The Manchester Small Scale Experimental Machine (nicknamed the Baby) was built at the University of Manchester
shortly after the Second World War. Heavily influenced by the ideas of John Von Neumann and company at the Moore
School, Freddie Williams, Tom Kilburn and Geoff Tootill built the first operational stored program computer. This
was a massive step in the development of the computer allowing programs to be executed from an electrical rather
than an electro-mechanical store with the order of magnitude increase in speed that this brings. The machine was
built primarily to test out the use of tubes as a storage device and is the first use of the Williams Tube as it
later became known.
Background
The first program to be executed looked for the highest factor of one number. On 21st June 1948 they were using very small numbers like 19 in the morning, and 3142 in the afternoon. The reliability had to be improved before they could run the 2^18 number taking 53 minutes. After this date, the experimental machine was expanded upon and led to the development of the Manchester Mark 1 and later the Ferranti computers. In preparation for the 50th anniversary of the first program's execution, a replica of the original machine was built at Manchester by a team lead by Christopher Burton a member of the Manchester Computer Conservation Society. Christopher was of great help in advising on matters of historical accuracy for this simulator of the Baby.
The replica of the Baby can be seen on display at the Museum of Science and Industry at Manchester and on certain days of the week can be seen in operation. The team were kind enough to give me a guided tour on my trip to Manchester in April 2014 and I was able to finally try out the real thing.
The original version is written in java
and requires a JVM supporting Java 1.2 or later to be installed and is still available to download. Full source code is included,
as is a detailed user
guide and an indepth discussion of the historical accuracy of the simulator. The simulator was written for the 
184 Kb PDF File
1.59 Mb Zip Archive