destroy DOS disks

This is a discussion on destroy DOS disks within the Linux Programming forums, part of the Platform Specific Boards category; howdy, my box has 2 partitions a 20GB linux RH 7.2 kernel 2.4.7-10 and a 40GB WinME. The problem is ...

  1. #1
    In The Light
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    destroy DOS disks

    howdy,
    my box has 2 partitions a 20GB linux RH 7.2 kernel 2.4.7-10 and a 40GB WinME.
    The problem is when i mount a DOS floppy in linux and read from it (no writing) it becomes unreadable in WinME, in fact it cant even be reformated. WinME issues an error something like. this disk is damaged and can not be formated, replace the disk.
    CD's work fine and mounting the windows partion from linux works fine.
    any ideas??

    M.R.
    I don't like you very much. Please post a lot less.
    Cheez
    *and then*
    No, I know you were joking. My point still stands.

  2. #2
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    Exactly HOW are you mounting it? Even if you are just issueing the mount command, /etc/fstab specifies exactly how to mount the floppy. I can guess, but if you post the exact command you use (if you mount -t), or the line from fstab, I can give a more exact answer.

    starX
    www.axisoftime.com

  3. #3
    and the hat of int overfl Salem's Avatar
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    You could just move the little "write protect" tab on the disk itself.

  4. #4
    In The Light
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    howdy,

    this is the line from /ect/fstab that mounts the floppy.
    Code:
       /dev/fd0   /mnt/floppy    auto   noauto,owner,kudzu   0  0
    i used code tags to simulate the spacing of the fstab line

    i use the KDE desktop menu to mount the floppy like this
    system - disk management - /mnt/floppy.

    Hey salem thats a good idea i'll try that when i get done here to see if it will protect the disk.

    Thanks

    M.R.
    I don't like you very much. Please post a lot less.
    Cheez
    *and then*
    No, I know you were joking. My point still stands.

  5. #5
    Registered User stautze's Avatar
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    make sure you umount before you eject the disk.
    'During my service in the United States Congress, I took the initiative in creating the Internet.' - Al Gore, March 9, 1999: On CNN's Late Edition

  6. #6
    Registered User billholm's Avatar
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    Yah you should try to unmount it. Linux does something to the disk's filesystem before it uses it, though I don't exactly know how.

    I use Loop Linux (DosLinux) , but my disks become unreadable by DOS only when I write directly into the device driver instead of the mount directory. I wonder why... it should have the same effect, shouldn't it?
    All men are created equal. But some are more equal than others.

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  7. #7
    Registered User stautze's Avatar
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    linux is famous for rendering disks unuseable if they are not unmounted properly...
    'During my service in the United States Congress, I took the initiative in creating the Internet.' - Al Gore, March 9, 1999: On CNN's Late Edition

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    It's like I thought, you are mounting it as "auto", which makes mount try and guess the filesystem. As you've probably guessed, it's not always very good at this. Change the line so it looks like this:

    Code:
     /dev/fd0   /mnt/floppy    vfat  noauto,owner,kudzu   0  0
    That will tell mount to always mount the floppy as a fat32 filesystem, which dos *SHOULD* be able to read (converted to msdos type). If dos still can't read after you've tried this, try changing "vfat" to "msdos". Sometimes dos doesn't like doing the conversion, but I rarely have a problem with it.

    I've actually seen this problem on my own system before, and "vfat" does the trick. That's what most floppies are default formatted to these days anyway, so it should work no questions asked. If you have any other filesystem disks (like ext2 or ext3) use:

    Code:
    mount -t *filesystem* /dev/fd0 /mnt/floppy
    as root, where *filesystem* is the name of the filesystem on the floppy. Then you can copy the data somewhere else, format it back in windoze, and re-use.

    Hope this helps
    ---------------
    starX
    www.axisoftime.com

  9. #9
    In The Light
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    howdy,
    hey thanks StarX, i wondered what exactly that "auto" meant. I've made the change in fstab so tomorow i will try it and see if vfat works.

    just goes to show you the people on these boards realy do know stuff.

    Thanks

    M.R.
    I don't like you very much. Please post a lot less.
    Cheez
    *and then*
    No, I know you were joking. My point still stands.

  10. #10
    Registered User stautze's Avatar
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    i can't see how the auto function is causing the problem you described. But if you want you could change it you do something like this:

    Code:
    /dev/fd0     /mnt/dos        msdos    rw,nosuid,dev,exec,noauto,user,async   1 0
    
    /dev/fd0     /mnt/linux      ext2     rw,suid,dev,exec,noauto,user,async     1 0
    Notice that dos partitions have no SUID or SGID bits.

    BTW, Did you ever try "umount" before you ejected the disk?
    Last edited by stautze; 06-28-2002 at 05:11 AM.
    'During my service in the United States Congress, I took the initiative in creating the Internet.' - Al Gore, March 9, 1999: On CNN's Late Edition

  11. #11
    In The Light
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    howdy,
    BTW, Did you ever try "umount" before you ejected the disk?
    yes, the disk was still rendered unreadable.


    M.R.
    I don't like you very much. Please post a lot less.
    Cheez
    *and then*
    No, I know you were joking. My point still stands.

  12. #12
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    stautze,

    I'm not saying it does it on every system all the time, but sometimes the auto fs detect can't figure out it is looking at an msdos or vfat floppy, and decides that it is actually ext2. The result winds up being a lot like what happens when you copy from your linux part to your windows part; it can't preserve ownership, but the files look unchanged. Putting them on the floppy, windows will get a whole bunch of what it thinks is junk data, and figure that there has either been a disk error or it's the wrong fs, or something stupid like that.

    Like I said, I've run into this problem on my system, as well as on a few others.

    starX
    www.axisoftime.com

  13. #13
    Registered User stautze's Avatar
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    >Like I said, I've run into this problem on my system, as well as on a few others.

    Eperience is a valuble thing, and I don't really have alot of it when it comes to sharing files with windows and linux.

    Seems to me that the "suid" option should be set to "nosuid" for all dos files systems, so there is no user or goup file permissions written to the cd? I think the default is suid...
    'During my service in the United States Congress, I took the initiative in creating the Internet.' - Al Gore, March 9, 1999: On CNN's Late Edition

  14. #14
    Registered User billholm's Avatar
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    Question

    Hey guys! I've reformatted my floppy into the ext2 filesystem, I copied into it the files needed to boot Linux, but it wont boot linux when I restart my pc with floppy boot as first priority: it just reads the disk, but bypasses it and proceed to booting my windows hd. How come?
    All men are created equal. But some are more equal than others.

    Visit me at http://www.angelfire.com/my/billholm

  15. #15
    In The Light
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    howdy,

    Bill Gates owns your box, he can't even believe you are trying to boot into an open source OS.



    actually i've never booted Linux from a floppy

    M.R.
    I don't like you very much. Please post a lot less.
    Cheez
    *and then*
    No, I know you were joking. My point still stands.

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