Many people have complained that the simulator only runs on DOS/Windows, and a number have volunteered to produce alternative simulators, e.g. in Java. Such offers are much appreciated, but it's proving hard to know which ones to take seriously, so here's what we're going to do. If you produce an alternative simulator (or other useful tool for the competition), send us a very brief description and a URL (preferably a web page, but an FTP URL will do) and we'll link to it from this page.
A Java version of the simulator written by Brian Nenninger.
A version for Acorn Arm-based machines by David Sharp.
Another PC simulator by Geoff Sullivan.
A disassembler implemented as an Excel spreadsheet by Tom Cox.
An alternative assembler with extra features by Jozsef Rieth, and another one by Ron Kneusel. (Obviously, if you use an alternative assember, as a number of people have done, you will need to provide the snapshot file, rather than the assembly code, in your entry.)
To be useful, a simulator must reproduce the instruction set behaviour of the machine exactly. Make sure you check the programmer's reference manual carefully. If you are totally confident that your simulator is correct, you could ask us to verify it with view to making it an official alternative version. It will only be feasible to do this for a very small number of cases, though.
To offer a simulator, (or other software), email email@example.com with the heading COMPETITION SOFTWARE OFFERED. Please note that we can only maintain links to your software, we can't host, maintain, or field queries on the software itself (unless we make it official, as described above).
Incomplete Java source code (zip format) can be downloaded from here.
Disclaimer: Alternative simulators offered on this page have not been verified by us, and we do not guarantee that a program which runs correctly on one of them will run on the real machine. You are strongly advised to use the official simulator to do a final check that your program runs correctly.