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[solved] usb floppy visible as /dev/sdb without a partition
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e3k
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PostPosted: Fri Mar 06, 2020 6:45 pm    Post subject: [solved] usb floppy visible as /dev/sdb without a partition Reply with quote

bought a gembird usb floppy drive. when i insert it with a diskette it shows /dev/sdb but no partition is visible.
i could write dd if=freedos of=/dev/sdb and could boot that on a 386 laptop.

Code:
modprobe floppy
modprobe: ERROR: could not insert 'floppy': No such device


Code:
ls /dev/fd/0
lrwx------ 1 root root 64 Mar  6 19:36 /dev/fd/0 -> /dev/tty1


Code:
lsusb
Bus 007 Device 002: ID 0644:0000 TEAC Corp. Floppy


normal floppy support and dosfs in kernel.

>>> https://forums.gentoo.org/viewtopic-p-7458810.html
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Last edited by e3k on Sat Mar 07, 2020 9:28 am; edited 1 time in total
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NeddySeagoon
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PostPosted: Fri Mar 06, 2020 7:41 pm    Post subject: Reply with quote

e3k,

Floppies are not partitioned. You mount the entire volume.
In days gone by, you formatted a floppy using a special /dev entry. /dev/fd0 was only used for normal filesystem access.
Code:
$ ls /dev/fd0*
/dev/fd0        /dev/fd0h1476  /dev/fd0H720   /dev/fd0u1743  /dev/fd0u3840
/dev/fd0CompaQ  /dev/fd0h1494  /dev/fd0h880   /dev/fd0u1760  /dev/fd0u720
/dev/fd0d360    /dev/fd0h1660  /dev/fd0u1040  /dev/fd0u1840  /dev/fd0u800
/dev/fd0D360    /dev/fd0h360   /dev/fd0u1120  /dev/fd0u1920  /dev/fd0u820
/dev/fd0D720    /dev/fd0H360   /dev/fd0u1440  /dev/fd0u2880  /dev/fd0u830
/dev/fd0h1200   /dev/fd0h410   /dev/fd0u1660  /dev/fd0u3200
/dev/fd0h1440   /dev/fd0h420   /dev/fd0u1680  /dev/fd0u3520
/dev/fd0H1440   /dev/fd0h720   /dev/fd0u1722  /dev/fd0u360
is all the supported formats on fd0.
Those are the standard ones. As PC floppies are soft sectored, companies could and did write there own non standard floppy formats, including spiral tracks. I've not seen that on a PC though.

All these things depended on having a real floppy controller, not something an the end of a USB interface.

As its effectively a SCSI block device, try to low level format it like any other SCSI block device. Its been a while since I've needed to do that.

Google suggests that you try ufiformat but its not in the ::gentoo repo.

Formatting only writes the soft sectoring information. The address and data marks and leaves the data regions empty.
It changes the floppy from erased to blank.
After a floppy is formatted, you make a filesystem on it. A journaled filesystem is a very bad choice. Try vfat.

Formatting involves a bit of trial and error at the start. The formatter writes the address and data marks on the first track, then checks the the last one has not overwritten the first one.
Spindle speed control is horrible. If the drive runs too fast, the first sector was destroyed by the last, so the formatter reduces the intersector gap and tries again ... and again.

Once it gets going, formatting tests the floppies surface.
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e3k
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PostPosted: Sat Mar 07, 2020 9:28 am    Post subject: Reply with quote

thank you NeddySeagoon:

Code:
mount /dev/sdb /mnt/usb


works fine.
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PostPosted: Sat Mar 07, 2020 11:28 am    Post subject: Reply with quote

e3k,

You don't need to partition a hard drive either but you can only put a single filesystem on it then.

Early PCs did not have HDD. The FAT filesysem of the day worked up to 32MB. (yep, mega) which was plenty for 360kB floppies and early HDD.
However, once HDD got to be bigger than 32Mb, you could only use the first 32Mb of your very expensive 40MB HDD.

The partition table hack was added as a workaround. The history of the PC is littered with backwards compatibility things like that.
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Jaglover
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PostPosted: Sat Mar 07, 2020 11:34 am    Post subject: Reply with quote

Definition of partition - a division into portions. In other words - cutting into pieces. You can partition a floppy disk if you want to. OTOH, why partition a drive for a single filesystem? Some DOS type operating systems may not able to read it, but who cares. I'm not sure if Windows can even read a USB drive which is not partitioned.
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e3k
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PostPosted: Sat Mar 07, 2020 4:58 pm    Post subject: Reply with quote

NeddySeagoon wrote:
e3k,

You don't need to partition a hard drive either but you can only put a single filesystem on it then.

Early PCs did not have HDD. The FAT filesysem of the day worked up to 32MB. (yep, mega) which was plenty for 360kB floppies and early HDD.
However, once HDD got to be bigger than 32Mb, you could only use the first 32Mb of your very expensive 40MB HDD.

The partition table hack was added as a workaround. The history of the PC is littered with backwards compatibility things like that.
you knowledge intrigues me. yes i need it for reading floppies dated in 90ties. mounts fine but when copying data from it some files seem to be broken. but not all.
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PostPosted: Sat Mar 07, 2020 5:09 pm    Post subject: Reply with quote

e3k,

I've lived through it.
Once upon a time I though a 5MB HDD was huge. :)

Floppies may degauss over the years, so you can only read patches of them.
A real floppy controller may do better that a USB adapter but that mean you need to find an old PC that still has a floppy connector on the motherboard.

How badly do you need the data?
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e3k
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PostPosted: Sat Mar 07, 2020 5:16 pm    Post subject: Reply with quote

NeddySeagoon wrote:
e3k,

I've lived through it.
Once upon a time I though a 5MB HDD was huge. :)

Floppies may degauss over the years, so you can only read patches of them.
A real floppy controller may do better that a USB adapter but that mean you need to find an old PC that still has a floppy connector on the motherboard.

How badly do you need the data?
i lived without that data for decades and i do not need them. just on a search for rare dos games ;)
yes the "old pc" is gone now. it had a real floppy
i remember once i had a 286 with 20MB. i knew all the file system structure. those were the times :)
...
by the way i have a 386 laptop with a real floppy which i could hook up via a parallel port but i do not know how to send data from dos 6 (could install freedos though..)
so that is why i bought this usb floppy to transfer data from it.
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PostPosted: Sat Mar 07, 2020 6:25 pm    Post subject: Reply with quote

e3k,

kermit (named after the frog) certainly works over a serial link.
I have a feeling that it could use a special cable between two parallel ports too but I've not done that.

A serial link will be slow but it works.
Code:
$ eix kermit
* app-misc/ckermit
     Available versions:  8.0.211-r4 (~)9.0.302 {ncurses}
     Homepage:            http://www.kermitproject.org/
     Description:         combined serial and network communication software package
that has to be it.
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Ant P.
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PostPosted: Sat Mar 07, 2020 6:27 pm    Post subject: Reply with quote

DOS came with the InterLnk.exe program. Basically a very early predecessor to SMB. You'd connect two machines with a parallel or serial cable, run the server on one machine (this being DOS, you can't do much else while it's running), and a TSR on the client. Very slow but it was fun watching win95 try to boot over a serial line.

I doubt there's anything in Gentoo for it but I'd be surprised if someone *hasn't* written a Linux client for it out there somewhere.
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