8 Sep
2023
8 Sep
'23
12:16 p.m.
Sent from my iPhone
On Sep 8, 2023, at 13:15, Fred Cisin via cctalk
<cctalk(a)classiccmp.org> wrote:
On Fri, 8 Sep 2023, Anders Nelson via cctalk wrote:
Hi all,
I just bought a very clean, DSDD 8" disk drive off eBay and it has a 50p
connector which I guess is the common Shugart type? I also found a 50p->
34p adaptor PCB design someone documented online.
very few of the lines need to be rearraanged, so you can just twist a few wires in a
cable. One exception is that if you need the TG43 signal for writing, then you will need
additional circuitry.
> I haven't delved much into floppy formats (high level or low level) but I'm
> somewhat familiar with filesystems from FAT12. My ultimate goal is to
> create an open-source USB
adaptor that
reads/writes the contents of an 8"
disk but presents itself to an OS as a Mass Storage Device (block device).
Is such a thing possible?
Sure. Ine the very early days of external USB floppies, there existed a rare few in
which the circuitry was a general purpose FDC. All currently produced ones are locked in
to only supporting a couple of PC 3.5" formats. Look for "mode 3", which
is support for the NEC format, which is compatible with 8" formats, IFF you can
modify the hardware to work.
I once created a terrible custom format for
storing data on a flash chip
which required no low-level format, but I expect a magnetic disk needs
headers/trailers to know when a track starts/stops so it can skip around.
Yes. It is called "IBM format", but that is confusing, since it is talking
about the track structure that IBM designed (3740?), NOT about IBM PC (which does use that
structure)
I checked out the KyroFlux website and it seems
there are dozens of formats
that were used for 8" disks - is there a favorite format among the
community that allows full use of a 1.2MB 8" disk?
Not everybody will agree, but, . . .
NEC modified their 3.5" drives to be 360RPM, same as their 5.25" 1.2M drives,
and 8" drives. Thus, they used the same format on all three sizes!
http://www.xenosoft.com/fmts.html#8
--
Grumpy Ol' Fred cisin(a)xenosoft.com