05/12/2021

020 – Minicomputing – 1960

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…we believed computers should be fun.  They were exciting.  They could do so many things.
The opportunities were just without bounds.  This was a great motivation in building a computer.  Ken Olsen

MIT’s Lincoln Laboratory managed the effort to transistorise the Whirlwind computer; the first outcome was the TX-0, transistorised experimental computer zero, pronounced ’ticks-oh’.

Operational by 1956, the TX-0 took up just a room whereas Whirlwind needed a full building. Wes Clark was the key logic designer, Ken Olsen the engineer and Ben Gurley designed its display.  In 1958 it was dismantled and moved to MIT where it took the operations manager John McKenzie a hundred days to reassemble and test it.

The first minicomputer was designed by Charles Molnar and Wes Clark.  This was the LINC, Laboratory Instrument Computer, designed for US National Institutes of Health to work with analogue inputs and outputs from a host of bio-med laboratory experiments.

This tabletop computer priced at c$43,000 was not inexpensive but compared with what else was available this was a very significant development.  The first LINC was available in early 1962 and some fifty were built, many by DEC as the subcontractor.  The LINC had been placed securely in the public domain by MIT but this was not to last.

Ken Olsen became disenchanted and quit before LINC’s completion.  He left the MIT team and with Charles Molnar and Harlan Anderson founded DEC, Digital Equipment Corporation, where they used the work on the TX and LINC to create a saleable product.

American Research and Development Corporation provided DEC with $70k venture capital funding –  for this investment it would later realise $450m!

Much of the early running in minicomputing was made by DEC.  Ben Gurley joined in 1957 and in just three and a half months laid down the design for its first computer, the PDP-1, Program-Data-Processor.

DEC appeared to deliberately choose a name that avoided the use of the ‘emotive’ term computer.  The PDP-1’s stated goals were simple – a fast and relatively inexpensive system.  At a price of over $100,000 with just 4,000 bytes of memory the word relatively sounds something of a stretch. 

From launch in November 1960 the PDP-1 was the first of the long-lived DEC PDP range of computers that moved the focus from mainframes towards the minicomputer. 

It sold only fifty PDP-1s but this set DEC on the way in evolving a market in mini-computing.  The prototype PDP-1 was donated to MIT where among other things Slug Russell would develop Spacewar!

Gordon Bell was recruited from the Speech Computation Laboratory at MIT to design the input/output for the PDP-1. 

In 1972 Bell described his ‘Law of Computer Classes’ that suggested the increase in capability and decrease in price would mean that, every decade, computing would evolve a new class of computer.  And this proved to be the case:

                •             mainframes in the ‘50s and ‘60s

                •             minicomputers in the ‘60s and ‘70s

                •             networked workstations/PCs in the ‘80s

                •             web-server browsing PCs in the early ‘90s

                •             portable hand-held computers in the mid ‘90s

                •             web services used via cellphone PCs in the 2000s

                •             2010s? this is forecast to be home and body networks.

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