CERN installs its first electronic computer: The Ferranti Mercury

30 June 1958

CERN's first computer, a huge vacuum-tube Ferranti Mercury, was installed in 1958. It was one million times slower than today's large computers. Though the Mercury took 3 months to install – and filled a huge room – its computational ability didn't quite match that of a modern pocket calculator. "Mass" storage was provided by four magnetic drums each holding 32K × 20 bits – not enough to hold the data from a single proton-proton collision in the Large Hadron Collider. The Mercury ran a simplified coding system called Autocode – a type of programming language with a limited repertoire of variables. 

At the end of its career the Mercury was connected online to the Missing Mass Spectrometer experiment. In 1966 it was shipped to Poland as a gift to the Academy of Mining and Metallurgy at Cracow. Although it was quickly taken over by transistor-equipped machines, a small part of the Mercury remains in the CERN IT department. The computer's engineers installed a warning bell to signal computing errors – the bell is mounted on the wall in a corridor of building 2.

See video: "Computing at CERN in 1965" (features the Ferranti Mercury)

Technical specifications

Ran at CERN from 1958 to 1965
First generation vacuum tube machine
60-microsecond clock cycle, 2 cycles to load or store, 3 cycles to add and 5 cycles to multiply 40-bit longwords
No hardware division
Magnetic core storage (1024 40-bit words, 120-microsecond access time)
Processor with floating-point arithmetic and a B-Register (an index register)
Magnetic-drum auxiliary storage (16 Kwords of 40 bits, 8.75 msec average latency, 64 longwords transferred per revolution)
Paper tape I/0
Two Ampex magnetic-tape units added in 1962
Autocode compiler


Computing at CERN

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