I've just saved the restore for Windows 8.1 onto a USB stick; now, I've been creating the low level copy of it on my HDD, by executing the following command:
sudo dd if=/dev/sdf of=/disk2/Archive/windows8.1-restore.img bs=4M oflag=direct
I wanted to double check that my 'dd' command was ok, so I've rerun it two times, specifying both
bs=16M; I've checked the size and it's exactly the same, but md5sum gives a different output for the three files:
c38a2b07b3d473d3f1876331edc2647b windows8.1-restore.img.4M 568e382844431eef63d4ba6dc4c2c5ac windows8.1-restore.img.8M 568e382844431eef63d4ba6dc4c2c5ac windows8.1-restore.img.16M
I believe I have unmounted the USB stick the second and third time.
Should I be worried about anything?
Total file size is
31024349184 bytes in all cases, my understanding of
bs=xxx is to just control the speed in case one wants to dump the whole USB sitck/drive.