Though I'm not advocating someone install TSM or TSM on a mainframe,
I'll offer that we don't IPL our mainframe very often.  Here's the
output of a command I just entered ...

 q cplevel
VM/ESA Version 2 Release 3.0, service level 9803
Generated at 07/09/98 12:19:20 EST
IPL at 03/18/01 07:17:35 EST

But then the mainframe isn't as big as some of our Linux/AIX/Solaris
servers. ;-)

cheers, wayne