Did Nasdaq get rid of the hp/tandem nonstop backends then? I don't think they did. As of 2008 they were still running them. They might have windows frontends and middle ware, though.
My first job in the Silicon Valley was on the Himalayas doing QA. They were awesome machines. QA meant pulling drives and cpus in the middle of processing, browning out/cutting power, etc.. it was wonderfully destructive :-)
http://www.onwindows.com/Articles/LSE-TradElect-system-goes-...
Microsoft used TradeElect as a centerpiece in their "Get the Facts" Linux bashing campaign.
http://www.microsoft.com/uk/getthefacts/lse.mspx
Microsoft should get a share of the blame, but it sounds like a borked implementation since NASDAQ runs on Windows.