DigiBarn Systems: The IBM PC/AT

The IBM PC/AT (model number 5170)

The IBM PC/AT (for "Advanced Technology") was introduced in mid 1984 and was IBM's beefier business machine. Riding on the tremendous succes of the original IBM PC the AT moved into the higher powered 6MHz 286 Intel processor and supported an internal hard disk (although did not ship with one standard). Your curator, Bruce Damer, worked as a student at the IBM Toronto Development Lab in the May-August 1984 time frame and remembers seeing the AT before its release. In place of the silver label you see on production ATs, was a code-name label sporting tiny pyramids. The AT was code-named "big top" internally and the pyramids resembled circus tents. With the PC, XT and now AT I guess IBM now had a true "three ring circus" going. Oh I forgot the PC Jr (which was code named "peanut").

One other thing I recall is that if you had to transport the pre-launch AT around IBM and had to take it out in public or on a flight, you had a special box, with all kinds of odd shapes attached, that would foil the attempts of any spies (or industry media) even guessing the dimensions of the new computer. IBM was sure careful in those days and projects really were carried out in secret. I doubt whether "today's IBM", Dell, has such measures in place. New systems like the AT did not come around as frequently as models are cranked out today by the volumen manufacturers. Now on to more about the AT...

Sitka Alaska attorney Denton Pearson made this kind donation of this wonderful early production IBM AT. He also donated two IBM PC 5155 transportables. Hear Denton describing this system at this page at DigiBarn Radio. Thanks Denton!!!

The IBM PC/AT 5170	This unit had two floppies, no hard disk, Denton moved one floppy to his 5155 portables	DSC03143.JPG
DSC03144.JPG	DSC03145.JPG	DSC03146.JPG
DSC03147.JPG	DSC03148.JPG	Hard disk expansion cabinet from IBM 5155 transportable

IBM added a lot of new features: they abandoned the old Intel 8086 to the Intel 80286, so the PC AT used new 16 bit expansion slots.

The PC AT had a new version of the Microsoft OS: MS-DOS 3.0 which could manage the new 5.25" floppy disk format (1.2 MB), the new hard disk capacities (20 MB and more) and allowed file sharing. It had a new keyboard too (the same we use now, more or less) with cursor keys and a key that could lock it.

Two models were launched: the PC-AT model 1 (256 KB RAM, two floppy disk units and a color screen) and the PC-AT Model 2 (512 KB RAM, one floppy disk unit, one hard disk and a color screen).

This computer was revolutionary, but it was the last time IBM imposed a standard to the PC clone industry. The next year, the first PC based on a 80386 was made by Compaq and IBM failed to impose the PS/2 standard in 1986.

See Also:

Our IBM PC 5155 transportables from Denton and original IBM PC and PC Jr.

Our interviews with Denton Pearson on DigiBarn Radio

Know anything more about this system? Contact us!

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