Computers vs Arc Welding (Quick response needed)

[Mabry Tyson <TYSON@WARBUCKS.AI.SRI.COM>]

The wing of the building that SRI's AIC's computers has been evacuated for
earthquake repairs.  (The building has suffered damage and might not
survive another quake.  The vertical exterior supports are temporarily being
enhanced by steel supports.)

The repair crews want to do arc welding within about 25-30 feet of the
Symbolics (and Vax) CPUs.  They will be using a separate power supply so
noise (generated by their equipment directly) on our power supply.
However, we are worried about induced noise (from the arc) on our power
supply and on emissions that could affect our equipment.  These emissions
could affect the CPU itself (somewhat unlikely considering the 
Symbolics 3600/3670/3640 cabinents), the ethernet cable, transceivers, or
transceiver cables, the hirose or lemo cables between the CPU and the
consoles, color cables, serial lines (generally between Vaxen and terminals),
the disks, the cables between Symbolics CPUs and disks in racks next to
the CPU.

The hirose (and other extensions consisting of separate cables) are probably
going to be quite close (5' maybe) to the arc welding.

We moved most of our consoles into a separate wing but could not move
the CPUs.  They want permission to do arcwelding around the clock.  As it is,
it is difficult to work with everyone squeezed into less than one half the
office space and not a complete complement of lispms.  What used to be our
offices are inaccessible and packed or stacked up (eg, I don't know where
my desks, filing cabinets, or books are).  If we turn off our lisp machines
and Vaxen, we are essentially out of business for the week or however long
it takes them to do this.

(Of course, mail to SLUG will not go through while we are down.)

We have a test of arcwelding in a couple of hours.  If anyone has any
knowledge of how this may affect our systems, please send mail to
Tyson@AI.SRI.COM or call me at (415)859-5021.  If I am not in, please
talk to Doug Moran  (a secretary can switch you over) or leave a message.

Thanks!
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