Thomas There's no such thing as a "compressed" .dmg image. Not, at least, in this context. A disk image is just like an .iso image used in other operating systems. Neither is compressed. The files are exactly as they would be if you were to open a folder. That is how you're able to mount the image without the need for decompression utilities.
I would suggest that if you have an installdvd.dmg on your desktop, it's most likely Lion. The Mountain Lion disk image is indeed 4.35 GB which is too large for a single-layer DVD. Apple is moving away from physical media boot systems in favour of either USB thumb drives or Internet-based operating system downloads. For example, if you boot the new Mac Minis and have a blank hard drive, there's a firmware-based recovery assistant which allows you to download the operating system via the Internet subject to a valid Apple ID and hardware verification. Apple is also now much more strictly validating hardware in your machines. For instance, if you have a non-Apple authorised memory module or two in your machine, even if they meet the technical specifications which Apple uses precisely, the hardware validation can fail and you won't be able to download the operating system via the recovery mechanism. The same is true if you change the hard drive in your machine and or use SDD media in its place. The media has to be validated and authorised by Apple otherwise the recovery process can fail. This is something which most people are probably not aware of, but all the same it is now true. So, for instance, the "Lion Disk Maker" which Sarah has recently discussed is now obsolete, as I also said in a recent reply to Sarah's message. You can no longer create a DVD of the operating system, as the disk image contents in the package are too large. This is no accident. Apple really is squeezing the process tightly now, so be mindful of this if you ever want to change your hardware configuration. To be honest, I really find Apple's policies of hardware validation disgusting. They are effectively telling their customers that, if they want to upgrade memory or hard drives, they must do so using Apple-authorised components, paying Apple's massively inflated prices. Now, all that having been said, our machines do have hardware in them which we didn't purchase from Apple. I performed memory upgrades on 8 of our 9 Mac Minis. They all now have 8GB of RAM which I bought in bulk earlier this year from Crucial. That memory seems to satisfy the validation process. What I talk about above is information which I was given by an apple employee. It is no secret, they are trying to squeeze out the competition. Gordon On 28 Jul 2012, at 01:42, Thomas McMahan <[email protected]> wrote: I haven't either, but it's interesting that yours said 4.35 and mine says 4.18 and mine is uncompressed as well, just the installESD.dmg It's just sitting there on my desktop at the moment so it's easily found when I have something to put it on as a backup. <--- Mac Access At Mac Access Dot Net ---> To reply to this post, please address your message to [email protected] You can find an archive of all messages posted to the Mac-Access forum at either the list's own dedicated web archive: <http://mail.tft-bbs.co.uk/pipermail/mac-access/index.html> or at the public Mail Archive: <http://www.mail-archive.com/[email protected]/>. Subscribe to the list's RSS feed from: <http://www.mail-archive.com/[email protected]/maillist.xml> The Mac-Access mailing list is guaranteed malware, spyware, Trojan, virus and worm-free! Please remember to update your membership options periodically by visiting the list website at: <http://mail.tft-bbs.co.uk/mailman/listinfo/mac-access/options/>
