Keeping printers quiet broke disks, thanks to fuzzy logic • The Register

On Call Welcome once more to the Friday frolic that is On Call, The Register's forum for your tales of heroic rescues achieved against the odds.

This week, meet a reader we'll regomize as "Darren," who shared a story of his time in a Philadelphia hospital in the 1970s.

Darren was not in the hospital to be healed!

Rather, he was there when it moved a patient billing app from a mainframe to a few Wang 2200s.

If you don't remember the 2200, Wikipedia has a solid article about the all-in-one machine that explains how Wang incorporated a keyboard, cassette drive, and display into a single chassis – and allowed them to be networked to shared disk storage.

Think of it is a rickety proto-SAN.

We mention this because the 2200s Darren tended used shared storage – more of the Winchester disks we mentioned in last week's On Call – which was placed in a room alongside some dot matrix printers.

Dot matrix printers of the era made a distinctive and unpleasant buzz, so the room housing them and the shared disks had been carpeted to prevent that din escaping into the hospital.

These particular printers were really noisy, so the carpet ran all the way up the walls to the ceiling.

And because this was the 1970s, the carpet was a rich, red, shag. Darren reckons that choice was an early version of fuzzy logic.

All went well for a week or so. Then the disks crashed – hard. Darren was called out to sort them out.

"In those days, disk drives were too big to be sealed as they are today," he explained. "Air to fly the heads and to cool the electronics came through a large, very effective air filter."

When Darren arrived to investigate the outage, he found that air filter "completely clogged by a half-inch-thick mat of red fuzz."

It was not hard to spot the culprit. As all new carpets do, this groovy one shed fibres – so many fibres that they clogged the air filters.

"The solution involved the hospital buying a stock of air filters and training staff on how to change them every few days," Darren recalled.

Cleaners were therefore instructed to vacuum both the floor, and the walls.

"As the new carpet's fuzz shed rate tapered off, so did the frequency of air filter changes," Darren recalled.

But problems persisted and eventually the hospital repurposed part of the uncarpeted mainframe room to house the disks and printers.

That move was made possible with the addition of longer cables back to the Wang 2200s.

"The cables, though expensive, cost far less than the acreage of red plush carpet," Darren concluded.

Has tech you tend ever become a fashion victim? If so, share your story with a mail to On-Call. Keep 'em coming, dear readers, as the On Call mailbag could use a few more yarns to consider. ®

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