Table of Contents
Disk image on OSX
Backup and restore a disk image
Look in terminal the disk added
# mount /dev/disk0s2 on / (hfs, local, journaled) devfs on /dev (devfs, local, nobrowse) map -hosts on /net (autofs, nosuid, automounted, nobrowse) map auto_home on /home (autofs, automounted, nobrowse) /dev/disk1s1 on /Volumes/kernel (msdos, local, nodev, nosuid, noowners)
How is it partitioned
# ls /dev/disk1* disk1 disk1s1 disk1s2 disk1s3 disk1s4
You can keep a copy of the actual content
# dd if=/dev/disk1 of=/tmp/myBackup 3862528+0 records in 3862528+0 records out 1977614336 bytes transferred in 592.626715 secs (3337032 bytes/sec)
Or restore an image
# dd if=/tmp/myBackup of=/dev/disk1
Problems
During a Restore a disk image you can get such error Resource busy
# dd if=/tmp/myBackup of=/dev/disk1 dd: /dev/disk1: Resource busy
If you try to unmount it, you will get the same error: Resource busy
# umount /Volumes/kernel/ umount(/Volumes/kernel): Resource busy -- try 'diskutil unmount'
And if you try again, you will obtain a novel error: Operation not supported
# dd if=/tmp/myBackup of=/dev/disk1 dd: /dev/disk1: Operation not supported
At this time, The /dev/disk1 is not present anymore. So, unplug and replug the card.
Again, if you try to to restore the file, you obtain:
# dd if=/tmp/myBackup of=/dev/disk1 dd: /dev/disk1: Resource busy
Open the Disk Utility application (/Applications/Utilities/Disk Utility.app), and on your Disk drive, unmount any of it's partitions.
Then you will be able to restore an image
# dd if=/tmp/myBackup of=/dev/disk1 3862528+0 records in 3862528+0 records out 1977614336 bytes transferred in 592.626715 secs (3337032 bytes/sec)
During the restore process, you can check the status.
# pgrep -l '^dd$' 10472 dd
# kill -SIGINFO 10472 244697+0 records in 244696+0 records out 125284352 bytes transferred in 97.953448 secs (1279019 bytes/sec)
If you have a zipped image to restore, you can do
# unzip -p /tmp/myBackup.img.zip | dd of=/dev/disk1