Ferranti Mark I: drum store prototype

Magnetic drum for Ferranti Mark I. Picture of drum. (Catalogue 1).

• This image is shown in G.E. (Tommy) Thomas's recollections of the Manchester drum store, in which he describes it as an "experimental stage" of the drum store developed by Ferranti for the Ferranti Mark I computer.
  
• Images of the production drum store for the Ferranti Mark I computer are shown in SET0016 and setG829.
  
• The dismantled production drum in SET0016 shows the main frame containing the drum in the top right, the production frame differs from the experimental system at the top, the production frame not having the raised pyramidal section of the casting.
  
• This image was included as Figure 6 in a talk and paper given by Williams and Kilburn in 1951 with the caption "Testing magnetic drum". setG829 is also shown as Figure 7 "Magnetic drum installed" which shows a drum in the Ferranti Mark I computer. The description in the text is preceded by "These items were all, of course, included in some form in the final experimental machine, and in describing the present machine it will only be necessary to mention improvements and modifications." The drum shown here was therefore a Manchester Mark I (the "experimental machine") and a slightly modified form shown in SET0016 and setG829 was included in the Ferranti Mark I.
  (Williams, F.C. and Kilburn, T. (talk given by T. Kilburn), "The University of Manchester Computing Machine", Review of Electronic Digital Computers - Joint AIEE-IRE Computer Conference, Philadelphia PA, p.57-61, Conference dates December 10-12 1951, publication date 10 December 1951).
  
• The image shows a pre-decimal halfpenny dated 1949, possibly for scale. A halfpenny was 25.48 mm diameter. It is also possible that the halfpenny may have been to demonstrate the smoothness of the drum when running.
  
• A wider view showing surroundings and some of the electronic system is shown in plate S312. The location is not in the University and so is likely to be Ferranti labs. This image is not a cropped version of plate S312 because the hafpenny is missing.
  
• Comment from Simon Lavington (email to Jim Miles 30/07/2025):
  This picture was possibly taken in the Tin Hut at Moston. The Tin Hut had two large rooms, one of which was an open-plan area for Ferranti's programmers. The other large room was for engineering prototyping etc. In between these two large rooms were four offices. All this lot was front-ended by an entrance foyer and toilets. The Tin Hut was a post-war prefabricated structure which included aluminium panels. It was possibly designed to be used as a small (two-class) primary school.
  
• Image 'P4053J6-HJK6-1F' is an instance of this image. It is a scan of one of a set of Tom Kilburn's photographs: 22 Photographs of Mark I Ferranti. The set includes: 3 photographs marked on back "Mark I Machine 1951 - Copy made January 1968. Plus 2 other smaller copies. 4 photographs taken by Rex Lowden, Stoneheads, Whaley Bridge, Stockport. With reference numbers. 1 photograph -MS. Services Ltd., Ashton-u-Lyne (Photographers). Mostly different photos, 5 photos same. (From Hilary Kahn's documentation catalogue (c2006))
  The collection of prints is in Hilary Kahn's original Departmental archive, Location: Kilburn Room 2.53, filing cabinet A, drawer A4, blue folder HJK6. Wallet notes: On reverse: G876

---

This is the best of set $set22, which contains images P2117A, P4053J6-HJK6-1F, P4319J6-HJK22-29A, page107d and plate S311. ID: P4053J6-HJK6-1F. 7232x9566 (+TIFF) . Copyright: unknown. Collection: Scans of prints in Hilary Kahn’s original Departmental archive. Source artefact: P4053J6-HJK6-1F, 8" x 6" photographic print, condition: Very good. Artefact notes: On reverse: G876.

---

Set edited 4-Mar-2026 (Jim Miles)

---