Logic door from Ferranti Mark 1* computer

1955 in Oldham
Logic door from Ferranti Mark I valve computer, c.1951.

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Logic door from Ferranti Mark I valve computer, c.1951.
Science Museum Group Collection
© The Board of Trustees of the Science Museum

Logic Door from the Ferranti Mark 1* computer used by Avro (A. V. Roe) aircraft manufacturers at their Chadderton factory from 1956-1966. This Ferranti Mark 1* was also manufactured in Chadderton, at Ferranti’s Gem Mill site.

In 1951 Ferranti began manufacturing Mark 1 computers, based on an improved design of the ‘Baby’ Computer (Small Scale Experimental Machine). They were the first computers in the world to be made for sale. Ferranti sold nine Mark 1 and Mark 1* computers to customers, including the University of Manchester, University of Toronto and the Italian government.

When they installed a Ferranti Mark 1* in 1956 at their Chadderton factory, Avro became the first British aerospace company to install a digital computer. It was used for their structural, aerodynamic and control calculations for the Vulcan Mark 2 delta wing bomber. It was also used for the design of the Hawker Siddeley 748 turboprop airliner.

Unlike the experimental ‘Baby’, the Ferranti Mark 1 computer was neatly engineered for sale. Complex components were built into logic doors, making the computer tidy and easy to repair. Avro’s Mark 1* was installed in a purpose-built room.


Computing & Data Processing
Object Number:
valves, transformers and metal (unknown)
Overall: 647 mm x 580 mm x 194 mm,
logic door