C++SIM/JavaSim

Back in 1990 my friend Dan McCue and I were doing work on replica management and a way to compute the optimum number and location of replicas to achieve a desired level of availability. (Yes, availability is not necessarily proportional to the number of replicas.) We needed to do some simulation work and started out with Simula, which is a nice language but which neither of us had much experience at the time. Both of us were (are?) C++ die-hards, so we decided that the best way would be to build out own simulation toolkit in C++, and C++SIM was born.

C++SIM was very successful for us (thanks to Isi for helping with some of the statistical functions). It has been used in a number of academic and industrial settings. It was probably one of the early open source offerings too, since it was made freely available by the University. I learnt a lot from developing it, not least of which was multi-threaded programming: this was the age before the general availability of thread-aware languages and operating systems. Sun's Lightweight Process package in SunOS had been around for a few years and Posix Threads was still in its infancy. But when you want to run simulations on different operating systems, it was impossible to target the same thread package. So I wrote a thread abstraction layer for C++SIM, as well as a couple of threading packages (ah, setjmp/longjmp were my best friends back then).

In 1996 I ported C++SIM to Java, and JavaSim was born (I've never been that good with sexy names!) Because of the massive adoption around Java, JavaSim saw more uptake than C++SIM. It was also easier to implement and maintain than C++SIM. Again, over the intervening years it's had a lot of use and I'm still getting feedback from people asking for updates or just reporting how they are using it (them).

Now the problem was that their current homes were limiting. The source code repository changed several times and I didn't have direct access to maintain it. The web site was also outside of my control once I left the University. So I finally got agreement from them to move it outside and change the licence to something a bit more modern. I've been working on this shift for about 9 months (though it's really only taken me a couple of weeks to do), but JavaSim/C++SIM now have a new home in Codehaus. The move isn't quite complete (I still need to find the source for the docs), but it's a start.