20 May
2006
20 May
'06
4:56 a.m.
"Kelly Leavitt" wrote:
What I interpret what you said above to mean is that the interface between the
controller card and the ST-412 drive is not simply a digital interface. It is
acutally the MFM stream bi-directionally, and that the controller is what con
verts this to the system required digital stream, and the systems digital stre
am to the MFM stream.
Is this essentially correct?
This sounds right to me. It would not be hard to make something in
hardware to pull the clock and data back out. You'd then have (as I
recall) the raw bytes for each sector (i.e. header + data + trailer).
If you knew how the controller was programmed you could then easily find
the data. It should also be reasonble to create the stream in the
opposite direction. Some simple tests should prove it out.
I have not done the math but it seems like a PIC or one of the low end
ARM chips should be able to do this... worst case add a small CPLD to
aid in the serial in/out.
In other words, a ST-506 emulator. I'm pretty sure they exist as
commercial products. (but for some reason I never see them ebay or other
on-line auctions)
ps: I found this for any Apple Lisa Profie users
http://john.ccac.rwth-aachen.de:8000/patrick/idefile.htm
-brad