jbray%bbn-unix@sri-unix.UUCP (07/12/83)
From: James Bray <jbray@bbn-unix> It seems to me that the real point is being steadily overlooked in this discussion. I forget whether I my original response to the list or not, so I will say again: it sounds like the machine is getting hung in a tight loop somewhere waiting for something that it is sure is going to happen which isn't happening. For example: once, at my last company, we had an intermittent problem with our Perkin-Elmer 3220 the symptoms of which were that it would hang in the boot on a Sense-Status instruction waiting for the disk. Vinnie, the field-service guy (and a good one) never did figure it out. He eventually did something that shouldn't have had any effect, but it went away. We agreed that it was a (dread) backplane problem. If you halted the machine under these circumstances, you would see that it was executing either the sense-status instruction or the immediately-following branch. What was happening was pretty obvious: it was a hardware problem, and needed to be fixed. So: whether you continue your machine or reboot it would seem to be a rather secondary consideration. The important thing would seem to be to get the PC and other context, find out what is going on, and fix it. --Jim Bray P.S. I attempted to send this out the other day, but a bunch of weirdness resulted and I don't think it made it (I didn't get a copy back). Apologies to those who get multiple copies.