Re: PC as Apple II External Disk Drive?

[dempson@actrix.gen.nz (David Empson)]

Greg Lindhorst <gregli@email.msn.com> wrote:

> There was recently a short discussion on using a Commodore drive drive from
> an Apple through the external floppy interface.
> 
> Idea:  Could a PC emulate an external Apple II disk drive, through its
> parallel port?

I don't know about the technical specifications of the enhanced versions
of the PC parallel port, but I'd be surprised if a standard PC parallel
port could cope.

There is no clock signal available - everything is timed using nominally
4 microsecond bit cells, but the emulated disk drive would have to look
for a bit edge to work out where to start timing from (for writes - read
timing is driven by the "drive", so would be slightly easier; it still
needs to be 4 microseconds per bit cell).

Actually achieving the timing may be tricky without hardware support.
If I was going to try to build such a system, my preferred method would
be to build some simple electronics that handle the bit-level timing,
and allow data to be transferred in and out of the PC on a less strict
basis.


Assuming you could get past these issues, the rest of it should be
feasible.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand