8 Sep
2023
8 Sep
'23
1:21 p.m.
Sent from my iPhone
On Sep 8, 2023, at 13:16, Wayne S
<wayne.sudol(a)hotmail.com> wrote:
> but presents itself to an OS as a Mass Storage Device (block device).
Anders, for what practical purpose would you do that?
It’s not like there’s so many 8 inch floppies around to make it feasible. You would have
to have a LOT of intelligence in the Usb interface due to the different physical formats
let alone the software formats.
It would be difficult.
8 Sep
8 Sep
2:57 p.m.
New subject: 8" DSDD to USB MSD?
Hi Wayne,
For sure the controller would have to do a lot more, but I know firmware
pretty well and BIOS/ancient OSes not at all! 😅
On Fri, Sep 8, 2023, 4:22 PM Wayne S via cctalk <cctalk(a)classiccmp.org>
wrote:
Sent from my iPhone
On Sep 8, 2023, at 13:16, Wayne S
<wayne.sudol(a)hotmail.com> wrote:
> but presents itself to an OS as a Mass Storage Device (block device).
Anders, for what practical purpose would you do that?
It’s not like there’s so many 8 inch floppies around to make it feasible.
You would have to have a LOT of intelligence in the Usb interface due to
the different physical formats let alone the software formats.
It would be difficult.
3:20 p.m.
New subject: 8" DSDD to USB MSD?
>>> but presents itself to an OS as a Mass
Storage Device (block device).
> Anders, for what practical purpose would you do
that?
> It’s not like there’s so many 8 inch floppies around to make it feasible.
> You would have to have a LOT of intelligence in the Usb interface due to
> the different physical formats let alone the software formats.
> It would be difficult.
On Fri, 8 Sep 2023, Anders Nelson via cctalk wrote:
Hi Wayne,
For sure the controller would have to do a lot more, but I know firmware
pretty well and BIOS/ancient OSes not at all! 😅
It would still be handy to have a USB device that operates as a "normal"
fully functional FDC.
It would make it possible to add floppies to devices without them, and/or
add more or different floppies to devices that do have them.
The basic software for it could be in flash RAM in the same USB device.
Source code for the IBM PC BIOS was published.
For floppies, you need Int13h, and there is a table of parameters pointed
to by Int1Eh.
Handling formats other than PC, auch as CP/M, P-System, TRSDOS, MS
Stand-Alone BASIC, Mac "1.44MB", etc. would require additional code.
--
Grumpy Ol' Fred cisin(a)xenosoft.com
3:27 p.m.
New subject: 8" DSDD to USB MSD?
I agree, and that generic USB FDC is already available:
https://github.com/dhansel/ArduinoFDC
If I can simply select 5 1/4 floppy mode and it'll work with an 8" disk, I
guess I don't need anything else?
On Fri, Sep 8, 2023, 6:20 PM Fred Cisin via cctalk <cctalk(a)classiccmp.org>
wrote:
>>>
but presents itself to an OS as a Mass Storage Device (block device).
> Anders, for what practical purpose would you
do that?
> It’s not like there’s so many 8 inch floppies around to make it
feasible.
> You would have to have a LOT of intelligence
in the Usb interface due to
> the different physical formats let alone the software formats.
> It would be difficult.
On Fri, 8 Sep 2023, Anders Nelson via cctalk wrote:
Hi Wayne,
For sure the controller would have to do a lot more, but I know firmware
pretty well and BIOS/ancient OSes not at all! 😅
It would still be handy to have a USB device that operates as a "normal"
fully functional FDC.
It would make it possible to add floppies to devices without them, and/or
add more or different floppies to devices that do have them.
The basic software for it could be in flash RAM in the same USB device.
Source code for the IBM PC BIOS was published.
For floppies, you need Int13h, and there is a table of parameters pointed
to by Int1Eh.
Handling formats other than PC, auch as CP/M, P-System, TRSDOS, MS
Stand-Alone BASIC, Mac "1.44MB", etc. would require additional code.
--
Grumpy Ol' Fred cisin(a)xenosoft.com
3:48 p.m.
New subject: 8" DSDD to USB MSD?
> It would still be handy to have a USB device that
operates as a "normal"
> fully functional FDC.
On Fri, 8 Sep 2023, Anders Nelson wrote:
I agree, and that generic USB FDC is already
available:
https://github.com/dhansel/ArduinoFDC
If I can simply select 5 1/4 floppy mode and it'll work with an 8" disk, I
guess I don't need anything else?
An 8" drive and a 5.25" 1.2M drive look the same to whatever they are
connected to, with a few trivial exceptions
8" is 50 pin; 5.25" is 34 pin.
The very first 1.2M 5.25 that I encountered (purchased at a swap) was a
pre-release/prototype? Mitsubishi 4854, and had a 50 pin connector!
I heard from some of the usual unreliable sources that when the AT BIOS
was being modified for 1.2M, some of the programmers thought that IBM was
adding an 8" drive!
8" is 77 track, 1.2M is 80 track. Therefore, trying to format an 8" disk
as 1.2M without special software will fail on tracks 77-79
For writing, TG43 provides write pre-compensation. not needed for
reading.
BTW, 8" power connectors were not standardized, so different brands of
drives will need different connectors.
READY/DISK-CHANGED on pin 34 was not standardized, and can confuse the
system is wrong.
Ideally, you would also want 8" SSSD, as that was "THE STANDARD" format
for CP/M.
The PC formats are/were all 512 bytes per sector; other formats had 1024,
256, and occasionally 128.
Many PC FDCs can not handle FM/SD, and many can't handle 128 bytes per
sector.
I;m forgetting numerous other items, so those are left as an exercise for
the reader :-)
--
Grumpy Ol' Fred cisin(a)xenosoft.com
5:08 p.m.
New subject: 8" DSDD to USB MSD?
On 9/8/23 15:20, Fred Cisin via cctalk wrote:
pretty well and BIOS/ancient OSes not at all! 😅
It would still be handy to have a USB device that operates as a "normal"
fully functional FDC.
It would make it possible to add floppies to devices without them,
and/or add more or different floppies to devices that do have them.
The basic software for it could be in flash RAM in the same USB device.
I use a STM32F4 MCU for my floppy work (and my tape work also). Half a
meg of program flash and 192KB of SRAM on-chip, running at 168MHz. But
my interface is strictly by image file. The USB connection is strictly
for file transfer and terminal operation. One does a whole disk at a
time, since the bulk storage interface is SD Card. Currently, I'm
limited to 32GB there.
I'm interested in recovering data, not running games.
--Chuck
11 Sep
11 Sep
1:49 a.m.
New subject: 8" DSDD to USB MSD?
On 2023-09-08 20:08, Chuck Guzis via cctalk wrote:
I use a STM32F4 MCU for my floppy work (and my tape
work also). Half a
meg of program flash and 192KB of SRAM on-chip, running at 168MHz. But
my interface is strictly by image file. The USB connection is strictly
for file transfer and terminal operation. One does a whole disk at a
time, since the bulk storage interface is SD Card. Currently, I'm
limited to 32GB there.
You have this somewhere on GIT?
464
days inactive
467
days old
6 comments
5 participants
participants (5)
-
Anders Nelson -
Chuck Guzis -
emanuel stiebler -
Fred Cisin -
Wayne S