Recovering data from corrupt floppy

[neelypeel]

Sorry - originally posted on Shouts:

I'm trying to recover a corrupted floppy from my aged parents windows machine (and thereby convice them of linux's superiority!).
It's not mounting (as either fat or ntfs)

"sudo dd if=/dev/fd0 of=/mnt/win/no_switches"
returns "input/output error"

"e2fsck -fv /dev/fd0" returns "Attempt to read block from filesystem resulted in short read while trying to open /dev/fd0 Could this be a zero-length partition"

"mount /dev/fd0 /mnt/win" gives "dmesg | tail" as

"[4304007.14000 floppy0: probe failed... [4304007.539000] floppy0: probe failed... [4304007.539000] end_request: I/O error, dev fd0, sector 0 [4304007.539000] Buffer I/O error on device fd0, logical block 0 [4304014.329000] floppy0: probe failed... [4304014.728000] floppy0: probe failed..."

Help!

[askrieger]

Re: Recoevering data from corrupt floppy

How have you defined /dev/fd0 in /etc/fstab? Is it listed as "auto"? I've found that it's best to just format ALL floppies (even those written by Linux for Linux) as fat. If your aged progenitors (who are probably younger than I) have a windoze machine, that floppy is absolutely, positively, fer shure, formatted fat.

That said, I suspect that the floppy is hosed.

[neelypeel]

Re: Recovering data from corrupt floppy

Heres the relevant line from /etc/fstab:

/dev/fd0 /media/floppy0 auto ,atime,noauto,rw,dev,exec,suid,user 0 0

Although I don't think I've ever played around with it...

Does that get me any closer?

[askrieger]

Re: Recovering data from corrupt floppy

I have a couple of comments/recommendations, but I only see one actual problem; If the comma at the beginning of the options block is real, remove it. Other than that, I would use "fat" instead of "auto" for the filesystem, as I mentioned above, It guarantees that I can use floppies for data exchange with windoze boxes and even macs. Also, this is the first time I've ever seen "atime" as an explicit floppy option (for one thing it's the default). Similarly, adding "dev" to the options is contradictory. Both "suid" and "exec" are security holes. You could insert a random floppy that had a malware program and it could run as root and take over your system, so I would omit "suid" and explicitly say "noexec", even though it is redundant. Adding "user" at the end of the option list automatically sets the options, "noexec", "nosuid", and "nodev". I would also explicitly add "rw" to the options for floppies. So, my floppy line says:

/dev/fd0	/media/fd0	fat	rw,user,noauto	0	0

Look "man mount" to understand the avaiilable choices.

[neelypeel]

Re: Recovering data from corrupt floppy

Thanks for the help so far!
Right, my floppy /etc/fstab line now reads

/dev/fd0 /media/floppy0 vfat rw,user,noauto 0 0

(vfat as suggested by mount when fat not recognised)

now, mount /dev/fd0 returns "can't read superblock"

I've had a root around on google to see if there's a way of getting further, but I'm not getting very far.
any more suggestions?

[neelypeel]

Re: Recovering data from corrupt floppy

Still trying -

fsck -V -t vfat /dev/fd0

returns

dosfsck 2.11, 12 Mar 2005, FAT32, LFN
Read 512 bytes at 0:Input/output error

Has it read 512 bytes? Is there any hope?

[askrieger]

Re: Recovering data from corrupt floppy

It's not clear to me that it actually read 512 bytes. It looks as if it tried to read the first 512 bytes and failed. I'd say that there's very little, if any, hope of success.