windows - when disk partitioning in ubuntu, wrong informations were detected

06
2014-04
  • KayKay

    when i check disk partition in ubuntu 9.04 using #fdisk -l my friend show me like this. i have 4 hard disks, but he didn't.. but only 3. Was there anything wrong? when i installed linux and maked config? (e.g> i have miss on setting disk partition matter) and when see below result, the device sda2, sda5 start same address, end too. is there anything wrong with my disk? i have seperated 4disks.. C:,D:, G:,H: please teach me when you know about this matter. thanks.

    Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xe9ffe9ff

Device     Boot     Start         End      Blocks   Id  System
/dev/sda1   *           1       10199    81923436    7  HPFS/NTFS
/dev/sda2           10200       19457    74364885    f  W95 Ext'd (LBA)
/dev/sda5           10200       19457    74364853+   7  HPFS/NTFS

Disk /dev/sdb: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xf16cf16c

Device     Boot      Start         End      Blocks   Id  System
/dev/sdb1   *           1       10199    81923436    7  HPFS/NTFS
/dev/sdb2           10200       19457    74364885    f  W95 Ext'd (LBA)
/dev/sdb5           10200       19457    74364853+   7  HPFS/NTFS
    • Answers
  • squircle

    Maybe the fourth "mystery disc" that you were seeing was the extended partition container for the logical partition /dev/sdb5. Your disc, when formatted with an MBR partition table, can only contain four primary partitions (sdx1, sdx2, sdx3, sdx4). If you want more partitions, one of the primary partitions can be made into an extended partition, which can contain logical partitions (sdx5, sdx6, sdx7 etc.). Hopefully that explains the discrepancy.

    The reason why sdb2 and sdb5 have the same start and end is because sdb2 is the extended partition, and sdb5 (the logical partition) fills the entire extended partition's space. Hope this helps!

    (I tried to interpret your question the best I could, but I can always clarify my answer if you clarify your question!)


    • Related Question

    linux - Understanding fdisk -l
  • KayKay

    When i entered #fdisk -l in unbuntu 9.04

    following is the result

    Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xe9ffe9ff

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1       10199    81923436    7  HPFS/NTFS
/dev/sda2           10200       19457    74364885    f  W95 Ext'd (LBA)
/dev/sda5           10200       19457    74364853+   7  HPFS/NTFS

Disk /dev/sdb: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xf16cf16c

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *           1       10199    81923436    7  HPFS/NTFS
/dev/sdb2           10200       19457    74364885    f  W95 Ext'd (LBA)
/dev/sdb5           10200       19457    74364853+   7  HPFS/NTFS

    But somewhat i can't understand following result.

    What is sdb? I searched through internet and knew 'sdb' is the primary slave. What is the primary slave though? What is the primary master? What is different between the two?

    and why sda2, sda5 start at same location?


    • Related Answers
  • krtek

    sdb is a second disk, given the results I think you have some kind of raid on your computer.

    sda2 and sda5 are on the same location because sda2 is an extended partition, it is a special partition which containts the logical partitions of your system. Finally, sda5 is the first and only one logical partition.

    More informations about disk partitioning : http://en.wikipedia.org/wiki/Disk_partitioning

  • Amazed

    In Linux, hard drives are listed with a three letter description like this:

    Interface Type Identifier

    With most disks these days, the interface is always recognized as being SCSI so the first letter is S for SCSI. The second letter D means that it's a drive. The final letter is assigned in alphabetical order from A to Z starting from the first enumerated device on the bus.

    The numbers which follow the three letter description indicate the partition number of a logical volume on the drive. All usable hard drives have at least one partition.

    An identifier such as /dev/sda5 therefore means it's the first SCSI hard drive, fifth partition.

  • sarnold

    For details, see: http://en.wikipedia.org/wiki/AT_Attachment

    Linux treats even parallel ATA drives as SCSI devices, they're close enough, and the SCSI code was far cleaner than the IDE code, so the change was made from /dev/hd* to /dev/sd* a while back.

    ATA only allows two drives per channel, so there's typically four two channels, each with a master and a slave.

    And the partition format has extended partitions starting at partition 5. Any non-primary partitions wind up being created 'inside 5', as it were. For full details, you'd probably have to read the source for fdisk or gparted.

  • Andrei Podoprîgora

    Well, sda and sdb are two different hard disks in your PC. sda1, sda2 ... are partitions on these disks.