Mainframe Computer Component, Magnetic Shift Register from the Mark IV Computer


This is a magnetic shift register which was part of the Harvard Mark IV computer. It is one of two hundred such registers used in the computer. The unit is mounted in a metal rack with a square cross-section. Four metal rods run end-to-end in the rack, holding the magnetic cores. Thirty-two cores are mounted on each of three of the rods; the fourth rod holds thirty-four. The cores are separated by individual holders fastened to the rod, as well as by insulators and magnetic isolators. they are also linked by rectifiers and resistors. Each core is about 5/8 inches in diameter, wound with multiple turns of fine copper wire. The end of the rack with a handle has sockets for four 6V6 vacuum tubes which would drive the unit - the tubes themselves are missing.

The Mark IV computer was, as the name suggests, the fourth in a series of computers built under the direction of Howard Aiken - the Mark I and Mark II were relay machines, while the Mark III had some electronic parts. The Mark IV was the first all-electronic machine in the series. Like the others, it was built at the Harvard Computation Laboratory - in this case the sponsor was the U.S. Air Force. The machine was built in 1951 and 1952 for use at Harvard. This component was one of two saved by the donor, Vincent E. Giuliano, when the machine was destroyed in 1958 or 1959, when he was a Harvard graduate student working on a doctorate at the Computation Lab.

Date Made: 1951-1952

Maker: Harvard University. Harvard Computation Laboratory

Location: Currently not on view

Place Made: United States: Massachusetts, Cambridge

See more items in: Medicine and Science: Computers


Exhibition Location:

Credit Line: Gift of Vincent E. Giuliano

Data Source: National Museum of American History

Id Number: 1987.0041.01Catalog Number: 1987.0041.01Accession Number: 1987.0041

Object Name: computer component, mainframemainframe computer component

Measurements: overall: 73.7 cm x 12.3 cm x 12.3 cm; 29 1/32 in x 4 27/32 in x 4 27/32 in


Record Id: nmah_1398075

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