Artifact Details


LLNL S1 Mark IIA supercomputer

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Still Image


8 x 10 in.


LLNL S1 Project supervisor Dr. Lowell Wood writes:

"The person standing next to the S-1 Project’s Mark IIA supercomputer – only part of one side of whose cabinet is shown in this photo -- is the late A. Carl Haussmann, then Lawrence Livermore National Laboratory’s Associate Director-at-Large (and its one-time Acting Director).

The S-1 Project was the Lab’s one-&-only “roll your own” supercomputer endeavor. It was led by me with Tom McWilliams and Curt Widdoes in 1975, and which was joined the following year by Mike Farmwald – graduate students of Forest Baskett’s in Stanford’s Computer Science Department, each of whom wrote his Ph.D. dissertation on different aspects of their S-1 Project efforts. They first designed-&-built the S-1 Mark I supercomputer and then used it in a classic “bootstrap” process to host their SCALD (Structured Computer-Aided Logic Design) software system to design-&-build the follow-on Mark IIA.

The Mark IIA was a capability-demonstration system which ran a variety of US Government applications software, and briefly was a nodal machine on ARPANET and MILNET, via the S1 IMP (Interface Message Processor). Among its specialty features was the performance-as-single-instruction of a large set of mathematical functions, including FFTs – a remarkable set of capabilities which Mike Farmwald designed-&-built into it for his Ph.D. dissertation topic. It was able to run programs which made intensive use of these functions faster than the same programs running on the Cray-1, which was then the fastest commercially-sourced supercomputer. It also had a billion-bit semiconductor RAM memory, which was then the most capacious in the world by a substantial factor."



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