> On Jun 16, 2015, at 3:20 PM, tony duell <a...@p850ug1.demon.co.uk> wrote:
>
> ...
>> The actual tape movement as such, is all done by the small wheel next to
>> the head, which just runs the tape past the head.
>
> Which is essentailly the same as the capstan in an audio tape recorder,
> albeit the computer
> drive doesn't have a pinch roller
Most don’t. Some do. I remember using IBM tape drives on a 360 Model 44 that
were amazingly badly designed.
Part 1: two capstans spinning all the time, in opposite directions.
Solenoid-activated pinch rollers would press the tape against the capstan to
set it moving. The same solenoid-activated pinch roller moved in the opposite
direction would press the tape against a non-moving “capstan" to stop it.
Part 2: vacuum columns — no surprise there. But why on earth would anyone
build a vacuum column that has the oxide side of the tape facing OUTward,
rubbing the oxide against the column side walls?
Amazingly enough, those drives did work reasonably reliably, but I would never
want such a beast in my shop.
paul
