MBR, File system, boot sector, partition table

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

Someone know where are on the disk these:

partition table,
boot sector,
MBR,
fat or ntfs table

And how can i find them with a disk hex viewer?
How much bytes their are long?

Thanks
3 answers Last reply
More about file system boot sector partition table
  1. Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

    djake@excite.it (djake@excite.it) wrote:

    > Someone know where are on the disk these:
    >
    > partition table,

    The 64 bytes from offset 406, in the MBR.

    > boot sector,

    May be located anywhere on the disk. Its location is pointed by the active
    partition entry in the MBR. Usually, the boot sector will be found in logical
    sector 63 (011 in CHS notation) but don't count on it.

    > MBR,

    The very first sector on the hard drive (logical sector 0, or CHS 001).

    > fat or ntfs table

    The FAT can be found after the boot sector. With FAT-32, the FAT usually begins
    on the 33rd sector from the boot sector, but that number may vary, depending on
    how the FAT-32 partition was created.

    By NTFS table I suppose you mean MFT (master file table). The MFT starts
    somewhere at the beginning of the NTFS partition (NTFS has no FAT) at a location
    that is specified in the boot sector.

    > And how can i find them with a disk hex viewer?

    Try any of the many disk viewers available - some are free, like PTEDIT. You
    may also try the free version of RESQDISK. Norton DiskEdit is a commercial disk
    viewer and editor. Be careful with changing data as from your questions, you
    have a great deal to learn before you can manipulate these elements without
    doing harm to your data, or lose it.

    > How much bytes their are long?

    Disk sectors are 512 bytes in size, and that applies to the MBR and boot sector.
    The boot sector of a FAT-32 partition actually consists of three adjacent
    sectors (aka "extended boot sector") and there are two copies thereof with the
    mirror at seven sectors apart. The size of the FAT depends on the partition's
    size and varies from hundreds of sectors for FAT-16 (256 max) to thousands of
    sectors per FAT copy (there are always two) for FAT-32. The MFT size varies
    according to the number of entries it contains.

    May I suggest that you read about the subject on the web. Start with a google
    search on "file system disk structures" (just a little over one million hits) ;)
    then narrow down your search per subject.

    > Thanks

    Regards, Zvi
    --
    NetZ Computing Ltd. ISRAEL www.invircible.com www.ivi.co.il (Hebrew)
    InVircible Virus Defense Solutions, ResQ and Data Recovery Utilities
  2. Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

    Zvi Netiv <support@replace_with_domain.com> wrote:

    > djake@excite.it (djake@excite.it) wrote:
    >
    > > Someone know where are on the disk these:
    > >
    > > partition table,
    >
    > The 64 bytes from offset 406, in the MBR.

    Correct that to "The 64 bytes from offset 446, in the MBR"

    Regards
    --
    NetZ Computing Ltd. ISRAEL www.invircible.com www.ivi.co.il (Hebrew)
    InVircible Virus Defense Solutions, ResQ and Data Recovery Utilities
  3. Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

    "Zvi Netiv" <support@replace_with_domain.com> wrote in message news:k931p0t1q44kj9a742bd6hru51e7ejs3ai@4ax.com
    > djake@excite.it (djake@excite.it) wrote:
    >
    > > Someone know where are on the disk these:
    > >
    > > partition table,
    >
    > The 64 bytes from offset 406, in the MBR.
    >
    > > boot sector,
    >
    > May be located anywhere on the disk.

    In theory.

    > Its location is pointed by the active partition entry in the MBR.

    Or the EPBR for extended partitions.

    > Usually, the boot sector will be found in logical sector 63

    LBA 63. That would be the first partition boot sector. Others will be at
    offset 64 to the start of the EPBR (which is pointed to from the MBR).
    And from a partition perspective the bootsector is sector 0.

    > (011 in CHS notation)

    Then that would be 0/1/1 in CHS notation, not 011.
    And only with 63 sectors per logical track.

    > but don't count on it.

    Right, primary vs without primary partitions and sectors per track and so on.

    >
    > > MBR,
    >
    > The very first sector on the hard drive (logical sector 0, or CHS 0/0/1).
    >
    > > fat or ntfs table
    >
    > The FAT can be found after the boot sector. With FAT-32, the FAT usually begins
    > on the 33rd sector from the boot sector, but that number may vary, depending on
    > how the FAT-32 partition was created.
    >
    > By NTFS table I suppose you mean MFT (master file table). The MFT starts
    > somewhere at the beginning of the NTFS partition (NTFS has no FAT) at a location
    > that is specified in the boot sector.
    >
    > > And how can i find them with a disk hex viewer?
    >
    > Try any of the many disk viewers available - some are free, like PTEDIT.
    Well, that isn't a disk editor.

    > You may also try the free version of RESQDISK.

    > Norton DiskEdit is a commercial disk viewer and editor.

    So is WinHex (sort of) but it can be used in Trial mode.
    It lets you navigate to the partitions and to the bootsector, FATs and root-
    directory within the partition(s).

    > Be careful with changing data as from your questions, you
    > have a great deal to learn before you can manipulate these elements without
    > doing harm to your data, or lose it.
    >
    > > How much bytes they are long?
    >
    > Disk sectors are 512 bytes in size, and that applies to the MBR and boot sector.
    > The boot sector of a FAT-32 partition actually consists of three adjacent
    > sectors (aka "extended boot sector")

    > and there are two copies thereof with the mirror at seven sectors apart.

    Six.

    > The size of the FAT depends on the partition's
    > size and varies from hundreds of sectors for FAT-16 (256 max) to thousands of
    > sectors per FAT copy (there are always two) for FAT-32. The MFT size varies
    > according to the number of entries it contains.
    >
    > May I suggest that you read about the subject on the web. Start with a google
    > search on "file system disk structures" (just a little over one million hits) ;)
    > then narrow down your search per subject.
    >
    > > Thanks
    >
    > Regards, Zvi
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