Compressed CD/DVD image compatibility

[DenisF]

Hello,
Is it possible to add compressed CD/DVD image compatibility like ISZ, CSO, UIF or one open format?
Because CD/DVD image take a lot of space in physical disk.

Thanks

[stefan.becker]

No, not possible in VBOX directly. Maybe over a zipped partition with a driver on the os.

[DenisF]

It's the reason I post in Suggestions topic...
I think it's possible. We can mount zipped file.

[stefan.becker]

I think you are the frst asking for this.

Its cheaper for oracle to buy a bigger hard disk for you than to develop such a feature.

[mpack]

IMHO there are no widely accepted standards for compressed CD/DVD images, and anyway binary data often doesn't compress very well. Still, there's no reason why it couldn't support (say) .iso.gz.

Of course VBox already supports compressed .DMG (currently popular on Apple hosts, but probably no reason why this wouldn't work elsewhere).

[michaln]

Is it possible to add compressed CD/DVD image compatibility like ISZ, CSO, UIF or one open format?

Yes, and it's been done already. VirtualBox supports the Apple DMG format including compression for ISO images.

[DenisF]

Hello,

I found this open source compressed format:
http://pismotec.com/ciso/

[mpack]

Which tools output in that format?

[DenisF]

They have their own:
http://pismotec.com/ptiso/
I test it and save 1GiO on 7GiO DVD iso with compressed files inside.

[mpack]

I doubt that the devs will be interested in implementing support for a format produced by one obscure tool when they already have support for DMG.

[socratis]

when they already have support for DMG

Well, to be honest, that has some really big issues as well: https://www.virtualbox.org/ticket/16847

• Any DMG created from the Disk Utility will not mount. I believe I've tried all possible combinations, but they all fail with the above error message.
• Xcode 7.3.1, that's actually the weirdest. The VM (OSX) shows a "The disk you inserted was not readable by this computer. Ignore | Eject". If you copy the same exactly DMG in the VM, it is mounted and works as expected.

[DenisF]

And I found nothing to make dmg on windows or linux...

[mpack]

Perhaps so, but the format is at least backed by a recognizable source.

Ultimately it is for the devs to decide if they are interested, I simply voiced my guess - which still stands.

[DenisF]

Hello,

I've found a Microsoft format managed by open source software:
https://wimlib.net/
https://en.wikipedia.org/wiki/Windows_Imaging_Format
Is it a recognizable source?

[mpack]

Microsoft flies lots of kites. I would want to see evidence of actual widespread use before it interested me. Given that they've been flying this particular kite with no great conviction since the Vista era I don't think anyone is predicting a big uptick in use now.

Thinking about it, what's the need? If you resent the space occupied by ISO files then why not store them in a compressed folder, and/or a secondary drive?

p.s. Just been reading some of the background material: I'm not even convinced this is a disk image format at all, never mind a CD image format. It seems to be being compared to formats in the file archiver class such as ZIP and RAR. ZIP is used to copy files, it cannot to be used to image disks, it can however be used to compress an ISO and that has already been suggested in this discussion.