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 Baby's switch panel, taken in December 1948
Unlike most other simulators that exist (including one I developed previously for
RISC OS) this attempts to accurately simulate the switch panels that were used to laboriously program the machine
along with many of the idiosyncracies that would have resulted from its incorrect use. I'm told by one of the
volunteers at the museum that the simulator is used to help them practice using the replica and in
planning tests for the replica when it requires repair.
The simulator was updated by Gulzaman Khan, an undergraduate student at the University of Manchester for the 60th
Anniversary celebrations in 2008. The updated simulator was used for a competition for the public to write programs for the
baby as part of the celebrations (ironic given I first became aware of the machine as a result of reading about a similar
competition for the 50th anniversary).
Gulzaman's update means that the GUI is now a photo-realistic representation of the replica machine and can run as
a java applet or can be downloaded and run as an application. Press the 'Stop/Run' switch in the bottom left corner of
the simulator to see it in action. A full reference manual and brief getting started guide are on the University of Manchester
page about the simulator.
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 History
of Computing course as part of my BSc in Computer Science at the University of
The simulator's tube - old plain-GUI simulator
The simulators's switch panel - old plain-GUI simulator
Digital 60 simulator with full user guide
Alan Burlison's blog about visiting the replica
- Alan helped with some improvements to the source code
before Gulzaman's update.
BBC Manchester article Mar 2008
- about the 60th Anniversary celebrations and the simulator.
PC Plus article Jan 2010
- about the Manchester Baby and how to use this simulator.