OS X: How to backup the Mac OS X Install DVD?
October 5, 2010 1 Comment
And so I discovered the intricacies of the Apple hybrid disks…
My first choice was to use the standard Disk Utility application. Obviously it recognised the disk and reported it as a 6.74 GB volume, formatted as Mac OS Extended (HFS+).
It even allowed me to create a Disk Image from the content of this disk (Disk Utility Menu -> File -> New -> Disk Image from “Mac OS X Install DVD”, resulting a .cdr file, described as a “DVD/CD master”).
To my big surprise, I plugged the same Mac OS X disk into a Windows machine, and it showed a completely different picture:
The ISO part not only provides divers for the Boot Camp Windows partition, but also allows to remotely install DVD-less devices like the MacBook Air, in a network where there are no other Mac OS X computers. For this, run the Setup.exe on a Windows machine and you’ll installs a special DVD sharing server. While booting the MacBook Air, if a special key is pressed, the network boot mode is selected, and a list of shared DVDs is displayed for selection. (On Mac OS X, this functionality is provided by the Remote Install Mac OS X application).
Once I understood the hybrid nature of the Apple Install DVD, I also understood that regular Windows or Mac tools will probably not be able to backup both parts of the disk; Apple Disk Utility offered to create a “DVD/CD master” of the Mac part, while the Windows tools are able to create a ISO file with the Windows part.
Further research revealed that a possible solution to backup the Mac Install DVD is the Disk Copy function from the (quite extensive) package Roxio Toast 10 Titanium.
This time the DVD was reported to be a 7.24 GB volume, the sum of the Mac and Windows parts. From this window it is possible to either directly create a DVD DL, or to save the content as a Disk Image, using Roxio’s custom .toast format, that can be later burned to disk.
Although initially confusing and frustrating by it’s dual appearance, the Apple Mac OS X Install DVD is in fact a quite interesting design, packing two disks into a single hybrid one. It’s nothing magic, and can be copied with existing tools, like Roxio Toast.
Critics? Well, if I would not expect Windows DVD tools to recognise the Mac part, I would expect the Mac OS Disk Utilities to be able to mount, or at least to report the existence of the Windows part, and properly duplicate the entire disk.