Take the 2-minute tour ×
Unix & Linux Stack Exchange is a question and answer site for users of Linux, FreeBSD and other Un*x-like operating systems.. It's 100% free, no registration required.

I just inherited a system and I am trying to understand it's partition table for the hard drive. (I'm new to this)

machine:~# fdisk -l /dev/sda

Disk /dev/sda: 250.0 GB, 250000000000 bytes
255 heads, 63 sectors/track, 30394 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000080

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1       30064   241489048+  fd  Linux raid autodetect
/dev/sda2           30065       30394     2650725    5  Extended
/dev/sda5           30065       30394     2650693+  fd  Linux raid autodetect

Why does the numbering go from 1 to 2 to 5. "What is on" sda2 and sda5?

share|improve this question
1  
For further reference you may be interested in Wikipedia's articles on MBR and extended (partition) boot records. –  Michael Kjörling Jul 21 '13 at 22:23

1 Answer 1

up vote 5 down vote accepted

On Linux traditional DOS-partitions will show up this way:

  • Partitions from 1 to 4 are primary partitions
  • Partitions above 5 are logical partitions.

In the DOS-partitioning-scheme (this is not Linux-specific) if you want to use logical partitions you have to define a pointer within one of the primary partitions for these. At this pointer the BIOS will find further information.

This pointer (sda2) shows in fdisk as id 5 "Extended" - it extends the partitioning-scheme to more than the default 4 partitions normally possible.

Now your system consists of two partitions:

One primary, bootable partition: sda1 (which was or is part of a linux-raid-array) and one logical partition: sda5 (which was or is part of a linux-raid-array).

There is no place left for additional partitions.

share|improve this answer
    
Technically it contains 2 primary partitions and one logical partition. –  jordanm Jul 21 '13 at 4:12
    
@jordanm Right - I corrected my answer accordingly - I knew I was missing the right term here... –  Nils Jul 21 '13 at 21:12

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.