[Coco] Regarding a cheap floppy emulator

[Christopher Smith]

So, given that I may need to build my CoCo disk system from parts anyway, I've been looking at the possibility of emulating one out of two floppy drives in hardware.  There is at least one very impressive floppy emulator available which will do everything I want, but it's upward of $100 and the budget isn't so great for now.  I'm looking at the possibility using a Chinese import emulator from ebay.  Supposedly it will emulate a 720k, 1.2M, and 1.44M floppies.  Now, of these formats, I'm reasonably sure the CoCo won't like any but the first.  That may be sufficient.  Here's what I'm considering:

I have a Teac 5.25" drive on order.  It's high-density, but people say that these things have an RPM jumper on them which will slow the spindle down.  You can then either force them to double-density mode or have them function as quad-density.  People also say that the quad-density disks will work out ok under OS-9.  I'd like to fit a switch onto the density selector so that I can force the drive into either double or quad density mode at any given time.  So that should make one good drive.

I'm also thinking about trying one of those floppy emulators.  It would need to be forced into 720k mode, and would basically work similarly to the 5.25" disk in quad-density mode, I suspect.  The downside is that the emulated disks would be smaller than usual under DECB, and unless I flipped sides there either by attaching another switch that mucks around with the side select signal on the cable or in software, I lose half of the space in a disk image that I might have still had.  Though, OS-9 should use them at full capacity, one would think.  My other problem here is that I strongly suspect that this emulator will not have drive select jumpers, so I may need to end up clipping pins, or -- who knows what, really -- to get the drives in the order I'd like.  Really I think the emulated floppy should be drive 0 and the actual floppy 1.

Any comments or suggestions on how to do this or why it's a bad idea and something else should be done instead? :)

All that aside, I'll still have the problem of housing the drives.  I've recently salvaged an old case that had a CD-ROM in it, which should be sufficient for a single drive, but I don't really have anything appropriate for two drives.  A standard (and as small as possible) PC power supply of even 60W or so should do fine for power, I think.  As for the box, I'm not quite sure what to do there.  Perhaps wood I could do on my own.  Maybe I could have something fabricated out of metal.  Something else?  Any ideas here will be welcome as well.


Chris

-- 
Christopher Smith
Systems Engineer, Wolfram Research