Apple MACOSX .DMG format?

[LuckMan212]

Hello I look for months for a program to burn .DMG files on my WinXP machine. I can find no such tool.

 

I have tried

 

Nero7

Alcohol 120

CDBurnerXP

burnatonce 0.99a

ImgBurn 1.0.0

 

etc..

 

I was really hoping now that ImgBurn sole purpose is burning images.. maybe LightningUK! can add support for these .dmg files? it would really make this program truly unique.. please!

[LIGHTNING UK!]

I know nothing about the DMG files.

 

Could you make one with a simple text file or something in it and send it to me for inspection?

[LuckMan212]

sorry for the delay, didnt know you had replied (for some reason i did not get the email notification)

anyway yes here are 2 sample DMG's I created on my MacOS X 10.4 box. They are both basically empty, with just a single "readme" text document in each. The first is 550kb which is the minimum size allowed for DMG apparently, and the other is 2.5mb, for comparison. I can create larger ones if you need.

 

Also, you may want to glance at the dmg2iso utility (now quite obsolete) to get more background info on this format, which seems to be quite similar to ISO.

 

thanks I really appreciate this!!

 

the files:

550kb .dmg (sample 1)

2.5mb .dmg (sample 2)

[LuckMan212]

i dont have a DVD burner on my Mac... i found a really roundabout way of burning DMG images on my PC:

 

1) download DMG on PC

2) transfer via ethernet the DMG file to my Mac (takes looong time for a dvd image!)

3) open the image in apple "Disk Utility"

4) choose "convert..." and select "DVD master" as the output format

5) this process takes about 10-15 minutes and will produce a .CDR file

6) transfer this .CDR file back over the network to the PC

7) rename the .CDR file to .ISO

8) burn with Nero 7

 

This method seems to work except there are 2 main problems

 

1) it takes FOREVER!

2) the burned DVD is no longer "bootable" even though the files are there...

 

So, LUK if you have any success in being able to burn the .DMG unharmed directly from the PC i think it would be so helpful!! I cross my fingers....

[LIGHTNING UK!]

By the looks of things, the DMG format is a compressed image containing multiple partitions etc.

 

To be honest, that's too much of a pain in the butt to get around on-the-fly (at the moment at least).

[LuckMan212]

ok I hear you..

 

well what about maybe supporting "certain" DMG formats such as those with only a single partition? this would work for 99% of the DMGs I have seen out in the wild, and would be most useful

 

well, if you feel ambitious...

[LIGHTNING UK!]

Ok, maybe basic ones.... but no promises

[LIGHTNING UK!]

Sorry, I looked at the files you posted and that dmg util doesnt work with them.

 

If only I had the code to Apples hdiutil program!

[LuckMan212]

Well Apple has the Darwin project which is an open-source version of their operating system. I believe the code you need is probably contained in that project? Perhaps in isoutil-32 branch..? I don't know I thought maybe worth a try...

 

http://www.opensource.apple.com/darwinsource/10.4.3/

[LIGHTNING UK!]

No luck with that but I have found something else.

 

Any chance you could convert those 2 files to their ISO equivalents using the hdiutil program and then post them up too?

 

I can read the parition map ok now and locate the start of the disc image partition, next I need to know exactly what has to go into the resulting ISO file - and hence burnt to disc!

 

If you just burn the entire thing, that's pretty simple! The DMG's you've sent me are just ISO images but have a sector size of 512 instead of 2048. So I just have to expand 512 -> 2048 (I think )

[LuckMan212]

Hey LUK thanks for your continued efforts on this project... I have done as you asked and converted those 2 image files using:

 

hdiutil convert sample1.dmg -format UDTO -o sample1.iso

 

I have uploaded these files:

sample1.iso

sample2.iso

 

I hope these are sufficient for you, please let me know if you need more samples...

thanks so much

[LIGHTNING UK!]

Hmm there's hardly any difference between the two! (DMG and ISO I mean)

 

You can't do it in ImgBurn at the moment, but have you tried burning the DMG file in Nero without any sort of conversion? (Maybe just a simple rename to *.ISO)

 

When it asks you for the foreign file format, just select MODE 1, 2048.

[LuckMan212]

No I have not tried that, but didnt you say the DMGs had a sector size of 512? so woulndt burning them using 2048 cause a problem? well anyway I imagine that more differences in the format might appear if I added more files to the filesystem of the DMG and created a larger one... also what about the compression you mentioned, DMG being a compressed format and ISO being uncompressed?

 

if you want I can create, perhaps a 20mb DMG with some nested files and folders.

[LIGHTNING UK!]

Yeah they do but it's probably down to the cdrom to read them at that size. I kinda assumed going DMG to ISO would put 512 in 2048 but that's not the case. The ISOs you gave me still have data in the exact same places... ie. 4 x 512 bytes in a 'normal' 2048 byte sector.

 

It looks to me as if the OS itself must handle sector sizes and decompressing the files on the fly (unless Macs use weird drives that support reading 512 byte sectors).

 

Is there no virtual drive type tool you can use to mount these DMG files? Maybe this could show us if the generic cd/dvd rom driver can understand what's in the image - compressed or uncompressed.

 

I don't think I've got much chance of uncompressing the image, and I did say I'd only think about adding support for 'Basic' images

[LuckMan212]

hey this is an interesting idea!!

 

so here's what I did:

 

I had a few DMGs lying on my hard drive. I installed Mediafour's MacDrive 6.08 product (full version, not demo) and rebooted. Then I used Daemon Tools 347 to mount the .DMG and lo and behold, i could see the disc mounted properly and even all the files were there! I tried a few other images, including some very large (3+gb) images, and they seemed to work OK.

 

Problem was, there were some DMGs I could not mount at all (mostly the smaller ones-- I guess maybe those were compressed??) I copied them to my Mac and mounted them and they verified fine so I know the DMGs are OK -- it must be certain types of DMG that are nonstandard.

 

OK so news gets worse... I tried to actually copy some large files from one of the mounted DMGs to my desktop and it got like 80-90% through the copy and then reported "cannot read from file - parameter is incorrect" or something like that. I tried also using Alcohol120% virtual CD driver -- same error.

 

So ... hmmm! seems like it can almost work but this Mysterious DMG format is quite troublesome. Well I wish there was some better documentation on it so we can have a more peaceful cross platform environment but I guess I dream too much...

 

Also one last thing in my testing I discovered something-- Daemon tools virtual driver is MUCH MUCH faster than Alcohol.. maybe 2-3x faster. I noticed this when copying those large 600+mb files. Just something I never knew...

[LuckMan212]

oh hey also I just found something very interesting

I am going to test this and report back...

 

from a shareware company called Acute Systems:

 

They have product called TransMac which has new version 7.2, here is an excerpt from the features:

 

"- Support for opening compressed Mac .dmg (disk image) files.

- Support for writing compressed Mac .dmg (disk image) files to CD/DVD/disk. "

 

very interesting indeed!!

maybe the developer can share his secret??

well anyway I will test.....

[LIGHTNING UK!]

All DT is doing is loading it as a standard ISO image.

 

So it looks like burning as Mode 1, 2048 will work.

 

The rest is down to that MacDrive program. Perhaps it's not perfect!

 

Try burning properly using Nero and the method I mentioned earlier and then put that disc in your Mac. Use an RW or something if you're short of discs

[LuckMan212]

just wanted to update this thread with the following information:

 

burning DMGs using Nero as Mode1/2048 does not work, at least not for me. I get coasters.

 

The TransMac software I mentioned above does work however. I wound up buying the program because this is something I do quite often.

 

I am not sure how the developer figured out how to decode those compressed DMG files but so far it has worked on every DMG I have tried. maybe someday LUK will be able to add this capability to ImgBurn, but at least now there is a working solution

[spinningwheel]

Thanks for the follow up LuckMan212

[Dubstar]

just wanted to update this thread with the following information:

 

burning DMGs using Nero as Mode1/2048 does not work, at least not for me. I get coasters.

 

The TransMac software I mentioned above does work however. I wound up buying the program because this is something I do quite often.

 

I am not sure how the developer figured out how to decode those compressed DMG files but so far it has worked on every DMG I have tried. maybe someday LUK will be able to add this capability to ImgBurn, but at least now there is a working solution

 

 

Anychance you can contact me by email to talk me through how you got this to write a bootable mac CD? as transmac just seems to be spitting out empty CDs for me

[DudeBoyz]

It would be cool if we could convert / burn .dmg and other mac formats with ImgBurn. I also have a Mac with OS X 10.4.x and have to use Toast 7. I don't like that app very much, and would prefer to copy the DMG file over to my PC and use my BenQ 1620 to burn it instead of the built-in sony drive on the mac.

 

Anyways...

 

Thanks