is there an Boot Sector or Partition Table on usb flash disk? - Hardware

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  1. is there an Boot Sector or Partition Table on usb flash disk?

    hi all,
    is there an Boot Sector or Partition Table on usb flash disk?



  2. Re: is there an Boot Sector or Partition Table on usb flash disk?

    "freegnu" wrote:
    > is there an Boot Sector or Partition Table on usb flash disk?


    Most usb flash disks contain a master boot record with a partition table.
    When mounting those disks you should do something like:

    mount /dev/sda1 /mnt/hd

    However, I have seen at least one mp3 player which didn't have partitions,
    instead it should be mounted with:

    mount /dev/sda /mnt/hd

    With such a usb flash disk you might be a little confused. The system has
    no way to know if there is a partition table and you might assume that the
    disk contains a partition table. By interpreting the contents in the
    beginning of the disk as a partition table you get something that looks
    like a broken partition table containing partitions with strange ids and
    geometries.

    regards Henrik
    --
    The address in the header is only to prevent spam. My real address is:
    hc8(at)uthyres.com Examples of addresses which go to spammers:
    root@variousus.net root@localhost


  3. Re: is there an Boot Sector or Partition Table on usb flash disk?

    thanks for your reply


    "Henrik Carlqvist"
    ??????an.2006.12.28.07.32.23.256848@deadspam.com...
    > "freegnu" wrote:
    >> is there an Boot Sector or Partition Table on usb flash disk?

    >
    > Most usb flash disks contain a master boot record with a partition table.
    > When mounting those disks you should do something like:
    >
    > mount /dev/sda1 /mnt/hd
    >
    > However, I have seen at least one mp3 player which didn't have partitions,
    > instead it should be mounted with:
    >
    > mount /dev/sda /mnt/hd
    >
    > With such a usb flash disk you might be a little confused. The system has
    > no way to know if there is a partition table and you might assume that the
    > disk contains a partition table. By interpreting the contents in the
    > beginning of the disk as a partition table you get something that looks
    > like a broken partition table containing partitions with strange ids and
    > geometries.
    >
    > regards Henrik
    > --
    > The address in the header is only to prevent spam. My real address is:
    > hc8(at)uthyres.com Examples of addresses which go to spammers:
    > root@variousus.net root@localhost
    >




  4. Re: is there an Boot Sector or Partition Table on usb flash disk?

    Henrik Carlqvist wrote:

    > "freegnu" wrote:
    >> is there an Boot Sector or Partition Table on usb flash disk?

    >
    > Most usb flash disks contain a master boot record with a partition table.
    > When mounting those disks you should do something like:
    >
    > mount /dev/sda1 /mnt/hd
    >
    > However, I have seen at least one mp3 player which didn't have partitions,
    > instead it should be mounted with:
    >
    > mount /dev/sda /mnt/hd
    >
    > With such a usb flash disk you might be a little confused. The system has
    > no way to know if there is a partition table and you might assume that the
    > disk contains a partition table. By interpreting the contents in the
    > beginning of the disk as a partition table you get something that looks
    > like a broken partition table containing partitions with strange ids and
    > geometries.
    >
    > regards Henrik

    Isn't this just a matter of how the device is set up? Could I just format
    the whole device to create /dev/sda or instead use cfdisk to make partition
    table and then format to yield /dev/sda1, /dev/sda2 ... etc?

    Haven't tried, just curious.

    Happy New Year!
    Roby

  5. Re: is there an Boot Sector or Partition Table on usb flash disk?

    Roby wrote:

    > Henrik Carlqvist wrote:
    >> Most usb flash disks contain a master boot record with a partition table.
    >> When mounting those disks you should do something like:
    >>
    >> mount /dev/sda1 /mnt/hd
    >>
    >> However, I have seen at least one mp3 player which didn't have partitions,
    >> instead it should be mounted with:
    >>
    >> mount /dev/sda /mnt/hd


    > Isn't this just a matter of how the device is set up? Could I just
    > format the whole device to create /dev/sda or instead use cfdisk to make
    > partition table and then format to yield /dev/sda1, /dev/sda2 ... etc?


    Most likely you can do that with an USB flash drive. After putting the
    partition table of you choice onto a USB drive you can also put your file
    systems of choice onto those partitions. However, I don't know what
    happens if I do that with my mp3 player. My guess is that my mp3 player
    has a firmware which has built in assumptions about having a vfat file
    system without any partitions. If I create file systems in partitions on
    that mp3 player the firmware might not be able to find my mp3 files. If I
    would place file systems like minix or ext3 on the mp3 player I'm almost
    sure that it will become unusable as an mp3 player. One day I might try
    this just to see what happens :-)

    regards Henrik
    --
    The address in the header is only to prevent spam. My real address is:
    hc8(at)uthyres.com Examples of addresses which go to spammers:
    root@variousus.net root@localhost


  6. Re: is there an Boot Sector or Partition Table on usb flash disk?

    hi all,

    this is what i have:
    i have a Transcend Jetflash 1 GB USB thumb drive.
    by default, it came with a file by the name mformat.exe , which i
    didnot execute.

    this is what i did:
    i installed RHEL 4 inside VMWare workstation. the base OS is WinXP.
    in GUI mode, i inserted the thumb drive in the USB port.
    this detected the hardware and said "Found new hardware in VMWare" (or
    something similar to that).

    initially fdisk -l only displayed /dev/sda1, /dev/sda2 and /dev/sda3.
    after the new hardware detection, it also displayed /dev/sdb1 . it
    reports /dev/sdb1 as a bootable partition and says that the start and
    end cylinders as 1 and 128, respectively. it says the file system type
    as FAT 16. it also said the following:
    "partition 1 has different physical/logical endings:
    phys=(126,254,63) logical=(127,122,59)"

    mount command says :
    /dev/sdb1 on /media/USB_DISK type vfat ()

    now when i do ls -la /media/USB_DISK, i am able to access the contents
    of my USB thumb drive.

    note that in all above:

    ***i have not manually partitioned my USB drive.

    ***i did not run kudzu command. it automatically detected the hardware.

    but this happens in GUI mode only and not in CUI mode.

    ***fdisk reports filesystem type as FAT 16, whereas mount says it is
    vfat.

    This is my experience with USB drive. don't know how useful this
    information is to you.
    please anybody add any information to my message above.

    thanks.

    freegnu wrote:
    > hi all,
    > is there an Boot Sector or Partition Table on usb flash disk?



  7. Re: is there an Boot Sector or Partition Table on usb flash disk?

    thank you for your reply Bill.
    Bill Marcum wrote:
    > On 2 Jan 2007 04:20:35 -0800, jeba
    > wrote:
    > >
    > > ***i have not manually partitioned my USB drive.
    > >

    > It was partitioned and formatted at the factory.


    i don't understand what is the file mformat.exe in my USB drive for. is
    it a repartitioning tool?
    > > ***i did not run kudzu command. it automatically detected the hardware.
    > >
    > > but this happens in GUI mode only and not in CUI mode.
    > >
    > > ***fdisk reports filesystem type as FAT 16, whereas mount says it is
    > > vfat.
    > >

    > fdisk looks at the partition ID byte. mount reads the actual partition
    > or device. vfat is a Linux driver that handles all FAT filesystems
    > including those with long filenames.

    thanks for the explanation.


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