Cambridge Museum Celebrates LEO, the First Business Computer, at 75

Business computing reaches its 75th anniversary this month, and the Centre for Computing History in Cambridge is marking the occasion with a celebration of LEO, the machine that helped launch the field.

The LEO@75 event will run on Saturday, November 28, from 10 a.m. to 5 p.m., featuring film screenings, historical displays, and hands-on activities for children.

The Centre for Computing History is an interactive museum just off Coldhams Lane in Cambridge. In 2018, it received National Lottery funding to help preserve, archive, and digitize a range of LEO Computers artifacts, documents, and personal memories.

Admission supports the museum charity. Student and concession tickets cost £10, and family tickets start at £15. In addition to adult-oriented programming, including a film screening, the event will offer activities for younger children (ages 5–7) and a Python coding session for older children (ages 12–16).

LEO—the Lyons Electronic Office—was an early computer, but from a distance of three-quarters of a century it can be easy to overlook just how early it was. Its design was based on Cambridge University’s EDSAC, developed by a team led by Sir Maurice Wilkes. EDSAC itself drew directly on John von Neumann’s influential and incomplete “First Draft of a Report on the EDVAC,” which circulated in 1945. That draft was based on the proposal for EDVAC, four years before the hardware was delivered.

That same year, John Mauchly and J. Presper Eckert completed ENIAC, EDVAC’s predecessor. In its original form, ENIAC was programmed by setting switches and reconnecting cables; EDVAC, by contrast, was designed to store its instructions in memory.

The report described what is now known as the “von Neumann architecture.” Wilkes and Douglas Hartree drew on those ideas while developing EDSAC, LEO’s immediate forerunner and one of the world’s earliest practical stored-program computers. The first working electronic stored-program machine was the Manchester “Baby,” the Small-Scale Experimental Machine, which ran its first program in 1948.

EDSAC ran its first program in May 1949—a few months before the delivery of BINAC, Eckert and Mauchly’s first stored-program machine. LEO ran its first commercial application in 1951. That was also the year the US Census Bureau took delivery of Eckert and Mauchly’s UNIVAC I.

Source link