Quoted: This is the original version! Martin Graetz provided us with a printed version of the source. We typed in in again - it was about 40 pages long - and re-assembled it with a PDP-1 assembler written in PERL. The resulting binary runs on a PDP-1 emulator written as a Java applet. The code is extremely faithful to the original. There are only two changes. 1)The spaceships have been made bigger and 2) The overall timing has been special cased to deal with varying machine speeds.

Simulator, emulating the operation of EDSAC, one of the world's first stored-program computers.

Quoted: The Edsac simulator is a faithful software evocation of the EDSAC computer as it existed in 1949-51. The user interface has all the controls and displays of the original machine, and the system includes a library of original programs, subroutines, and debugging software. The simulator is intended for use in teaching the history of computing; as a tutorial introduction to the classic "von Neumann" computer; or as an historical experience for current computer practitioners.