Did you know?
A working replica of the Baby was later constructed so visitors could see this early computing technology in action.
Rebuilt for its fiftieth anniversary in 1998, Manchester’s pioneering stored-program computer became a working museum exhibit.
1 min read
An experiment with a future
Baby was an affectionate name for a precise technical achievement. Developed at the University of Manchester by Frederic Williams, Tom Kilburn and Geoff Tootill, the Small-Scale Experimental Machine successfully ran a program held in electronic memory on 21 June 1948. Its distinction was to be the first working electronic stored-program computer—not simply the first computer.
Its immediate purpose was to test Williams–Kilburn cathode-ray-tube memory, rather than offer a practical computing service. The main store held just 32 words of 32 bits: 1,024 bits altogether. Crucially, memory contained both data and instructions, allowing different calculations without rebuilding the circuitry.
Rebuilding the experiment
The original machine did not survive intact: it was developed into later computers. For its fiftieth anniversary, a Computer Conservation Society team led by Chris Burton, with six volunteer engineers, recreated it with ICL sponsorship and university support. Vintage electronic components and guidance from original designers helped make this a functioning reconstruction, not merely a convincing façade.
On 21 June 1998, the replica repeated Kilburn’s original calculation during anniversary proceedings in the museum’s 1830 Warehouse. It was formally handed over to the museum that day: a commemoration in which the machinery itself could participate.
History that still runs
The reconstruction makes an otherwise elusive experiment visible. Manchester’s Science and Industry Museum documented regular volunteer-led demonstrations in 2023, allowing visitors to watch early stored-program computing in operation. Demonstrations should not, however, be assumed to run every day; availability requires checking.
Baby’s importance extends beyond its modest memory. It led to the Manchester Mark 1, whose design informed the Ferranti Mark 1—an important passage from university experiment to commercial computing. The replica preserves not just an appearance, but something of how that transition began.