[cctalk] Re: 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?
[cctalk] Re: 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
[cctalk] Re: 8" DSDD to USB MSD?
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
[cctalk] Re: 8" DSDD to USB MSD?
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 ci...@xenosoft.com
[cctalk] Re: 8" DSDD to USB MSD?
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@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 >
[cctalk] Re: 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 ci...@xenosoft.com
[cctalk] Re: 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 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 ci...@xenosoft.com
[cctalk] Re: 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 ci...@xenosoft.com
[cctalk] Re: 8" DSDD to USB MSD?
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 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 ci...@xenosoft.com >
[cctalk] Re: 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 wrote: > > > Sent from my iPhone > > > On Sep 8, 2023, at 13:16, Wayne S 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. > > >
[cctalk] Re: 8" DSDD to USB MSD?
Sent from my iPhone > On Sep 8, 2023, at 13:16, Wayne S 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.
[cctalk] Re: 8" DSDD to USB MSD?
Sent from my iPhone > On Sep 8, 2023, at 13:15, Fred Cisin via cctalk 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 ci...@xenosoft.com
[cctalk] Re: 8" DSDD to USB MSD?
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 ci...@xenosoft.com
[cctalk] Re: 8" DSDD to USB MSD?
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
