IBM PS/2 Model 30-286

In 1987 IBM had to offer something to compete with Apple's Macintosh computers. PS/2 line of PC computers was the "next step" of PCs. Models 25 and 30 had 8086 CPU and were highly improved, but still ISA-based PCs. Higher-end models, like Model 50 or 60 had MCA slot. Introduced in 1988, Model 30 286 is a major upgrade of Model 30. It has a faster, 10MHz 286 processor, 16-bit ISA slots and hard disk, which was repeatedly increased in new revisions, up to 40MB (marketed as 45MB, in fact 42MB) in 1991.
The hard disk, manufactored to order by Seagate (e.g. 42MB ST-157L), had a proprietary interface, a bit different than DBA (Direct Bus Attachment) present in other PS/2s, closer to ST506 and ESDI, but not compatible. Looking at schematic, we can see that there is more of XT IDE than ESDI in it and ST157 disk was primarily designed to be IDE.
Model 30-286 had a color VGA graphics chip, which made it able to display 640x480 in 16 colors.

Manufacturer IBM

Origin USA
Year of unit 1991?
Year of introduction 1988
Class PS/2
CPU Intel 286 + 287 math coprocessor
Speed 10MHz
RAM 1MB (2x256K 30-pin SIMMs, expandable to 4MB)
ROM PC BIOS, BASIC (boots if it can't boot form anything)
Graphics VGA
Sound PC Speaker
System expansion bus ISA
Floppy/removable media drives 1x 1.44MB 3.5" FDD (proprietary cable, the same as in some PS/1)  


Hard disk: 42MB ST-157L, proprietary connector)

Power supply:

Peripherals in collection:
 - None

Other cards:


Non-standard expansions: None
Operating system(s): IBM PC-DOS.

My unit comes from the lab, where it was used probably with some kind of spectrometer. The software was still there, along with few results, probably of some kind of fuel analysis (I'm not a chemist). It looks like the machine has been extensively used since 1991 till 2010, and hard disk is not in a good condition (few blocks at the end are slowly failing). The computer has NPU, probably to speed up information processing from spectrometer.

If you want to know, here is the mainboard description taken from IBM Hardware MAintenance Manual. RTC is a DS1287, which is battery-powered. If your DS1287 has weak battery, you can always rework it to use normal CR2032 battery.

Contents: Starting, usage Links


This computer is a normal PC, so it will start normally. Eventually it may jump to BASIC when it has no media to boot from. BASIC is in 128kB of its ROM. If any error is present, it will like most IBMs, display codes. See codes in IBM Codes page.

It is very important to park disk heads using tool e.g. supplied in setup disk before powering the system off, because early drives just leave heads where they were used and power is cut off. This condition may damage the disk.





Links:*IBM - Mainboard schematics! - Operations guide - Description - Disks and hardware manual for many PS/2 computers