I interface to the mainframe using CICS transaction gateway from my web apps. Mainframes are the bomb when it comes to uptime. I don't remember the last time we had an emergency IPL. Plus they're fast, and when your application is architected right and using the mainframe in the places it does the best, you can't beat it. Just don't buy into IBM's claims of running Linux on them. The IFL is a joke, unless you have more money than you know what to do with. If you did, then you'd should just go out and buy a Linux blade center.