The Manchester Mark I Computer, reconstructed image 2023
Guest post

A new view of the Manchester Computer

Seventy five years ago, the University’s ‘Baby’ computer became the first electronic computer with a read/write memory to run a program. To mark this historic event, Professor Jim Miles (University of Manchester Department of Computer Science) describes how a definitive new image of the Manchester computer was recreated using rediscovered original negatives.

A guest post by Professor Jim Miles, Department of Computer Science, The University of Manchester.

The “Baby” computer was developed at the University of Manchester by a team led by F.C. (Freddie) Williams and Tom Kilburn. It ran for the first time 75 years ago, on 21 June 1948 and became the world’s first electronic computer with a read/write memory to run a program.

The Baby occupied a room on the ground floor of the Electrotechnics building [now part of the Coupland Building, H24a] and its pioneering work is commemorated by a plaque on the external wall.

The Baby was an experimental machine that was continuously developed and extended by the Manchester team. There are no photographs of the machine as it was when the first program was run on 21 June 1948.

The machine (now known as the Mark I) was first fully photographed on 15 December 1948 by a technician, Alec Robinson, who used a 35mm Leica camera to photograph the machine in 20 sections – 4 rows of 5 photos from which a panorama of the whole machine could be built. Prints of these 20 photos were sent to the London Electrotype Company who used a physical cut and paste method to build a single collage, which was then photographed to form the panorama of the machine that was published in the Illustrated London News on 25 June 1949, and also in a Times article of 10 June 1949.

In early 2021, the University’s Department of Computer Science decided to replace all of its historical displays, including digitally replicating the panorama.  Over the following year Professor Jim Miles set about the task of tracking down the original photographic material. Incredibly, fourteen of the original negatives were uncovered, but one 35mm strip remains lost, probably forever. A rigorous process of document and correspondence tracing located one original print taken directly from the missing negatives and 4 negatives of photographs taken from original prints. Of one frame, the bottom right hand corner, no copy has been seen for over 50 years and the only available source is from copies of the original panorama photograph. 

Black and white image of the original Manchester Mark I computer
The ‘old’ view of the Manchester Mark I computer, 1948 [JRL16010271]

In March 2022 the best available source material for each of the 20 photos was assembled and imaged at high resolution by Jamie Robinson of the University Library’s Imaging team, who re-assembled the available parts of the panorama digitally. Steve McCabe, the University Estates Designer, then digitally recreated the missing corner of the panorama.

The result is a new, high resolution version of the panorama that reveals a wealth of detail about the machine that had previously been lost through repeated copying and poor quality printing processes. This has now become the University’s definitive photo of the Baby for use in all publicity material. The photos used to reconstruct the panorama have been added to the History of Computing Collection within Special Collections.

Black and white image of the Manchester Mark I computer
The ‘new’ view of the Manchester Mark I computer, 2023

On 21 June 2022, the Baby was recognised by the Institute of Electrical and Electronics Engineers (IEEE) as the first electronic computer with a random access read/write memory by their award of an IEEE Milestone. A plaque recording this award is mounted on the wall of the old Electrotechnics building in Coupland Street beneath the windows of the room in which the computer was located.

Replica version of the 'Baby' computer, Museum of Science and Industry, ManchesterMuseum
The replica ‘Baby’ computer, Museum of Science and Industry. Manchester (courtesy of the Museum of Science and Industry, Manchester)

By December 1948, when the panorama was photographed, the machine had roughly doubled in size from the original Baby computer. The racks of equipment down the left hand side of the room are an approximation of the Baby. In 1998, for the 50th anniversary, a fully operational replica of the Baby was built from original components by a team of Computer Conservation Society volunteers led by Chris Burton.

This replica is now located in the Science and Industry Museum, Manchester and is demonstrated weekly. The Science and Industry Museum will be celebrating the 75th anniversary on 21st June 2023 with a special exhibition and demonstration of the replica in operation.

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