Can you covert multiple .dmg files into an ISO?

Discussion in 'Mac Apps and Mac App Store' started by techster82, Feb 6, 2006.

  1. techster82 macrumors member

    Jan 21, 2006
    I have been researching google and the forums trying to answer my question but can't get a straight answer.

    I have a backup of one of my mac programs that is a collection of what I believe are .dmg files. I had them as a large rar file with the many files inside. What I am trying to do is convert the many .dmg files into one that can be recognized by the mac, preferably an .iso or something that will boot. Has anybody had this problem? What seems to be the solution.
  2. mrichmon macrumors 6502a

    Jun 17, 2003
    The easy way is to mount all of the .dmg files then drag each of the files in the .dmg files into Toast to create a new image.

    Alternatively you can use DiskUtility to create an empty .dmg image that is large enough to hold all of the contents of the multiple .dmg files. Then mount the empty image and mount the .dmg files and drag the contents of the .dmg files into the mounted empty .dmg file.
  3. techster82 thread starter macrumors member

    Jan 21, 2006
    Thanks very much for your reply. I don't have toast so I can't try that, but I do have nero on my pc. If I transfer the .dmg files to the pc then burn it with nero as an ISO would that work? Also, what do you mean by mounting?
  4. mrichmon macrumors 6502a

    Jun 17, 2003
    No. The problem is that you will not be able to mount the .dmg files under windows. So instead, use DiskUtility to create a .dmg that is 750MB in size and copy the contents of each of your small .dmg images over into the .dmg that you create from DiskUtility.
  5. techster82 thread starter macrumors member

    Jan 21, 2006
    I created what I see as a disk image with disk utility. I made an 8gb size because the total size of my dmg files is almost 7gb. I dragged them all over, and now when I open the image it is just the list of files. I am totally lost right now.
  6. mrichmon macrumors 6502a

    Jun 17, 2003
    As I stated originally, you need to mount each of your .dmg files and then copy the files that are stored in the .dmg file over to the new .dmg file. It sounds like you have just copied over the .dmg files.
  7. techster82 thread starter macrumors member

    Jan 21, 2006
    yeah, thats what i did. I am playing around with the disk utility now trying to figure out this whole mount thing. I appreciate your patience, this is my first mac, and I am trying to do everything I do on my pc. My pc I know like the back of my hand. Mac is a little different.
  8. rspeaker macrumors 6502

    Jan 1, 2006
    You'll get used to it. And your life will be all-the-better for doing so.
  9. mrichmon macrumors 6502a

    Jun 17, 2003
    Maybe this explaination will help. (Warning: long post.)

    Under Windows (and MS-DOS before it) each drive is assigned a unique letter to identify the drive. 'C', 'D', etc. with 'A' and 'B' traditionaly reserved for floppy drives. To access a file on Windows you need to know both the drive letter and the path of the file on that drive. For example, C:\folderA\folderB\somefile.txt, that is drive 'C' and path \folderA\folderB\.

    Using the Windows GUI the distinction between drive letters and paths is blurred but under MS-DOS (and using the command line in modern Windows) you need to perform two operations to access a file. First you need to select the appropriate drive by entering the drive letter followed by a ':' (eg 'C:'). Second, you cd to the appropriate directory (eg cd \folderA\folderB). It is true that you can omit the disk selection step if the file you need to find is on the currently selected drive, but ultimately there are two separate concepts.

    Under Unix systems, including OS X, there was a desire to simplify these concepts. Rather than dealing with drives and paths the decision was made to eliminate the need to specify a drive location. The way this works is that you have a single "root" filesystem on a given drive. This drive is typically the boot volume for the computer under OS X.

    The boot volume has a bunch of folders stored on it. The top level folder is called '/' which is also known as the root of the filesystem. Just below the root are the 'Applications', 'Library', and 'System' folders along with various other folders including several hidden folders and files.

    When we want to add a new drive to a Unix system instead of allocating a drive letter as happens in Windows, a folder is created in the root filesystem. The system is then configured so that the filesystem on the new drive can be accessed as though the filesystem on the new drive is contained within the folder. The process of making the filesystem available through this folder is called "mounting" a filesystem or disk.

    Under OS X, one of the hidden folders in the root volume is named 'Volumes'. When you insert a CD (or connect an external drive) OS X inspects the name of the CD and creates a folder in the /Volumes folder using the name of the CD and then mounts the CD under this folder. When you drag the CD image to the trashcan OS X unmounts the CD and then removes the folder it created.

    For example, when my CD drive is empty then the /Volumes folder has nothing inside it. If insert a CD named 'Turbo Tax' into the CD drive, OS X creates the folder /Volumes/TurboTax and then mounts the CD under this folder. OS X will also display an icon for the CD on the desktop and in the left panel of a finder window. When you eject the CD, the icon is removed from the desktop/finder, the filesystem is unmounted and then the folder is removed from /Volumes.

    A .dmg file is an image of a filesystem. That is, a .dmg file can be thought of as a virtual CD. When you double click on the .dmg file OS X treats the .dmg file as if it was a virtual CD that you have inserted into a virtual CD drive. The .dmg file is inspected to get the filesystem name and then a folder is created in /Volumes and the filesystem is mounted under the new folder. When you eject the mounted filesystem, OS X unmounts the filesystem and removes the folder in /Volumes.

    Many .dmg files are read-only. However, it is possible to create .dmg files that are empty (using DiskUtility) and then copy files into the filesystem stored in the .dmg file.

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