.sit vs .dmg

Posted:
in Mac Software edited January 2014
I'm looking at the compression rates, and it seems like i should just archive in .dmg--it can compress almost as much as .sit, and it'll work on any OS X system.



is that the one drawback--that .dmgs fon't work on other platforms?
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Comments

  • Reply 1 of 37
    aquaticaquatic Posts: 5,602member
    I never understood the point of disc images. They add phantom drives to your drive list, they add an extra step, they just suck.
  • Reply 2 of 37
    jlljll Posts: 2,709member
    Quote:

    Originally posted by Xidius

    Actually.. A disk image does not compress at all.



    They certainly do - if you choose to make compressed images.
  • Reply 3 of 37
    jlljll Posts: 2,709member
    Quote:

    Originally posted by Aquatic

    I never understood the point of disc images. They add phantom drives to your drive list, they add an extra step, they just suck.



    Internet enabled disk images actually remove a couple of steps.



    Read this discussion:



    http://forums.macnn.com/showthread.p...hreadid=155030
  • Reply 4 of 37
    kim kap solkim kap sol Posts: 2,987member
    .dmg is hands down the best methode of distrubution on OS X right now.



    The advantages are too numerous for me to bother writing them.
  • Reply 5 of 37
    Quote:

    Originally posted by Xidius

    Actually.. A disk image does not compress at all.



    JLL already pointed it out, but I just wanted to rub it in a little more.



  • Reply 6 of 37
    defiantdefiant Posts: 4,876member
    ***CONFRIMED!!***



    In an strange move, Brad today showed the world that he also uses a theme. AI is beginning to show signs of paranoid people-...



  • Reply 7 of 37
    mrmistermrmister Posts: 1,095member
    BUSTED!
  • Reply 8 of 37
    <digression>



    Actually, guys, it may surprise you to know that I and "themexican" and Dave were the first guys to make real themes (over at the MacNN forums) back in the Mac OS X Public Beta days, years ago. We were the ones to kick off the theme "revolution", if you want to call it that. That's why I know so much about themes, how they work, the files they change, and why they can be so dangerous.



    Everything I do with themes today I do myself. I manipulate all the rsrc files and such myself by hand in Resorcerer, ThemePark, Iconographer, etc. I also don't use any of those crufty installers like MetamorphX or ThemeChanger or the like.



    </digression>



    And now back to your regularly scheduled discussion of compressed file types.
  • Reply 9 of 37
    dfilerdfiler Posts: 3,420member
    Quote:

    Originally posted by Brad

    ...

    I and "themexican" and Dave were the first guys to make real themes (over at the MacNN forums) back in the Mac OS X Public Beta days, years ago. We were the ones to kick off the theme "revolution", if you want to call it that. ...




    What a coincidence! I invented the wheel.



    Remember Aaron? It provided platinum appearance during the time between apple demo-ing the new look and the next Mac OS release. Kaleidoscope offered a full themeing system prior to the platinum look as well.



    But back to the 'official' topic...



    Disk images are an elegant solution from the developer's perspective but are quite unintuitive. Isn't it easy to forget what novice users have trouble with? It wasn't until I observed inexperienced users attempting to install from disk images, that I realized just how confusing the process can be. There are a number of steps that users frequently forget. These include: Forgetting to copy the app into the applications folder. Later the image is trashed and they are confused by why the program no longer exists. Or, they run the program, 'great it works!', and then immediately try to trash the disc image, which is in use. I've also seen users double click on the downloaded image and assume that the program was decompressed and ready for use... but wait its not in the applications folder or where they downloaded to? Heheh.



    I prefer disk-images to other distribution/compression format even with these shortcomings. Apple is aware that the process could be more streamlined. This was their motivation behind safari and web-enabled disk images. They eliminated one step from the download/installation process. Also, apple fixed it so that trashing an image and the mount works without producing an error from the image being in use. Next up... hopefully the subsequent installation process can be made easier for novices without resorting to wizards or limiting/changing expert user workflows.
  • Reply 10 of 37
    kim kap solkim kap sol Posts: 2,987member
    Quote:

    Originally posted by dfiler

    What a coincidence! I invented the wheel.



    Remember Aaron? It provided platinum appearance during the time between apple demo-ing the new look and the next Mac OS release. Kaleidoscope offered a full themeing system prior to the platinum look as well.



    But back to the 'official' topic...



    Disk images are an elegant solution from the developer's perspective but are quite unintuitive. Isn't it easy to forget what novice users have trouble with? It wasn't until I observed inexperienced users attempting to install from disk images, that I realized just how confusing the process can be. There are a number of steps that users frequently forget. These include: Forgetting to copy the app into the applications folder. Later the image is trashed and they are confused by why the program no longer exists. Or, they run the program, 'great it works!', and then immediately try to trash the disc image, which is in use. I've also seen users double click on the downloaded image and assume that the program was decompressed and ready for use... but wait its not in the applications folder or where they downloaded to? Heheh.



    I prefer disk-images to other distribution/compression format even with these shortcomings. Apple is aware that the process could be more streamlined. This was their motivation behind safari and web-enabled disk images. They eliminated one step from the download/installation process. Also, apple fixed it so that trashing an image and the mount works without producing an error from the image being in use. Next up... hopefully the subsequent installation process can be made easier for novices without resorting to wizards or limiting/changing expert user workflows.




    Yes....you *could* look at it that way. But disk images grants the user the control over where the app is installed. The user knows where it's been installed because he dragged it out of the disk image.



    I suppose it does confuse a lot of users. They're probably from the MS camp where installers decide where the app should be installed, end of story. Some people might say installers are great...you don't need to do anything...the computer decides for you.



    I'm all for computers doing the bulk of the work for people...but computers organizing your stuff for you? That's a no-no.



    Disk images are intuitive...users have just been brainwashed by MS is all. Macs have always worked this way since 1984. You inserted a disk and drag and dropped the application or documents from your disk to your HD (well...maybe not in '84 but later when HD were introduced).



    Things haven't changed in Mac land. MS has changed people's way of thinking though.



    A lot of developers are starting to add little comments in a window background picture: "Drag this app to the Applications folder" with big arrows pointing to the icon. If the user still can't figure it out, they might as well go back to Windows.
  • Reply 11 of 37
    dfilerdfiler Posts: 3,420member
    Quote:

    Originally posted by kim kap sol

    Disk images are intuitive...users have just been brainwashed by MS is all. Macs have always worked this way since 1984. You inserted a disk and drag and dropped the application or documents from your disk to your HD

    ...

    A lot of developers are starting to add little comments in a window background picture: "Drag this app to the Applications folder" with big arrows pointing to the icon. If the user still can't figure it out, they might as well go back to Windows.




    I think it is a mistake to view installation via disk images as intuitive. At the same time, please note that I do not advocate proliferation of installation wizards or even the most succinct installer applications. However, there is still much room for improvement in the tasks that disk images are currently used to accomplish.



    Why are disk images unintuitive to users who aren't computer experts? Hmmm. It can be difficult to explain this as one forum geek to another, but let me try.



    For most people, the concept of a virtual disk or disk image is not an easy concept. On the other hand, disks-on-the-desktop has proven to be very well understood and even anticipated by novice mac users. While many easy concepts seem like they should be intuitive to users, this one has actually been proven, in real world use, to be well understood by even novices. Stick in a disk and it appears on their desktop (computer).



    However, it doesn't follow that these users can understand the concept that some files , downloaded from the internet, will be compressed, virtual disks. It isn't intuitive that only some files will need to be made into a fake disk. The whole concept of a fake disk is indeed, quite counter-intuitive. First the application that they downloaded must be decompressed. Then it must be double clicked. Then the user must realize that this created a fake disk and that double clicking on the disk will show what they downloaded. Next, they must make the connection that while it is possible to double click on the application, what they really want to do is move the files to somewhere on their drive. Next they must realize that trashing the disk does not erase what they have downloaded, that trashing the disk does not erase anything at all. (usually)



    Notice, that there is a difference between a task being easy and a task being intuitive. Disk image based installation is 'easy'. However, without a pretty good understanding of computers, the file system, and disk images, installation via disk images is simply not 'intuitive' to most users.



    Microsoft took the easy way out and resorted to using wizards for almost all installations. Users need no a priori knowledge when using wizards, simply choose between a list of predefined options. Yet many of us here would agree that wizards are dangerous to our computing culture, allowing users to remain completely oblivious to how and where things are stored on their computers. Wizards and installation apps are also cumbersome to experienced users. They may tamper with things without us ever knowing. They may also limit our options. Finally, they make developers more likely to structure an app so that it is less self-contained, spread around the system in a haphazard manner.



    While images may currently be the best compression/distribution/installation option for OS X applications, they are far from intuitive. There is much room for improvement in the distribution and installation process. Even after these improvements are made, I'm sure we'll still have disk images for storing exact copies of physical disks.



    Disk images, as currently implemented, were never designed for making installation of their contents intuitive for novice users.
  • Reply 12 of 37
    kim kap solkim kap sol Posts: 2,987member
    Quote:

    Originally posted by dfiler



    Disk images, as currently implemented, were never designed for making installation of their contents intuitive for novice users.




    Well, until developers get their butts in gear and start using the Bundle concept and until the internet is fast enough so that people can simply download uncompressed Bundles, virtual disk images will remain just as confusing as a compression format such as .sit with the exception that the virtual disk image can be unmounted adding some degree of confusion to people that don't understand the concept...although it's a concept that's no more complicated than the concept of a compressed file...why aren't users confused when they double-click the compressed file and it doesn't launch (but rather uncompresses)?



    .dmg can be made to act exactly like a .sit file...Apple has shown this. The first time I downloaded Safari, the Safari app sat on my desktop as if it was uncompressed like a .sit file.



    .dmg just offers much more flexibility to both the dev and end-user.
  • Reply 13 of 37
    dfilerdfiler Posts: 3,420member
    Quote:

    Originally posted by kim kap sol

    ...why aren't users confused when they double-click the compressed file and it doesn't launch (but rather uncompresses)?



    .dmg can be made to act exactly like a .sit file...Apple has shown this. The first time I downloaded Safari, the Safari app sat on my desktop as if it was uncompressed like a .sit file.



    .dmg just offers much more flexibility to both the dev and end-user.




    I agree that disk images offer greater flexibility and they are my choice for distribution of applications. However, it is important to acknowledge flaws with the current implementation/usage.



    Disk images are more confusing than compressed files even if both of us, and most people on these fora, find both to be quite elementery. Here is why...



    When a user downloads something from the internet, they typically end up with a file on their desktop. If this file is just a compressed file, double clicking will usually uncompress the contents into the current directory, the desktop. The same is almost true with disk images. But there is a big however. The 'folder' (virtual disk) created by the double clicking the disk image is not actually stored for later use by the user.



    If a user trashes a disk image, they will loose everything generated by previously double clicking the downloaded file. This breaks a number of direct manipulation metaphors on which the Mac GUI is based. No longer can the object in question be delt with in the same manner as an object in the real world. Throwing the packaging to your office stapler in the trash does not also throw away the actual stapler.



    With real disks, the metaphor is also slightly broken in that the disk is ejected but not actually trashed and lost forever. The disk can always be reinserted if there is a problem. However, with disk images, inexperienced users can run into trouble. They can trash the compressed file (image) which they don't always distinguish from an image and inadvertently loose what they downloaded.



    This doesn't happen with compressed files, only disk images. Trashing a compressed file will not delete the expanded contents. This is intuitive. It isn't intuitive for trashing one file to actually delete an entirely different directory.



    Disk images are more complicated even though I consider them to be the best currently-available distribution format.
  • Reply 14 of 37
    kim kap solkim kap sol Posts: 2,987member
    Quote:

    Originally posted by dfiler

    I agree that disk images offer greater flexibility and they are my choice for distribution of applications. However, it is important to acknowledge flaws with the current implementation/usage.



    Disk images are more confusing than compressed files even if both of us, and most people on these fora, find both to be quite elementery. Here is why...



    When a user downloads something from the internet, they typically end up with a file on their desktop. If this file is just a compressed file, double clicking will usually uncompress the contents into the current directory, the desktop. The same is almost true with disk images. But there is a big however. The 'folder' (virtual disk) created by the double clicking the disk image is not actually stored for later use by the user.



    If a user trashes a disk image, they will loose everything generated by previously double clicking the downloaded file. This breaks a number of direct manipulation metaphors on which the Mac GUI is based. No longer can the object in question be delt with in the same manner as an object in the real world. Throwing the packaging to your office stapler in the trash does not also throw away the actual stapler.



    With real disks, the metaphor is also slightly broken in that the disk is ejected but not actually trashed and lost forever. The disk can always be reinserted if there is a problem. However, with disk images, inexperienced users can run into trouble. They can trash the compressed file (image) which they don't always distinguish from an image and inadvertently loose what they downloaded.



    This doesn't happen with compressed files, only disk images. Trashing a compressed file will not delete the expanded contents. This is intuitive. It isn't intuitive for trashing one file to actually delete an entirely different directory.



    Disk images are more complicated even though I consider them to be the best currently-available distribution format.




    Essentially you're just saying users are used to compressed files and become confused when confronted with a virtual disk image concept.



    Just like learning that double-clicking a compressed file decompresses the files in it, it's easy to learn that disk images act like physical storage media inserted into the computer.



    I realize that it's a concept that may confuse some people the first few times they try it but the learning curve just isn't as difficult as you make it sound.



    Compressed files were just as confusing back in the days when compression wasn't much used.



    I remember fiddling around BBS as a kid and trying to figure out why I couldn't open up Compact Pro and StuffIt files. I didn't know I had to get a program to do this. I was a little confused about why files were being put inside another file format (since I was young...not necessarly a computer novice but still unable to grasp the concept).



    If you sit a novice in front of a zip file, do you expect him to know how it works? No...but he'll eventually learn that these are compressed files that can be expanded.



    If you sit a novice in front of a dmg file, he won't know how to work it either. But he'll eventually learn that they act like physical disks.



    What you're saying is that someone is used to zip and sit formats and have difficulty to adapt to the dmg format...of course, that makes sense. But to say that sit and zip are more intuitive than dmg is nonsense.



    The advantages dmg has over zip and sit far outweigh what you consider unintuitive (which is rather a matter of accustomation, not intuitiveness).



    Have you ever downloaded a sit file onto an overcrowded desktop? It's hard to find the uncompressed file because the file is uncompressed and placed at some seemlingly random (where there's space) place. You end up having to look for it. Does this make sense? How is a computer novice supposed to figure out where the file went?



    At least with dmg files, you are forced to drag and drop it somewhere of your choice. You'll know exactly where it's been dropped. The only thing the user has to 'learn' is that a file has to be dragged out of the disk image...this is often reminded by a background image with little embedded comments in them inside the disk image.



    Conclusion: dmg is not unintuitive...like anything else, you have to learn the its difference to the other more common and format. It's not anymore difficult. Just a different concept.



    If you were to say dmg is difficult to understand because novice users are used to compression formats such as sit and zip, then I'd say "yes, you're right".



    Is having the close, minimize, zoom-to-fit widgets in the left portion of the titlebar unintuitive too? I mean, when a Windows user is sitting in front of my computer they often click the 'toggle toolbar' button in hopes that the window will close.
  • Reply 15 of 37
    kim kap solkim kap sol Posts: 2,987member
    Too bad installer packages already make use of a 'box' icon. I think .dmg files should look like a box. You open the box and it acts like a folder...and a little message inside the window should by default explain that you must drag and drop the file out of the box for it to be permanently installed but that keeping it in the box is ok as long as you keep the box and not trash it...like any real world object! WOW!



    Any app inside the Dock will automatically open an unmounted disk image and launch the app so as long as someone can get around the concept that disk images are like boxes and that you can trash the box if you actually remove things from the box or you can keep the box if you want to leave things in the box.



    It's not rocket science. Just the icon is deceiving I suppose which looks like nothing I've ever seen (even though it's supposed to represent a physical disk of some sort) and that you have the dmg file which mounts a virtual disk...so you've got 2 instances of what seems to be the exact same thing.
  • Reply 16 of 37
    dfilerdfiler Posts: 3,420member
    Quote:

    Originally posted by kim kap sol

    What you're saying is that someone is used to zip and sit formats and have difficulty to adapt to the dmg format...of course, that makes sense. But to say that sit and zip are more intuitive than dmg is nonsense.



    The advantages dmg has over zip and sit far outweigh what you consider unintuitive (which is rather a matter of accustomation, not intuitiveness).

    ...

    Conclusion: dmg is not unintuitive...like anything else, you have to learn the its difference to the other more common and format. It's not anymore difficult. Just a different concept.




    Well, at least you and I are in agreement about disk image advantages far outweighing their disadvantages. However, I'm sticking to the assertion that disk images are far less intuitive than compressed files.



    I'll try to state it in as few words as possible in case anyone besides us is actually skimming this thread.



    Scenario: A user downloads a file and double-clicks. (Sometimes the double-click is handled automatically.) The user wants to keep the uncompressed/mounted data created by this double click. With disk images, throwing away the original file also deletes the desired data. This isn't the case with compressed files.



    Disk images are counter-intuitive in that deleting one file actually deletes a completely different 'directory'.



    Since you don't believe that many users get tripped up by this... I'm betting you mostly hang out with college-students or employees at a computer related company. (No insult intended whether my guess is right or wrong)



    Home internet surfers and non-college educated office workers are completely different. It is very difficult for them to remember which file types can be trashed without worrying about this deleting things in another folder (disk).
  • Reply 17 of 37
    lucaluca Posts: 3,833member
    The disadvantage to compressed files or archives is that people may not delete the compressed file afterwards, leaving them with hundreds of MB of useless files all over the desktop.



    I don't know why installer packages are used more often. Double click, simple instructions, install, done. We're all geeks here, we find the concept of disk images simple. But I had no idea how disk images worked a year ago, and even now I'm not quite sure on some of the more complex aspects. I know how to use them but if you gave me one a year ago (before I really got into computers) I wouldn't know what to do with it.



    I don't think people have been "brainwashed" by the Windows method of the computer always choosing where the files are put. In fact, most installers for Windows let you choose, and most people end up just choosing the default anyway. Package installers don't let you choose the folder, I don't think.



    Basically what I'm saying is, for 90% of users, let the computer do the busywork so the user can get back to what they need to do.
  • Reply 18 of 37
    kcmackcmac Posts: 1,051member
    I can remember early on having trouble with disk images. Didn't really know what to do with them. This was in the first versions of OS X before the instructions "drag icon to applications folder" came with the open window as they commonly do now.



    What I still don't like is when you open a disk image and there are all kinds of files inside. This means you have to create a new folder to put them in and then drag the folder where you want it. That is when .sit is better because it comes as a folder that can be relocated. Eliminates a step.
  • Reply 19 of 37
    aquaticaquatic Posts: 5,602member
    Exactly. Disc images are stupid. A stuffed .pck is just plain better.
  • Reply 20 of 37
    lucaluca Posts: 3,833member
    Isn't it .pkg?
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