Mounting an ISO image with readwrite permission


I am following these instructions for creating a cross-platform CD. I am coming across a problem in Mountain Lion where I cannot mount the image as read-write.

When I enter the following in Terminal:

hdiutil attach -readwrite ~/2013CD.iso

I get the following message:

hdiutil: attach failed - Function not implemented

Is there any way around this? I need to be able to mount the image as readwrite to make changes to it.

Best Answer

  • ISO 9660 (CD images) are not designed for writing. The entire filesystem is designed for efficient read only access.

    If you want to change part of an .iso you have three options:

    1. Copy all data. Change the copy. Generate a new iso file.
    2. If the iso is part of a multi-session CD, you can add new files and change the index. This will not change the old files, nor can you gain space by erasing files.
    3. Use an overlay filesystem. All writes go to the non-iso part, but show up as if they were in the iso. This is how many live CDs work.
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