Digital Equipment Corporation PDP–7/A - S#104

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	S#104 in manufacture. ©2009 Computer History Museum Click image for a larger version

Massachusetts Institute of Technology, project MAC

The PDP–7 Service list (1972) shows that machine #104 was shipped to the Massachusetts Institute of Technology project MAC in January 1966 and consisted of the following options –

Option	S#	Ship	DEC #	Notes
149B	000055	0166	999999	4K memory upgrade to 8K
177B	000003		000048	Extended arithmetic element
637	000057	0766	042540	Bit synchronous data communication system
KA71	000002		000000	I/O device package
KA77	000002		000000	Processor unit

For descriptions of the above options see the full PDP–7 options list.

Digital Equipment Corporation PDP–7/A S#104 was installed at Massachusetts Institute of Technology and used in project MAC, now the Laboratory for Computer Science, where another milestone in the development of computers was developed - time–sharing. Founded in 1963 as Project MAC (Multiple Access Computer and Machine–Aided Cognition), the Laboratory developed the Compatible Time–Sharing System (CTSS) one of the first time shared systems in the world, and Multics - an improved time–shared system that introduced several new concepts. These two major developments stimulated research activities in the application of online computing to such diverse disciplines as Engineering, Architecture, Mathematics, Biology, Medicine, Library Science, and Management. See the Wikipedia page.

April 2023 – Lars Brinkhoff has emailed in to eleborate that he believes machine #104 is the one used on project MAC for the "KLUGE display", a DEC 340 graphics display module used to visualize, study and model the structure of proteins and nucleic acids. This provided and early 3D type display with a "globe" for manipulating the display's image. The PDP-7 mini-computer took over some of the computational tasks from an IBM 7904. See the following links - ResearchGate, and ACA History.

120 PDP–7 and PDP–7/A systems were forecast to be built in total, but the 1972 18–bit service list available (6.5Mb pdf download) only has details of the 99 known PDP–7 and PDP–7/A systems in the list at that time. We do not have any information about the possible remaining 21 systems, who they were delivered to or even if they actually existed.

The PDP–7 appeared to have sold well into Government research and University sectors with 11 systems shipped to the UK alone, almost 10% of the forecast production run! Serial numbers are concurrent for both PDP–7's and the PDP–7/A's, so the missing 21 could be of either type; however we are reasonably confident that the 99 systems shipped were the only ones that were ever built.

If you know of any information about any of the PDP–7 systems worldwide, options, location of existing systems, spare parts, ancillary bits, software, tapes or manuals, then please contact us.

Documents associated with PDP–7 S#104 - None at this time