Create hd image with dd

on
dd if=/dev/sda of=image/sda_full.img bs=64k
 244353+1 records in
 244353+1 records out
 16013942784 bytes (16 GB) copied, 577.159 s, 27.7 MB/s

Now what’s in that file:

file sda_full.img

results in my case in

sda_full_3_20120919.img: x86 boot sector; 
partition 1: ID=0x83, active, starthead 32, startsector 2048, 29870080 sectors; 
partition 2: ID=0x5, starthead 254, startsector 29874174, 1402882 sectors, code offset 0x63

This tells me /dev/sda contains 2 partitions.

Now I want tho mount the first partition, starting at sector 2048

now the offset of this partition must be calculated: 512 * 2048 = 1048576

Mounting is now be done by

sudo mount -o loop,offset=1048576 sda_full.img /tmp/tmp_mount

restore on other computer:

sudo  dd if=image/sda_full.img of=/dev/sda bs=64k
 244353+1 records in
 244353+1 records out
 16013942784 bytes (16 GB) copied, 523.89 s, 30.6 MB/s