Disk backup with dd

This post describes how to create an image of a whole disk with dd. I use this to backup my Mac OS X system disk before a major change, for example upgrading from Snow Leopard to Lion. Since I see such operations as risky (not running on Apple hardware), I want to be able to go back to a working state easily.

This process is not limited to Mac OS X, you can follow this guide to create a disk image of whatever disk you want: your windows OS disk, your data, anything.

Here are the steps I am going to go through in this post:

• start up in linux,
• find the device name of the disk to backup,
• find the mounted name of the disk where to save the backup,
• run the dd command with the appropriate attributes,
• test that the backup worked.

Installing Mac OS X

Installing OS X on a non-apple hardware is easier than it sounds, as long as the hardware is compatible.

Method at tonymacx86

Tonymacx86 provides a standard method for installing Mac OS X on a Sandy Bridge system. This method worked fine for basic funtionality, and only a few more tweaks were needed for sound and network to work.
What you need besides the computer is:

•  a blank CD, for iBoot and Multibeast
•  an OS disk purchased from Apple

The method makes it very important not to restart after updating to 10.6.8. That is precisely where my computer crashed, so I had no choice but to restart anyway. That did not seem to cause any problem, though.

From the Multibeast installer, you are presented with two options: EasyBeast and UserDSDT.