Re: A2 5.25" drive on a PC?

["josephoswaldgg@hotmail.com" <josephoswald@gmail.com>]

sicklittlemonkey wrote:
> This is a neat idea, and I don't think the 6502 is necessary or even
> desirable
> for this sort of device.
>
> > Sounds pretty much like an Apple II with a nibble copier in that dongle.
>
> More like an Apple II drive card (AKA Woz Machine) and a driver on the
> host
> PC to interface it to an emulator. The WM could be implemented in
> software
> on a microcontroller with enough RAM (say 8 or 16k) to buffer a track
> of nibbles
> (plus some timing info to handle nonstandard disks).

Yes but microcontrollers that support so much RAM in an efficient
enough way to handle a whole-track buffer are pretty much on an equal
level with a 6502, but with the disadvantage that the cycle timings are
all different, so you have to redesign an RWTS routine that is
equivalent to the 6502 version in order to support writing, except in a
"track-at-once mode" or something. Implementing the woz machine state
controller in software on a microcontroller is also going to be *very*
tricky. The hardware version runs absolutely cycle-for-cycle
predictably at a 2 MHz clock rate.

That pretty much means you are making a microcomputer roughly as
powerful as the Apple II+Woz machine in your dongle, or giving up
single-sector writes.

For read-only purposes, you could basically dump the read pulses
sampled at a 2 MHz rate or so, into a FIFO, then process it on the host
PC.