4 Jul
2025
4 Jul
'25
3:55 p.m.
On Jul 4, 2025, at 12:32 PM, Mark Kahrs via cctalk
<cctalk(a)classiccmp.org> wrote:
Jon Elson's take hits home. A 780 was delivered and VMS was running. We
installed 4.1BSD and it ran fine until it crashed. Field service insisted
we needed a full set of RS-232 wires in our cable. Still crashed
(surprise!). Switched to VMS, still crashed after a while. Local field
service couldn't find it. The big guns flew in from Maynard. First day:
Couldn't find it. Second day: "What, what's that wire doing there? Have a
wire-wrap tool?". Removed wire from backplane. Boots, runs. Engineer
flies home.
My story is about a 750. Under maintenance it ran for some time until the
tape drive failed. Tech installs new controller board, fixed.
Then the CPU fails. New CPU, fixed.
Then the tape drive failed again. New board, fixed.
And so on through various peripherals, disks, tty’s, etc.
Eventually they send out a guy who sits with it for a day, poking and prodding just
about everywhere for a while. At the end of the day says that he’ll be back tomorrow
with the correct part.
The correct part: A new backplane.
Took the entire day to remove/replace the hardware, and lo - the machine never failed
after that.
David
You can know the name of a bird in all the languages of the world, but when you're
finished,
you'll know absolutely nothing whatever about the bird... So let's look at the
bird and
see what it's doing -- that's what counts. I learned very early the difference
between
knowing the name of something and knowing something.
--Richard Feynman
David Barto
barto(a)kdbarto.org