disk images - advantages/disadvantages?

Discussion in 'Mac OS X 10.3 (Panther) Discussion' started by shecky, Dec 23, 2004.

  1. shecky Guest


    May 24, 2003
    Obviously you're not a golfer.
    i have a 60GB HD on my 1Ghz TiBook running 10.3.5 which is starting to get more filled up than i am happy with - however since i occasionally need to reference all the work i have on the machine (i am a design student) i really am not comfortable actually removing anything major to a backup DVD, so i was planning on making compressed disk images using Disk Utility of all the past semester's work by semester so that way i have it on the machine, but it looks to take up something like half the space. Before i do this i had a few questions that i'd like people's opinions on:

    1- is there any disadvantage to a compressed disk image over a folder. is the likelihood for file corruption, etc.. the same/better/worse with a disk image as opposed to a regular folder? I understand a disk image has to mount so it may take a little more time to access the files but beyond that is there something i should be worrying about?

    2- is Disk Utility the best way to make compressed disk images from folders? anything else i should use? I do have Toast 5.x and as i recall ya can do it from there but is there any reason why i should?

    3- will making compressed disk images NOT allow me to see any data? will it kill any files? etc.. (i assume not but its worth asking)

    4- is there something better than a compressed disk image i should be looking at instead? these are going to be read-only type archives, just on there on case i need to show something or whatnot - the files in the disk image will in all likelihood not be altered.

    thanks in advance!
  2. madog macrumors 65816


    Nov 25, 2004
    Korova Milkbar
    I see no reason to create a disk image of a regularly used directory. The only advantage I would see is that the files would be read only, if that is your concern. About corruption, I don't see any advantage over a disk image or a regular folder. If anything, I would consider a disk image more secure.

    Disk images made by Disk Utility [.dmg, .cdr] are only useable by Apple computers with OS X as far as I know. Toast is a multi-platform application and thus allows you to share .toast images with Windows users [if they have the appropriate app to do so]. It would come down to personal preference if non of those reasons are a factor for you.

    Maybe if an error occurs during the compression of a folder would it prevent certain data from appearring, but I don't think you'll have much of a problem with that. The only time you can "kill" a disk image [either .dmg or .toast] is if it is meant to be a bootable copy. For example, if you make a disk image of DiskWarrior or your OS X install disk, mount the image at some point, then burn a copy from that image, the resulting CD will most likely not be bootable. I'm not sure, but for some reason the Mac OS will add files[?] to a mounted disk image causing it to not work properly any time after. As far as I know, the only way to prevent this is to Get Info... on the image and lock it before mounting, preventing the changing or addition of any data on the mounted image. This is not a problem, however, when working with any regular or non-bootable images.
    Well, if space is an issue, you can always just create an archive of the folder through OS X [.zip, which from my experience works perfectly fine with any Win XP box] or with third party compression such as Stuffit or MacRAR; though a simple right-click and create archive method is by far the easiest. This is nice because you have the option to edit any enclosed files after decompression and can choose to a create a new archive with the saved data if needed. The down side is that you always have to delete the decompressed folder after use or you are just wasting space.
    If you intend these files to always be read only, then a compressed disk image would do just fine.

    Oh, and the reason I mentioned creating a .zip/.rar/.sitx archive is because I didn't really read your posting all the way through and because I don't know which method results in more free disk space. That's something you should check out.

    I haven't really used 'compressed' disk images all that much so I could be missing something, but I hope this helps out some ;)
  3. MisterMe macrumors G4


    Jul 17, 2002
    If you mount a compressed disk image, it will behave just like an uncompressed disk image. Usually compressed images are read only. If that is the case, then you will not be able to edit files on the image. Either way, you will be able to see all visible files on the mounted image. Contrary to other posts in this thread, you can create bootable CDs from images files that are properly configured. The properly configured image may be a copy of another CD or an original image created using using a utility such as BootCD. Disk Utility is perfectly capable of copying a bootable CD to a disk image and then burning a new bootable CD.

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