Reply to post: Infinite booting

Sysadmin sank IBM mainframe by going one VM too deep

Paul Mitchell 1

Infinite booting

Back in the early 80s I was sys admin on a Honeywell DPS-6 used by about thirty developers.

I needed to reboot it one evening but I couldn't hang around to perform the boot myself. I had a tiny assembler program that would perform a "level-2 interrupt" . This would skip any shutdown malarkey and perform an immediate reboot.

I placed this command into the batch queue scheduled for 6pm. The other developers assured me they'd be gone by then. So I expected to arrive the following morning to find a freshly rebooted minicomputer.

Unfortunately, since the level-2 interrupt rebooted with so little bureaucracy, there was no chance for the batch processor to remove the job from the queue. The result being that as soon as the machine started up and looked in the queue it found the reboot command there ready to execute again.

This led to an infinitely looping reboot and a bunch of angry early-bird developers when I arrived the next day.

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