[Coco] floppy controller update

[Chuck Youse]

Hope I'm not spamming y'all, just trying to keep you all in the loop.

So I slapped together an OS-9 booter for the 82077 - I'll post it on the
web page shortly - and I can successfully load the boot file via the
controller.  NitrOS-9 still craps out because it can't open /dd, but
that's for another day, I guess.

The only serious problem at this point is what can only be termed
abysmal performance.  During the boot process, I'm only getting slightly
more than 1Kb/s (essentially 4-5 sectors/second) on the reads.  I've
tracked it down to the period of time between when I issue the read to
the controller and the time it exits non-DMA mode (once the transfer is
complete).  Ideas:

1. Interleaving?
2. Head load/unload times?

I wonder if anyone else has more experience with the nerdlies floppy
drives and might be able to lend some insight.

C.