On the Emulation of TU58s

Johnny Billquist bqt at update.uu.se
Tue Jun 16 12:31:26 CDT 2015

On 2015-06-16 18:21, Paul Koning wrote:
>> On Jun 16, 2015, at 12:10 PM, tony duell <ard at 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.


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