Quote from propseeker:
yes, i've written both execution and simulation... don't forget data, that's important too.
the number of symbols in and of itself won't be a problem for most brokers, but as a result of running many symbols your order frequency and messages per second can cause major problems. most will either bump you or throttle you. those who don't and don't have the infrastructure to support you will experience the thrill of their mission critical client server go down at the worst time (don't ask me how i know). other limitations? there are too many to list... from 0 ack disconnects, to server downtime, data issues/errors, reg sho auto-handling (or lack thereof), poor risk control, ad infinitum. its cost me low 6 figures a year handling these limitations in real-time and i honestly feel lucky it doesn't cost me more.
so, to answer chaos' question why i don't use open source for trading applications... because when things go wrong (and they will), i like to have some idea of where the problem may lie, and if i wrote every line, i'll have a very good idea. only way i'll use opensource is as someone mentioned at the beginning of the thread, for ideas. otherwise, the entire design must be considered, the structure understood, every line gone over and stress tested and if not then it's a trust gamble. and if i'm going to do a trust gamble with mission critical code... you can bet that dev is going to be VERY well compensated, and there's going to be MAJOR accountability. there's enough chance in trading, this is one area i try and eliminate any i can find.