[tjalfi]

I've also heard of teams that shut down the mainframe for an hour during a time change. It's an easy way to avoid application issues for a small amount of downtime.

[nubinetwork]

We used to do this on several hpux servers at $dayjob. However 95% of those servers have long since been decommissioned, and the remaining server didn't actually need it to begin with. (It was really anything that had an oddball database that needed it)

[TylerE]

If it runs Unix is isn't a mainframe.

Only half joking.

[nine_k]

I would say it's 90% not joking.

A mainframe has hardware different enough to require a different approach to the OS.

Of course a modern variant of System 390 happily runs tons of Linux VMs.