3 Aug
2005
3 Aug
'05
3:31 a.m.
On Wed, 2005-08-03 at 05:58 -0400, Dave Dunfield wrote:
Hi Guys,
I'm really getting fed-up with the limitations of the PC floppy disk
controller.
Here's another idea I've had on the back-burner for quite some time, I've
mentioned to a couple of you during private correspondance, but here it is
for open discussion.
The idea is to make a small single-board computer with a microcontroller,
a WD2793 or similar floppy disk controller, enough memory to buffer a
few tracks, and a high-speed serial port for communication with the PC.
The board would have connectors for 5.25"/3" drives and 8" drives, and
would properly interface to all drive types.
Yep, although I still think that talking raw to the floppy drive
(buffering a track at a time) and processing in software's the way to
go..
I think I figured on about 256KB of static ram for the track buffer, 8x
sample rate. Z80 to do the processing (although memory addressing when
sampling / playing back data would be under control of a seperate
clock/up-counter for speed reasons). Say 32KB of workspace memory for
the Z80.
An addressable latch for the Z80 to control the floppy control lines.
I was actually thinking of a parallel interface, but serial works too.
Heck, stick that part of it on its own board and use whatever interface
you prefer (subject to ROM change or drivers for both in ROM, jumper
selectable).
256KB of static RAM doesn't seem to unreasonable (in terms of board
footprint) made with modern-ish parts.
Firmware would be developed to provide
read/format/write/analysis
capabilities around the more powerful WD chip. Images would be transferred
via the serial connection to and from the PC. This should allow us to
archive soft-sector formats that are not compatible with the PC, and also
to perform these functions under virtually any PC environment.
Is there anything the WD chip won't handle versus a raw track approach?
Hard-sectored disks? What about chances of error recovery?
I'm just having visions of an external catweasel equivalent (only
portable!) made from parts found in the average junk bin...
I just haven't had time to design and build the
board ... anyone else
interested in working together on such a project?
I'm interested in anything that's external to be honest. I think I'd
prefer something made out of 'classic' parts though (Z80 / 6502 / EPROM
etc.) rather than something that needed me to go out and buy a new-
fangled CPU, programmer etc. :)
cheers
Jules