On Fri, Apr 20, 2018 at 3:17 PM, Ron Natalie <ron@ronnatalie.com> wrote:

Drums were usually fixed head, although those UNIVACers out there will remember the Fastrand drums which had flying head.   Massive units looked like 6' lengths of sewer pipe covered in iron oxide.
It was sort of the basis of UNIVAC storage units.

​And big and did I say really noisy ....  We had 4 of them and they so so noisy CMU partitioned the machine room so they they were by themselves.  The CPUs and the operators were on the other side of glass wall.    ​I was looking at an old pic of me in the CMU machine room circa '76.  You can see console to the 1108 and the top of the door to the 'Fastrand' room (which was also the Vax serial #1 was for space reasons); but unfortunately one of the 360/67's 1Meg memory units (we had 4 - each a was a little larger than Vax 780 cabinet) is in the way, so the drums can not been seen.

One thing I'll never forget was when the first time they powered up CMU's first KL10 (which was DEC's first ECL based system).    It too was an early unit and DEC Pittsburgh had not been trained on them yet.   Unfortunately, the on-site provisioning was mistakenly set up for a KA10, which was horribly insufficient.   Well, the tech's blew every circuit breaker in the building - shutting down everything.

The emergency lights came on and room was eerily quiet, not a single fan running, but there was this strange humming coming from Fastrand room.      There was so much stored energy in the drums, they keep spinning for a very long time.