Home Forums Peripherals & Multimedia Peripherals printer plugged into UPS

It turned out DEC was going around our plant routinely replacing the disk cartridges in the various drives. The cartridges had been cleaned by a subcontractor that had a mis-calibrated head alignment device causing the heads to crash on the surface of the platters. One of our techs realized what was happening and stopped DEC from installing the rebuilt cartridges but not before eight drives on eight different PDPs had spectacularly self-destructed. As I recall those were 50 MB cartridges costing roughly $45,000 each and that does not count the thousands of engineering man-hours we lost waiting for the destroyed drives to be replaced and reloaded.

I've read at least a few accounts of BIG old drum hard drives suffering catastrophic failure. Usually the brake seizes unexpectedly. These things were the size of a washing machine, and had a ferrous drum about the size of the basket in them, that spun about as fast as your clothes washer does when it's on "spin". Think of all the inertial energy in a heavy ferrous drum spinning that fast.

Now, very suddenly, attach it to its enclosure.

Those things were usually bolted down, but not for that. More to prevent them from 'walking' around when spinning. Those little floor braces were no match for all those joules of energy. In rare cases you might find yourself being chased by the unit, as it tumbled on its side violently until the brake finally fully caught and the drum came to a stop.

Too bad recording surveillance cameras weren't around back then, I'd love to actually get to see one of those incidents.

Inertial mass can add up pretty quickly even when the moving bits aren't all that heavy.

I worked for the first place in Florida that had a color laser copier back at the start of the 90s. The first batch of color copiers on the market retailed for $30,000 and up, and were extremely rare; we would routinely get people to pay $15 to $30 *a sheet* for color copies and computer output. (The place I worked shelled out another $30,000 for a gizmo that would attach the copier to a computer, allowing us to do something that most people could only dream about--make printouts from a computer in full color.)

Canon spent quite a bit of time tinkering with the design of the first primitive color copiers, trying to speed them up. The very first ones had four big drums made of thin transparent plastic, large enough for an 11x17 sheet of paper to wrap around, and a tricky mechanism to pass off the paper from one to the next so that the paper could come into contact with each of the four toner/photosensitive drum assemblies.

As you can imagine, they were quite slow by today's standards, taking over a minute to make a letter-sized photocopy and several minutes for an 11x17.

When they tried to speed them up, the early units had a habit, if the paper misfed, of throwing bits of mechanism all over the place. If the paper jammed, the computer would stop the mechanism, but the feed drums spun quite quickly. Occasionally, the delicate mechanism would break on a misfeed, and then the service guy would come in and spend a few hours elbow-deep in the copier, muttering about inertial mass.