8 Sep
2023
8 Sep
'23
12:58 p.m.
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.
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?
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.
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?
Any pointers are appreciated!
Anders
www.andersknelson.com
8 Sep
8 Sep
1:09 p.m.
On 9/8/23 12:58, 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.
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?
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.
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?
Any pointers are appreciated!
Hard-sector or soft-sector? Easiest thing for most cases is to hook it
to a legacy floppy on a PC. Call the disk a 1.2MB 5.25" and you'll be fine.
--Chuck
1:15 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
1:16 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
3 p.m.
Hi Chuck,
The drive is a Qume Qumetrak 242 so I assume soft sector? I'm open to
correction.
On Fri, Sep 8, 2023, 4:15 PM 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
5:01 p.m.
On 9/8/23 15:00, Anders Nelson via cctalk wrote:
Hi Chuck,
The drive is a Qume Qumetrak 242 so I assume soft sector? I'm open to
correction.
Mostly. Most drives can, with the proper logic be made to read and
write hard-sector disks. You just don't get separate SECTOR/ and INDEX/
outputs.
I read hard sector floppies in an 842, for example and it lacks the
hard-sector support logic.
On the other hand, my Siemens FDD 200 have the logic, along with a
configurable sector divider (32,16,8 sectors) as well as an optional
data separator.
There is a lot of variation in 8" drives.
--Chuck
3:54 p.m.
I have had better luck with a P-III motherboard that connects to the 34-50
pin adapter in the middle and 8" on the other end. This way you can trick
the BIOS of the computer to think the 8" drive is a 1.2Mb 5 1/4". With
this set up I have made a bootable DOS 6.22 8" disk, so I know it works.
THEN use the USB port to copy files as a separate drive. The USB to floppy
devices are pretty good for 3.5" but I would not expect a direct adapter
from the 8" to be reliable.
Bill
On Fri, Sep 8, 2023 at 3:59 PM Anders Nelson via cctalk <
cctalk(a)classiccmp.org> 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.
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?
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.
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?
Any pointers are appreciated!
Anders
www.andersknelson.com
4:05 p.m.
On Fri, 8 Sep 2023, Bill Degnan via cctalk wrote:
I have had better luck with a P-III motherboard that
connects to the 34-50
pin adapter in the middle and 8" on the other end. This way you can trick
the BIOS of the computer to think the 8" drive is a 1.2Mb 5 1/4". With
this set up I have made a bootable DOS 6.22 8" disk, so I know it works.
THEN use the USB port to copy files as a separate drive. The USB to floppy
devices are pretty good for 3.5" but I would not expect a direct adapter
from the 8" to be reliable.
A USB to floppy device that supports 5.25" 1.2M "should" work.
A USB to floppy device that supports the 3.5" "mode 3"/NEC98 (360RPM
3.5")
might be coercible into working.
--
Grumpy Ol' Fred cisin(a)xenosoft.com
254
days inactive
255
days old
7 comments
5 participants
participants (5)
-
Anders Nelson -
Bill Degnan -
Chuck Guzis -
Fred Cisin -
Wayne S