6 May
2021
6 May
'21
7:47 p.m.
On May 5, 2021, at 10:37 AM, Chuck Guzis via cctalk
<cctalk at classiccmp.org> wrote:
?On 5/5/21 5:18 AM, Paul Koning wrote:
We had a room on the ground floor at ETA that housed an MG set that ran the CY205 (and
maybe the 835 and 875 too) in the basement. They had isolated the MG from the mounting
pretty well in addition to sound proofing the room because with door closed, you couldn?t
really tell it was in there? which was nice because the room was right off the main entry
hallway :-)
Chris
An earlier message commented on the whine from
power converters. I
don't know how common this practice was, but at the University of
Illinois PLATO system which had a pair of 6500 systems, the
motor-generator was located near the elevator machinery in a corner
of the building, far from the computer room. Yes, it was noisy, but
no one spent any time in that location. The computer room was -- by
mainframe standards certainly -- rather quiet. Of course it helps to
have liquid cooling, so there weren't many noisy fans to deal with.
It was the "white noise" from the vacuum pumps in the tape drive banks
that drove me nuts after a few hours. After 8 hours or so, I sometimes
found my hands shaking. Of course this facility had a very large
machine floor with several full-sized installations. Eventually,
management provided ear protection.
As far as any "whine"--I vaguely recall hearing a high-pitched whine if
I put my ear close to the power adjustment panel in a CDC Cyber--but it
was barely audible.
As far as the MG sets themselves, I never went there--any noise at
SVLOPE was drowned out by the fans in the cooling tower. I don't recall
where the power equipment at ARHOPS was located.
--Chuck