Today marks the 75th anniversary of the arrival of the Ferranti Mark I computer at the University of Manchester. It was the first commercial digital computer to be delivered to a customer.
The Ferranti computer replaced the (Manchester) Mark I computer, which itself had evolved from the Small-Scale Experimental Machine or ‘Baby’, the machine which had run the world’s first stored computer program in 1948. The Ferranti Mark I proved critically important in ensuring the University remained a national centre for computing.
The University had worked closely with Ferranti, a local electrical engineering firm, to develop a commercial computer. Political and financial support was provided by a government agency, the National Research Development Corporation. Ferranti sold two Mark I computers and seven of the enhanced Mark I*. The University’s relationship with Ferranti continued, most notably with the ATLAS, a much more powerful computer than the Mark I, which was launched in 1962 .
The Ferranti machine was assembled at the Ferranti factory at Moston, and following delivery to the University went through months of testing, before it was formally launched at a conference on 9 July 1951. The computer was housed in a specially-built building on Coupland Street (now known as Coupland 1), adjoining the Physics and Electrical Engineering buildings. This was arguably the first building to be designed to house a digital computer, and included some special features such as electro-magnetic sheathing. In 1954, the computer was moved to the new Electrical Engineering (Zochonis) Building in Brunswick St, where it remained until decommissioned in 1958.
The new computer was more powerful than the earlier research machine. Housed in sleek metal cabinets, it looked more sophisticated than its predecessor. Ferranti claimed it contained “about 400 valves, 2500 capacitors, 15,000 resistors, 100,000 soldered joints and six miles of wire”. The computer’s magnetic drum provided eight times the storage of the original Manchester computer, consumed 27kw of power and was ventilated by a recirculating air system.
Day-to-day operation of the computer was the responsibility of the Computing Machine Laboratory, headed by Alan Turing, with Tony Brooker and Cicely Popplewell as his assistants.
The Ferranti computer was prone to running problems and ‘bugs’. The log books include frequent references to breakdowns, although as this log entry shows, sometimes it worked “beautifully”.
Vivian Bowden, then Ferranti’s computer “salesman”, and later the highly influential Principal of UMIST, wrote a scathing report about the Manchester machine in January 1953. Bowden called the maintenance of the machine “deplorable”, with its stores prone to “clodding”. The poorly designed time base and associated electronic equipment meant it was difficult to run even short programs without errors. He concluded that it was currently “vastly inferior to the ACE and the EDSAC” [the other major UK machines] (Bowden papers, BVB/1/166).
Bowden’s negativity might have reflected his frustrations in finding new customers for the computer, and on the credit side the Manchester machine did attract an extensive and largely appreciative group of users. As the Ferranti’s computing power was in excess of the University’s needs, computing time was provided to outside users for a fee.
These users included the Armaments Research and Development Establishment for ballistics calculations (this work was secret), R. K. Livesey’s work on rigid steel structures (possibly the first time a digital computer was used for a specific civil engineering project – a power station), and computational chemistry (Fourier analysis) by the Leeds University crystallographic research group. We are fortunate to have a paper tape program used by the Leeds team within our collections; these tapes are very rare survivals.
Alan Turing used the Ferranti for his own research work on chemical morphogenesis, usually working at night. Ferranti’s own engineers, led by Dietrich Prinz, were also frequent users, as they refined the programming capabilities of the machine (the company did not have its own computer).
The machine was used to develop computer games, a particular interest of Turing’s. His collaborator, Christopher Strachey, created a program for the game of draughts, and the machine could solve some specific chess problems. More usually, a game of pentominoes [a forerunner of Tetris] was demonstrated to visitors.
Strachey was responsible for more whimsical uses of the computer. He used its random number generator to create the so-called ‘love letters’, using pre-set syntactical patterns and words to generate quirky romantic missives. Strachey also manipulated the machine’s loudspeaker or hooter to create musical tunes, using a specific sequence of pulses. This produced a version of the national anthem in the autumn of 1951 and well-known carols at Christmas.
[Mark II was an in-house term for the Ferranti Mark I]
Important work was also done on programming languages. Turing was initially responsible for the original programming manual. His language used a 5-bit teleprint code, with a numerical system to the base 32. This proved too complex and idiosyncratic; users had to learn the 32 digits of the number base, their numerical equivalent, and their equivalent in binary notation. A revised Scheme B was compiled by Popplewell and Brooker, which was preferred by nearly all early Ferranti users.
In 1954 Brooker introduced the Mark I Autocode, a language with fewer machine-specific dependencies, which was easier to learn. It dealt with the problem of two-level storage and used simple conventions for control transfers, intrinsic functions, input/output and job control. Brooker’s autocode, which predated the heavily used Fortan languages, was one of the most influential Manchester innovations of this period.
We have a wealth of information about the Ferranti Mark I in our computing archives including: the Department of Computer Science collections (main and additional); Campbell-Kelly collection; Turing additional papers; Dietrich Prinz papers; Alick Glennie papers; Vivian Bowden papers; Durward Cruickshank papers and, of course, the Ferranti collection.
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