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