On the Emulation of TU58s

Mark J. Blair nf6x at nf6x.net
Tue Jun 16 10:25:29 CDT 2015

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.

Emulating the whole tape drive is pretty easy since it helpfully interfaces over a plain old asynchronous serial port. But replacing the whole drive with an emulator, or worse yet tethering its computer to a modern computer, leaves a bit of an empty feeling if one likes their vintage machines to be original. There's something missing when you don't hear the drive whirring, and the system boot completes within a modern attention span.

But what about emulating the tape cartridge, instead? Imagine a gizmo in the form factor of a TU58 cartridge, containing a wheel for the capstan roller to engage, but connected to an encoder instead of the ******* ************ ***** ** **** belt drive of an original cartridge? Where the tape would normally be exposed, there is instead a magnetic head which rests against the tape drive head like in one of those gizmos for injecting line level audio into an audio cassette drive. It might need an external power source, but for the sake of argument, let's pretend that a suitable rechargeable battery can be embedded. Maybe it has an SD card slot on the rear, or maybe it looks just like a real TU58 cartridge when inserted, and you swap the whole thing to change tapes (this is open for discussion).

Would this be more or less acceptable in terms of keeping the system as close to original as possible, vs. unplugging the original drive and plugging in a drive emulator?

No, I'm not going to build the thing. I'll just build my TU58 drive emulator to fit in the cartridge slot but plug into the computer in place of the original drive, with the cables snaked through the original drive mechanism. And I'll feel a little bit dirty, but the thing will work reliably and will be easy to implement. I'm just curious about the philosophical implications of my silly cartridge emulator idea.

Mark J. Blair, NF6X <nf6x at nf6x.net>

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