Partition, drive and volume and SYSTEM_DRV

hard drivepartition

I am checking the hard drive on my new Lenovo T400 laptop, where Windows 7 has been installed.

System Information of Windows 7 says there are three partitions 1.17 GB, 221.95 GB and 9.77 GB, but there are only two drives: C: of 221.95 GB and Q: of 9.77 GB.

Disk Management reports there are three volumes: Lenovo_Recovery(Q:) of 9.77 GB, SYSTEM_DRV of 1.17GB and Windows7_OS(C:) of 221.95 GB. All of three are simple layout, basic type and NTFS. Plus SYSTEM_DRV has status as healthy (SYstem, Active, Primary Partition), Lenovo_Recovery(Q:) is healthy(Primary Partition) and Windows7_OS(C:) is healthy (Boot, Page File, Crash Dump, Primary Partition).

My questions are:

(1) What are the difference between the three concepts "partition", "drive" reported by System Information and "volume" reported by Disk Management? They seem similar but not quite same. At least drives do not include SYSTEM_DRV, but partitions and volumes do.

(2) what is the volumn SYSTEM_DRV for? why it is not shown up in drives, only in partition and volumns?

Thanks and regards!

UPDATE:

(1) Report of System Information about drives:

Drive C:
Description Local Fixed Disk
Compressed No
File System NTFS
Size 221.95 GB (238,313,005,056 bytes)
Free Space 202.36 GB (217,280,110,592 bytes)
Volume Name Windows7_OS
Volume Serial Number CC3B4EF0

Drive E:
Description CD-ROM Disc

Drive Q:
Description Local Fixed Disk
Compressed No
File System NTFS
Size 9.77 GB (10,485,755,904 bytes)
Free Space 3.28 GB (3,519,356,928 bytes)
Volume Name Lenovo_Recovery
Volume Serial Number B63E336A

(2) A screen shot of my disk management
alt text

Best Answer

A hard drive is a physical device (disk). A partition and a volume are essentially the same thing: a logical structure on the physical disk for the file system. The system drive is where the OS boot files are located (Boot folder, bootmgr, etc.). The system drive doesn't show up in the hard drives because it's not a hard drive, it's a volume (partition).

Also, you'll notice in Disk Management that the hard drives are listed as Disk 0, Disk 1, etc. and the volume structure (layout) of each disk is listed to the right of each disk in the lower pane.

Related Solutions

Windows – Primary vs. Extended partitions

In the beginning there was the original IBM PC BIOS partition scheme, which allowed up to four partitions. The FAT16 file system as used by MSDOS 2.x and 3.x would only support a formatted volume of 32MB. When a PC hard disk was 20MB this wasn't an issue but the advent of much larger ESDI(1) disks in the mid 1980s drove an urgent need for a scheme that could support more partitions.

The key issue here is backward compatibility. Older BIOS and DOS versions only supported the four partition scheme, so a partitioning scheme that would not break older versions but could support more partitions was needed. The solution was to allow partitions to be further sliced up by setting up another partition table within that partition.

Thus, the 'extended' partition was born. Extended partitions are just a format for slicing up a partition into sub-partitions. It exists solely as a kludge to preserve backward compatibility with the old partition format.

ESDI stands for 'Enhanced Small Device Interface'. It was a refinement on the ST-506 interface that allowed more sectors on the disk, faster data transfer and also removed the artificial 1024 cylinder limit of the ST-506 interface. In 1982-3 a typical PC hard disk might have been about 20-30MB where you had one at all (they were quite expensive at the time). By 1986 you could purchase an ESDI hard disk with capacities up to about 330MB.

Linux – repair partition table

Not too tricky. Hopefully.

First of all, note the size and order of all your partitions on /dev/sda:

challenger:/home/michael # grep . /sys/block/sda/sda*/{start,size}
/sys/block/sda/sda1/start:63
/sys/block/sda/sda2/start:228690000
/sys/block/sda/sda3/start:257040
/sys/block/sda/sda1/size:256977
/sys/block/sda/sda2/size:83885760
/sys/block/sda/sda3/size:228432960

Run fdisk on /dev/sda and change the units to sectors:

Command (m for help): u
Changing display/entry units to sectors

Then start making partitions. Use the appropriate numbers start and size for each partition.
Avoid an off-by-one error - subtract one from size before typing it into fdisk.

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 1
First sector (63-312581807, default 63): 
Using default value 63
Last sector, +sectors or +size{K,M,G} (63-312581807, default 312581807): +256976

Command (m for help): p

Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders, total 312581808 sectors
Units = sectors of 1 * 512 = 512 bytes
Disk identifier: 0x02b002af

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1              63      257039      128488+  83  Linux

Don't forget to set your partition IDs and toggle the boot flag on the right partition

Now re-install your MBR and you should be ready to go.

Naturally you can do all this using your favorite partition editor... parted works just fine as well.

If you've lost the information regarding start/end of partitions - parted has 'rescue' options to search the disk for lost partitions. But you shouldn't need those.

Best Answer

Related Solutions

Windows – Primary vs. Extended partitions

Linux – repair partition table

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