Head block from the Manchester Mark I drum store

• A block of 32 heads from the Manchester Mark I drum store photographed by Jim Miles on 4th July 2023. This head block is in the Department of Computer Science archives. A similar photograph of it is shown in F.C. Williams, T. Kilburn and G.E. Thomas, "Universal high-speed digital computers: a magnetic store", Proceedings of the IEE - Part II: Power Engineering, Vol. 99, pp94-106 (1952). Submitted for publication 30th April 1951. That paper describes the first of the Ferranti engineered drum stores used in the Manchester Mark I, the 2" high 11.5" diameter "wheel", and therefore that is the drum in which this head block was used. Two of these 32-track heads could be mounted in such a way that the tracks were interleaved on the drum surface, giving a maximum drum capacity of 64 x 2560 bits, or 20,480 bytes (4096 40-bit words).
  The heads on the Ferranti Mark I drum were mounted differently as can be seen in SET0016.

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ID: IMG5038. 4032x3024 (JPEG only). Copyright: unknown. Collection: Digital images from a variety of sources not part of the other collections. No source artefact.

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Edited 4-Mar-2026 (Jim Miles)

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