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I'm looking for a meaning of the output of the fdisk command on centos , because it is a little different from other system , because other systems uses sectors ,but here the size can be determined by the cylinders !

so i wanted to create a new partition on a second SCSI HDD , here is the petition table for that disk:

Disk /dev/sdb: 1073 MB, 1073741824 bytes
255 heads, 63 sectors/track, 130 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: 0xe372eab9

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1          14      111430+  83  Linux
/dev/sdb2              14          15        8032+  83  Linux

so my question are as follows : 1 - it shows that the head number is 255 , is this fake number since I'm using Vmware?

2- the number "16065 " is the number of blocks ,bytes or sectors ?

3- is the block size in my case is 512 or 1024 ?

4- what does the values in the blocks , id and system mean ?

5- why there is a "+" in the values of the blocks column ?

I know there is a lot of questions ,but please provide me with as much of info as you can.

Note: I know all about the physical formatting of the hard disk : sectors ,tracks ,clusters and cylinders , but the output got me confused .

thanks in advanced

1 Answer 1

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1 - it shows that the head number is 255 , is this fake number since I'm using Vmware?

No modern disk uses head and cylinder addressing. It's fake.

2- the number "16065 " is the number of blocks ,bytes or sectors ?

It says "16065*512 bytes".

3- is the block size in my case is 512 or 1024 ?

The start and end values are cylinders of 8225280 bytes, or about 8MB. Note that the number is approximate, since partitions don't have to start on cylinder boundaries. This allows you to estimate the block size to be 1K.

4- what does the values in the blocks , id and system mean ?

Size in 1k-blocks. ID indicates the type of data supposed to be in a partition, and "system" is the symbolic name for the ID. "Linux" and 83 (a hex number) mean "Linux filesystem". But I don't know if any application makes use of this.

5- why there is a "+" in the values of the blocks column ?

I pass.

Centos also has parted, with possibly better reporting of addresses and sizes.

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