memory to 6MB, but this is not certain.

In order to be certain of the correctness of doing so, no update to PC-DOS 5 or MS-DOS 5 has been attempted on this machine until other, less essential PS/2's have demonstrated it can be done safely. (It is in any case increasingly likely a proprietary IBM PC-DOS 6.x would be required).