Disk Utility File Too Big for CD

Discussion in 'Mac Apps and Mac App Store' started by gvdv, Oct 19, 2009.

  1. gvdv macrumors regular

    Feb 18, 2007
    I hope that this is the right place to post this.

    I am fairly new to the Mac world. The other day I was trying to do a disc copy of a music CD. I followed the instructions within Disk Utility, which resulted in a .dmg (disk image) file being created.

    However, when I went to burn the resulting file to a blank CD I found that the file was bigger than the capacity of the CD. Obviously, the disk image file itself takes extra space (in addition to the size of the original music files).

    Is there any other way of creating a 'snapshot' of a CD or DVD? Perhaps 'on the fly', as I do with my PC's?

  2. Steve-M macrumors regular

    Jun 12, 2009
  3. gvdv thread starter macrumors regular

    Feb 18, 2007
    Hi Steve-M,
    Thanks very much for this.

    I am unfamiliar with how one goes to Terminal and/or goes to the place to input a command of the sort mentioned in the link you posted, so could you please give me some more information about this?

    Also, I presume that it is not possible to make a CD or DVD on the fly as it is in the PC world, which is a shame because creating an ISO or image file of any sort is a slower way of doing things when making a single copy.

    Thanks once again, and I look forward to further clarification.

    All the best,

  4. Steve-M macrumors regular

    Jun 12, 2009
    Sure, first thing to do is to put the CD or DVD you wish to copy into your drive. Once it is mounted, it will appear on your desktop. Make note of the name of the disk as it appears on your desktop.

    Next go to Applications, Utilities, and open the Terminal app. Once the terminal is open, you are ready to input the command to make a ISO of your CD or DVD.

    So with the terminal opened, type hdiutil makehybrid -o newname /Volumes/ now type the first two letters of the name of the disk you are copying, and hit the TAB key. The terminal will fill in the rest of the name for you. You can find the name of the disk your copying by looking on your desktop where it is mounted. So if the name of your disk is Disk001, then your code would be hdiutil makehybrid -o newname /Volumes/Disk001. After you have done all that just hit your ENTER key, and the terminal will begin making the ISO, which will be saved in your home directory. In the example given above, the ISO being created will be named newname. You can change newname to anything you wish while entering the code.

    Now after your ISO is created, there are several things you can do with it. You can mount (or open) the file by double clicking, view the contents, drag the contents to your desktop, install software from it if there is any, and you can burn it to disk by using the Disk Utility app.

    Basically, if you make a disk image (which is what a ISO file is) of a CD or DVD, and then mount it, to your Mac it is the same as if you put the original disk into your drive, and was using it from there.

    Going a little further, you can also control click (control key + click combination) the disk while it is mounted on your desktop, and select Duplicate. Or if you have a audio CD mounted, you can import it into iTunes and burn a new copy from there. Or you can open a audio CD and drag each track to your desktop, and it will be saved as a AIFF file. Think MP3 but not compressed.

    Now if your coming from windows and are used to one application doing all your disk burning and copying, there is a free app for your Mac named Burn, which does this, and will take care of most your burning needs.

    I encourage you to learn all that you can about terminal commands, you will have a more powerful system at your disposal when you do.

    Happy burning, copying, saving stuff :)
  5. windels macrumors regular


    Oct 12, 2008
    I just want to mention the following, if your goal is to copy a music cd, and be playable as a music cd, ( meaning, not burned as mp3 or AAC ...) , than you can do this in Itunes. import it , than make a playlist. put those songs from your cd into the playlist and press: burn cd , in the bottom right corner. select burn as audio cd if you want it to be playable in a normal/ old fashion cd player.
  6. gvdv thread starter macrumors regular

    Feb 18, 2007
    Hi Steve-M and windells,
    Steve-M, many, many thanks for taking the time to be so conscientious in replying. Your message was also very clear and helpful, too.

    I will follow your suggestion of finding out about the Terminal commands; it sounds like the Terminal app provides one with the kind of flexibility and power (and ability to 'get under the hood') that DOS commands used to (and to an extent still do) in Windows.

    I will also follow up on the Burn app., too. I had used the 'Duplicate' command in Disk Utility to try to make a copy of the disc, and that's how I had got into the predicament I mentioned above, so Burn might be more to my advantage.

    windells, thanks for your reply, too. The reason that I didn't go the iTunes route initially is the same reason that I don't copy songs individually in the Windows world - sometimes discs which have segues between songs get 'chopped up' when copying them individually, i.e. a couple of seconds of silence are inserted because the app. 'sees' the songs as separate, discreet units, rather than being able to see the disc as a whole.

    A good example of this is The Beatles' 'Abbey Road', where there are continuous pieces of music between tracks.

    I will, however, try iTunes (much as I can't stand it as an app.) and see if I have any success.

    I think, though, that as Steve-M said, the app. he mentioned called 'Burn' might suit me more.
  7. gvdv thread starter macrumors regular

    Feb 18, 2007
    Downloaded and installed the 'Burn' app., and it is giving me exactly the same information that trying to Duplicate in Disk Utility did, viz., that the audio CD I am trying to copy is 744.7 (it sometimes says .8) MB.

    And yet, I can easily copy this disc in Windows where each track is reading as just over 2 MB's in size. I have a feeling that this is some kind of standardized number that Windows gives because it can't read the disc as a whole, but it is obviously under 700 MB's in size as I have copied the disc on many occasions.
  8. Steve-M macrumors regular

    Jun 12, 2009
    It wouldn't surprise me if the disk is 744.7 MB in size. The tracks on audio CD's are not compressed. Typically you can only fit 15 to 17 songs on a CD before it becomes full. I have Boston Greatest Hits loaded in my superdrive as I'm typing this. It has 16 songs and Finder is reporting it to be 761.8 MB in size.

    I still think creating a ISO is your best bet. Interestingly enough, when you copy a audio CD using your favorite windows burning program, it will first create a disk image of the original CD, before burning the copy. You may not see it because it is normally stored in a temp folder, and then deleted after the burn is successful, but it is there temporarily. The only exception would be if you had two drives installed in your system that where capable of doing a direct burn from one drive to the other.

    Mac's are a different story. By design you burn audio CD's in iTunes, movies in iDVD, and data disc in Finder. It takes a bit of getting used to coming from windows, but over time you will began to see the logic behind it.

    <!-- begin subliminal message --> ISO ISO ISO ISO ISO <!-- end subliminal message --> ;)
  9. gvdv thread starter macrumors regular

    Feb 18, 2007
    Hi Steve-M,
    Thanks for continuing the dialogue (and my Mac 'education' :)).

    I will actually try the method you suggest tomorrow, but I don't have very much confidence that I'll have any success in fitting 744 MB onto discs which can only accommodate 700 MB's. (Does the ISO get compressed? Is that why you think I might be successful in burning a file of that size to a CD?).

    It's interesting to me that this figure is exactly the same one as when I tried the original method of creating a CD; hence my pessimism about the ISO method working.

    Yes, the 'on the fly'/virtual method that Windows uses is the same kind of process, but it obviously creates file sizes which are smaller.

    Thanks, once again,
  10. Steve-M macrumors regular

    Jun 12, 2009
    gvdv I have made a big mistake here. You are right, it is not possible to burn a 744 MB iso to a 700 MB CD-R. My apologies for overlooking this, Hope you read this before you make a coaster. Looks like we have two very large CD's here. I just checked another audio CD with 12 songs and it is only 484 MB.

    I am however very curious how you where able to copy this CD in windows. I'm confused :confused:
  11. gvdv thread starter macrumors regular

    Feb 18, 2007
    Hi Steve-M,
    Thanks for the message; in a way it clears up something I was puzzling over.

    I probably wasn't clear in my earlier messages, but hopefully this will answer your question.

    The reason I was puzzling over what you had said was that the audio disc(s) I was trying to copy were all a maximum of 700 MB (actually under that); I couldn't work out why, when I made the .dmg image file they appeared to be 744 MB, when in Windows they weren't that big (hence being able to make a simple disc copy in Windows).

    I would imagine that what is happening in OSX is that the .dmg file adds extra MB's to the file size (i.e., the original data containing the music is recorded, as well as extra data containing the .dmg information).

    This still leaves me with the question, is it possible in OSX to make a simple 'on the fly' disc copy of an audio disc, as it is possible to do in Windows? So far, the answer seems to be 'no'. The appeal of making a disc copy is that it is a 'snapshot' of the disc, i.e., an exact copy which preserves whatever 'formatting' (such as low volume segues) which might exist on the original disc, such as the little pieces of music found between tracks on such albums as 'Abbey Road'.

    I did notice that iTunes has the option to vary the length of silence between tracks, or to eliminate it all together, but I have yet to test whether or not it can preserve the 'formatting' described above exactly.

    All the best,
  12. kloopt macrumors newbie

    Apr 23, 2010

    I'm having the same problem running 10.6.3 on a Macbook Pro 5,5.

    The original audio disc is a Sony 700 MB CD-R.
    Finder info tells me the original disc is 762 MB.
    iTunes tells me it's 726.7 MB.

    I was able to make a .dmg (If I remember correctly, I dragged and dropped the AIFF files from the original CD to a folder on my desktop, then created the image-- I think with Disk Utility).
    Anyways, according to Finder, the .dmg copy is 735.1 MB.

    When I still couldn't burn this to my blank CD (Sony CD-R Audio 80 Min), I made an .iso using the "hdiutil makehybrid" command in Terminal.
    Finder tells me this .iso file is 763.3 MB. Again, no go.

    I downloaded Burn and it's telling me there is not enough space to burn a copy onto my CD-R.

    I ultimately imported to iTunes and then burned using iTunes, but this is not an acceptable solution in my eyes.

    Why can't I make a direct copy of this disc?
    Was my original disc created in some sort of magical fairy land?

    I shouldn't have to convert AIFF files to MP3 just to copy an audio CD.
    Doesn't this conversion sacrifice fidelity anyway?

    I guess my questions are:
    1. Have you solved this problem?
    1. How did my friend burn this CD in the first place?
    2. What in the world is going on?

    Thank you for your time and any assistance you can offer.

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