8 Sep
2023
8 Sep
'23
8:15 p.m.
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