mount -o loop,ro,noatime cdrom_image.iso mountpoint/
mount -o loop,ro,noatime partition_image.img mountpoint/

##</code><code>##

( Description of MSDOS-style partition table and master boot record as gleaned
from the soure of /parted/ and /grub/.  )
---------------------------------------------------------------- 0 - 63
boot code boot code boot code boot code boot code boot code 
---------------------------------------------------------------- 64 - 127
boot code boot code boot code boot code boot code boot code 
---------------------------------------------------------------- 128 - 191
boot code boot code boot code boot code boot code boot code 
---------------------------------------------------------------- 192 - 255
boot code boot code boot code boot code boot code boot code 
---------------------------------------------------------------- 256 - 319
boot code boot code boot code boot code boot code boot code 
---------------------------------------------------------------- 320 - 383
boot code boot code boot code boot code boot code boot code 
---------------------------------------------------------------- 384 - 447
boot code boot code boot code boot code (to 440)        AAAABB(
---------------------------------------------------------------- 448 - 511
partion one  )(partion two   )(partion three )(partion four  )CC

AAAA = mbr_sig
BB = unknown 
CC = magic

Each 16 byte partion entry is 
---------------- 0 - 15
ABBBCDDDEEEEFFFF
C = type
BBB,DDD = 
EEEE = start sector from 0
FFFF = length in sectors

##</code><code>##

mount -o ro,noatime,loop,offset=<sector offset * 512> hard_drive_image.img mountpoint/