NASA Office of Logic Design

NASA Office of Logic Design

A scientific study of the problems of digital engineering for space flight systems,
with a view to their practical solution.

2006 MAPLD International Conference

Ronald Reagan Building and International Trade Center
with a session at the Smithsonian National Air and Space Museum

Washington, D.C.

September 26-28, 2006

"Redundancy in the Space Shuttle Avionics"

Hugh Blair-Smith
MIT Instrumentation Laboratory

Autobiography, November 2003

MAPLD 2006 Abstract: blair-smith_a.html

I was born in New York, but did not remain there long enough to become a Yankee fan, even for a minute. I grew up in Washington, Philadelphia, and Massachusetts; as a pre-teen I took up HO-gauge model railroading and cultivated a fascination with design. In my senior year at Harvard I discovered that computers were what I had been looking for the whole time. My first lessons in the subject were taught by Howard Aiken, so I can claim a sort of "apostolic succession" in the field.

More consequential was falling under the influence of Al Hopkins, Ray Alonso, and others that took the gospel according to Harvard down the river to MIT, but I didn't follow them deliberately. Instead, a moonlighting gig led to an offer from the head of the Digital Computing Group at MIT’s Instrumentation Lab, and I embarked on a 22-year career there, starting with an assignment to write a cross-assembler system for "an unknown number of computers with unknown characteristics," the so-called Mars computers under development by Eldon Hall, Al, Ray, etc. I quickly learned that the art of microprogramming they were developing for these power-frugal machines was even more fun than regular programming. Having spent much spare time in computer company showrooms scrounging programming manuals, I was positioned also to design instruction sets. These activities led to my proudest trophy, a Certificate of Commendation from MIT for "…contribution to computer design and programming for the Apollo Primary Guidance, Navigation and Control System."

Once the pressure of Apollo eased off, somebody advised me to get a life; being a tad inaccurate of hearing even then, I got married. I also got a sailboat, which has maintained my sanity (such as it is). My role in the Space Shuttle program centered around fault tolerance, especially the software-driven synchronization of the spacecraft’s General Purpose Computers. After that was mostly settled, I felt that the government was no longer interested in having a bunch of MIT "scientists" (a cuss word in the mouths of some ungrateful NASA types) push the envelope of computer design, so I plunged into the world of uncertain start-ups. I was on the founding group of Interactive Images (later Easel), and the same again of International Treasury Systems. When that collapsed, I became a migrant worker (software division), which included a brief reprise at what had become Easel before it too collapsed. I finally fetched up at Programart (now absorbed into Compuware), finding there another Apollo colleague, Bob Morse. I have been working both the PC and mainframe sides of this Performance Management house, having enough fun to ignore attaining the age at which a sensible person would have retired.

2006 MAPLD International Conference - Session G
"Digital Engineering and Computer Design: A Retrospective and Lessons Learned for Today's Engineers"

2006 MAPLD International Conference: Home Page

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