What this DOESN'T do is disable interrupts. User stuff grinds to a halt,
but life goes on for the interrupt handlers and all attached to them,
like SCSI, networking (arp, ping) etcetera. To kill the handlers, cli().
That's easy, but I don't know exactly where to put it. [Richard Johnson
did. I'm reading digest as I write this]
As for what Linux _should_ do, my vote's currently for killing the
handlers. Although the previously mentioned AIX box that routed packets
during OS installation sounds really cool, my gut says most sysadmins
_expect_ the box to stop everything when told to.
Don't like my opinions? I've got others!