David Millsom

I was studying for a B.A. but after the first year, living in digs in Fitzroy with other students I didn’t get on particularly well with, I took to reading books I bought from Technical Book Shop (regrettably, no longer there). I was teaching myself computer languages and after I had written my first program, I scoured the campus for a computer on which to run it.

The only machine available was a PDP-9, owned by the Chemistry Department and used to control a gas-chromatograph. It was two metres wide and about 75cm deep. There was one manager, John Edwards, one secretary, Margo Huxley and a technician, Barry Pierce. It had 8K of 18-bit magnetic core memory, a paper tape reader/punch, and (in)famous DECtapes: tiny reels that spun back and forth. Programs were inputted from tape and the results printed on a teletype. Later, they were replaced by a card reader and a line printer.

I very quickly discovered that if I wanted to write and execute programs I would need to learn how to run the machine myself. I was allowed to do this after some instructions and trial and error. The computer was housed in a couple of rooms in the basement of the Thomas Cherry building where I spent a good part of the next two years of my Arts degree learning computer languages, Fortran, Algol, assembler, Snobol and Focal and, in fact, enough about computing to be admitted into the third year of a B.Sc at Monash, after I finished my B.A. I then proceeded to complete a B.Sc. at Monash.

La Trobe's first computer - Digital Equipment PDP-9 (8k memory)

La Trobe’s first computer – Digital Equipment PDP-9 (8k memory)

The machine moved around a few times to more spacious ground and 2nd floor digs. However, while it was still in the Thomas Cherry building, the basement flooded. I don’t know how deeply the PDP-9 was submerged in the muddy water but it was non-trivial. The recovery was novel. Barry, the technician, disassembled the machine into hundreds of component modules, each about the size of an iPhone 6. They were cleaned with alcohol and dried with a floor heater fan. After the modules were reinserted into the 9’s backplane, (oh horror!) there was still one module left over and, although Barry had the circuit diagrams, he could not find where it belonged. He finally decided that it must be left over or redundant. The machine was powered on and ran perfectly without it!

 

John Edwards in May 1971

John Edwards in May 1971

I will forever be grateful for the opportunity that small machine and the willingness of John Edwards to let me play with it, gave me. I have had a decent career in computers including 30 years in Silicon Valley, Cisco, and the Stanford Linear Accelerator. A career that began with the PDP-9!