Assume v. Presume

[Wildebeest]

That brings back back memories - one of my early workplaces had a Wang Room!

 

[EEPhil]

Remember seeing those washing machine style disks on a visit the University Computer Centre ops room back in late 70s or early 80s. Were connected to ICL 1900 at the time. Not sure whether the DEC VAX was there then. And don't forget the joys of the tape machine, card reader and probably a paper tape reader. Back in the user area card punch machines and teletypes.

 

[antipodean]

Wang Disk Pack...
View attachment 7918
http://www.obsoletecomputermuseum.org/wang/

Ah, the good old 150MB disk pack, IIRC there was also a 300MB version. I remember servicing the 150MB ones we had in service that were connected to a minicomputer system that we dealt with. Everyone (except maybe IBM) used drives made by Dataproducts IIRC, painted and rebadged for the particular system they were attached to. These were mean machines, put a pack in, push the go button and the motor that would please any washing machine had it up to speed in about 15 seconds at which point the floor moved as the heads loaded. Doing a head alignment on these machines involved some scary manipulation of things as the 'voice coil' that moved the heads was no respecter of fingers or tools if it decided to suddenly unload. When the heads were actively seeking the raised floor tiles would be having a minor earthquake under your feet.

The smallest version we had was a 6MB single platter pack that used a drive that also had a 6MB fixed platter. That drive was made by a company called Dynex, and I recall seeing adverts in Byte magazine for a version that you could use with CP/M systems.

 

[antipodean]

Disk Pack - saw one in person at Wang Computers' "Computer Room" - this was "a while back"! Loaded into what looked like a top-load washing machine.

Memory and Storage timeline: https://www.computerhistory.org/timeline/memory-storage/
Disk File (ignoring spelling in the picture below ) - https://www.facebook.com/photo.php?fbid=10226006035928890&set=p.10226006035928890&type=3
IBM 305 RAMAC "Random Access Method of Accounting and Control" - https://en.wikipedia.org/wiki/IBM_305_RAMAC
View attachment 7917

Woah, the days of head per track systems. I remember being shown such a system when I was going around doing interviews while deciding where to work for my first job straight out of secondary school. They were the wonder of the age at the time.

 

[antipodean]

I have a funny story about these pack drives. The computer company I worked for had a bureau running a Burroughs mainframe that a number of these pack drives. Occasionally one would get an error that took it off line, so the operators got in the habit of doing a power down/up to bring it back online. eventually the word went out that if an engineer needed to be called for a fault you DID NOT power down the drive but left it for the engineer to read whatever fault codes he could glean from it.

It proceeded to have a fault on Friday night, but the company had been too parsimonious to have weekend cover, so the drive was left running all weekend. Whatever the fault was the drive proceeded to have a head crash - on the top platter. This caused the head to wear through the platter until it was no longer attached to the spindle and landed on the one beneath, causing that to wear through as well. By the time the engineer arrived on Monday morning there was a heap of crashed platters and a spindle still happily rotating. Result a complete rebuild of the head system and a new disk pack please.

 

[EEPhil]

Surely the operator could write down the error code and then do a power down/up. The engineer has the code and there aren't bits of shattered disk everywhere.

 

[Black Hole]

parsimonious

That's a good word!