The WSJ reports that yesterday's 7 hour outage at the LSE is due to a proprietary platform based on Microsoft technologies.
At the heart of the problem appears to be super-fast technology that has become critical to LSE and other exchanges. Traders experienced problems connecting to TradElect, a 15-month-old proprietary LSE platform developed with Microsoft Corp. technology that the LSE has touted as allowing it to expand and speed up its capacity for trades. "Microsoft is working with the London Stock Exchange to understand the root cause of the outage," said a Microsoft spokesman.
Realistically, this could have happened with any technology choice, but it's amazing to me that the LSE is not all *nix. Details are fuzzy, so maybe this is just a desktop as opposed to a core trading system.
As, this month was also the deadline for TradElect to reach 10,000 continuous messages per second. That's a pretty significant number and I can't point to a Microsoft success story processing that kind of volume.