A Chronology of Digital Computing Machines (to 1952)

A Chronology...The Jargon FileComputer Dictionary
Jan 1948
Wallace Eckert (1902-1971, no relation to Presper Eckert and not mentioned again in this article) of IBM, with his team, completes the "SSEC" ("Selective Sequence Electronic Calculator"). This technological hybrid has vacuum tube logic with 8 20-digit registers, 150 20-digit words of relay memory, and a program that is partly stored but also controlled by a plugboard. IBM considers it the first computer.
Jun 1948
Max Newman, F. C. Williams, and their team at Manchester University, Manchester, England, complete a prototype machine called the "Mark I". This is the first machine that everyone would call a computer, because it's the first with a true stored-program capability. It uses a new type of memory invented by Williams, which uses the residual charges left on the screen of a CRT after the electron beam has been fired at it. (The bits are read by firing another beam through them and reading the voltage at an electrode beyond the screen.) This is a bit unreliable but is fast, relatively cheap, and much more compact (with room for about 1024 or 2048 bits per tube) than any other memory then existing.
The Mark I uses six of them, but I don't know of how many bits.
Its programs are initially entered in binary on a keyboard, and the output is read in binary from another CRT. Later Turing joins the team and devises a primitive form of assembly language, one of several developed in different places.
Newman was the first person shown Turing's 1937 paper in draft form.
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