On 2015-06-16 18:21, Paul Koning wrote:
On Jun 16, 2015, at 12:10 PM, tony duell <a...@p850ug1.demon.co.uk> wrote:
As long as we're talking philosophy, what do y'all think about emulating the TU58
drive, vs. emulating the TU58 > *tape*?
I cannot properly express my opinion of that tape cartridge design even if I
violate list rules about use of
profanity. But the drive itself isn't all that bad, aside from not having
enough motors to manipulate a
well-designed tape cartridge mechanism.
The tape cartridge (along with QIC cartridges, etc) is an interesting design.
Of course the general problem is
to run the tape at constant linear speed past the head while winding it off one
reel onto the other. In general
there have been 3 solutions to this.
Another solution is to avoid the problem entirely by not requiring constant
linear speed. That’s what DECtape (the real one) does.
And yet another (possibly the most common one on computers) is to have a
small drive wheel that pulls the tape at constant speed across the
heads, and then have some other construction that drives the tape reels
depending on tape tension or length. Think vacuum columns or spring
loaded arms.
And then we have drives like the TU80/TU81 which do not seem to fit into
any of the mentioned categories. I'm not entirely sure how they work,
but I think they are similar to the DECtape in this sense.
Johnny
