Re: Nonstandard low-level formats and USB floppy drives (is linux capable?)

From: Dances With Crows (danSPANceswitTRAPhcrows_at_gmail.com)
Date: 02/10/05 

Date: 10 Feb 2005 03:45:34 GMT

On 9 Feb 2005 16:39:39 -0800, Luser staggered into the Black Sun and
said:
> I broke down and bought a USB floppy drive. Why do I need floppies,
> don't ask, but I do need them. In particular, I need HD 3.5 inch
> floppies, with nonstandard, i.e. higher capacity, low-level formats
> such as 1.722MB.
>
> However, with a USB floppy, apparently I only have one device,
> /dev/sda, through which I can access the floppy. Can Linux low-level
> format and mount nonstandard formats, such as 1722KB on USB floppies?

Good question. The standard utility, fdformat, uses ioctl()s that are
specific to "normal" floppy disk devices. Those ioctl()s fail if used
on SCSI devices. Therefore, I don't know if you can even lowlevel
format a floppy disk of any kind with a USB floppy drive. The
usb-storage module has a number of comments in it about a Uniform Floppy
Interface protocol that all USB floppy drives are supposed to use, but I
didn't see anything in there about it supporting the raw device commands
necessary to move the head to track N and lowlevel-format that track.

You should test the drive with a 1722K floppy made on a machine with a
non-USB floppy drive. If the USB drive can't read and write that
lowlevel format properly, you'll be kind of screwed no matter what.

There may be a way around this though. If you can lowlevel-format a
floppy using this drive on a Windows machine, you can use a program like
USBSnoopy ( http://www.wingmanteam.com/usbsnoopy/ ) under Windows to
figure out exactly what USB commands are sent to the drive to get it to
lowlevel-format a floppy. Then, you can take those commands, use libusb
to send them to the drive, and see if they work under Linux. Modify the
commands so they format 82 tracks at 21 sectors/track instead of 80
tracks at 18 sectors/track, and foom, you've got the ability to lowlevel
format a 1722K floppy. Adjust numbers to taste. Publish your results.
Make a kernel patch for the usb-storage module so that it can deal with
sending the commands required.

This seems like it'd be an interesting thing to fiddle with. My laptop
has a normal floppy drive and a 'Doze2K partition, so if I can find a
USB floppy drive, I'll have all the tools necessary to try all the crap
I wrote in the above paragraph. Let me know what you come up with; I'll
try to find a drive tomorrow.... 

-- 
Matt G|There is no Darkness in Eternity/But only Light too dim for us to see
Brainbench MVP for Linux Admin /    mail: TRAP + SPAN don't belong
http://www.brainbench.com     /                Hire me! 
-----------------------------/ http://crow202.dyndns.org/~mhgraham/resume

Relevant Pages

  • Re: Not able to format diskettes
    ... Floppy disk drives are sensitive to head alignment. ... the capacity of the blank/used disks. ... If I try to format it says it can't format: ... XP has some issue managing floppy drives? ...
    (microsoft.public.windowsxp.general)
  • Re: Win98 -- all kidding aside
    ... AND the floppy drive DOESN'T ... Stick a USB drive on your Ubuntu system, ... "Linux people" didn't. ... that I'm unaware of any Linux distro that ever handled floppy drives ...
    (Ubuntu)
  • Re: Floppy disk drive not reading disks
    ... I tried every suggestion I could find, including changing floppy drives 3 or ... have faulty floppy drivers, as, some people have no problem with floppies ... > When I try a quick format, message comes back "disk cannot be quick ... > Or, using the option to create a start up disk, message is "an unexpected ...
    (microsoft.public.windowsxp.hardware)
  • Re: cannot format floppy
    ... >to create a boot disk, ... Track 78 out of 80 won't format properly. ... If it's always at track 78 - then you have a floppy drive that is ... Since you can get brand new floppy drives for $10 put a new one in. ...
    (comp.unix.bsd.freebsd.misc)
  • Re: Is an optical burner obsolete now days?
    ... I won't admit to being old, but I remember feeding punched paper tape into a tape reader. ... For them I keep a USB floppy drive handy, ... Perhaps the most used medium of exchange that I have between computers ... (I have a very few systems with 2.88MB floppy drives. ...
    (alt.sys.pc-clone.dell)
Loading