We did it!

The rescue of the SDS 930 mainframe formerly at the Space Environment Center, Boulder, CO, USA, was accomplished with complete success on Wednesday, October 11, 1995, when CHAC took delivery of fourteen racks, two Teletypes, a console, a VDT, and approximately forty boxes of tapes, docs and spares, to a total of 10,300 pounds. Half a dozen CHAC stalwarts spent about two hours removing all ductape, non-historical stickers, deteriorated insulating foam, etc., and the whole computer is now in locked, ventilated steel container storage. As soon as possible we're going to have a Tiger Team Party to clean, dust, lubricate, and otherwise prepare for long-term storage with zero deterioration. Although the amazing thing is, how clean and pretty it is even now.... Deep thanks to thirty-four donors who contributed storage, logistical assistance, and over $7,000 in cash.

Many excellent photos were taken and Analytical Engine 3.2 leads off with a photo feature on the 930, its history, and its significance.

This is the console of the SDS 930. Click for a closer view (49K)

This fourteen-rack, four-ton mainframe is on permanent loan to CHAC from the Table Mountain Observatory of the Space Environment Center, United States Government. So far as we're concerned, this is the last known, complete, running, SDS computer in the world.

It was built by Scientific Data Systems in Santa Monica CA – Max Palevsky's company – and delivered to Table Mountain in 1963. After lengthy installation and configuration, it attained full duty cycle by 1965, and was then one of the fastest, gutsiest real-time scientific computer systems available. SDS' computers were good enough to worry DEC, which was a direct competitor and about to go public; good enough to worry the mighty IBM, which had just bet the company on the System/360. And the 930 was then the top of SDS' line, for which the Space Environment Laboratory forked over three hundred thousand dollars – the rough equivalent of US$1.2 million today.

Ah, but what they got for all that money. The 930 was supremely agile and versatile, programmed in bare-metal machine language for speed above all. It could take in or send out data while it was performing computations, or running diagnostics. Downtime was minimized with lavish redundancy, multiple power supplies, solid silver connectors, and fat heat sinks. From the first power-up, this was a racehorse, that could outrun its own seven-track tape drives and ended up with a fifty-megabyte stainless drum (I said fifty megabytes I said mid-sixties) for main storage. SEL set it to work at one of the most demanding tasks in computing — continuous real-time data acquisition, no rest for a machine that never wearied. From 1965 to 1970 the 930 served as the main computer for the government's HANDS (High Altitude Nuclear Detection System) early-warning program. Thereafter it acquired data from the GOES series satellites and many other spacecraft.

This is a computer justly famous on the strength of its accomplishments alone. But it's also (did we mention?) the last known, complete, running, XDS or SDS computer, in the world. Nor are we talking cold, hulking racks in a dim warehouse. The CHAC took over this computer in operating order, with cabling, schematics, full docs, bales of parts, and complete software on tape....still warm, so to speak. Built in Santa Monica and dedicated to longer service than was ever foreseen (even by SDS' own chief engineer!), the 930 will soon — we hope — find a proper home in California, where it can belong to scientists and engineers, historians, the American people, and posterity.

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