The security issue is a non-issue for software developers. Apple will fix it, and the worry over it (which I think is confined to Mac exports anyway) will pass. I don’t think most people know about it, and legitimate developers won’t need to worry about it unless dmg exploits become rampant.

undmg seems pointless to me. A tbz or zip would be smaller and achieve the same end. Same goes for internet-enabled disk images.

The nice thing about internet-enabled disk images is that Safari will attach the disk image, copy the files from it, and detach and Trash the disk image for you. But it does the same thing for zips, and zips are smaller than even UDBZ dmgs. So you should just use a zip at that rate.

I like the conventional disk image. I like how it isolates the app: If an app cannot run on an unwritable disk image (because it requires write access to itself or its parent directory), I consider it buggy and unworthy of my custom.

Yes, I know that any app I run can write to my home directory. That’s not the point: I see an app demanding to be on the startup disk (probably so that it has write access to itself or its parent directory) as a critical design failures, probably the first of several. Good OS X citizens can run just fine from a disk image, which is why that’s my first test of the app.

It’s not horrible to use dmg files, but they suffer from being an opaque format. Windows and Linux (or even OS 9) users who find themselves with a dmg are left with no idea what’s inside. At least with a zip file they can read the Read Me and see whether it might be worth trying out my app on a Mac. Sometimes I find myself downloading a program just to check out some of the files in the bundle–images, scripts, etc–and it’s nice to be able to do that even if I’m stuck on a Windows box at a library. And if you’ve ever wanted to extract a dmg at the command line, you might have noticed how annoying it can be–but see undmg for an attempt to make it easier.

Now with the recent security issue, I’ve noticed myself being more careful around dmg files from people I don’t completely trust, so I’m becoming even more hesitant to use them to distribute my stuff. As far as I can tell, a “regular zip” (not the Finder’s weird kind) should be able to hold most modern OS X apps, since resource forks are rare nowadays–and there doesn’t seem to be any real downside to that method. I guess I’d only prefer dmgs for apps with resource forks that are compatible with Jaguar.

Somewhat off-topic, why do so many people not “internet-enable” their dmg files before distributing them? I’ve always found the open dmg => wait for it to attach => drag app to destination => eject dmg sequence to be tiring, and internet-enabled dmgs circumvent all that bother. Is there any disadvantage to them?

I applaud the post regarding compression and archiving and how to distribute software. I hope many people read and heed. This is probably the best thread on this subject matter. Thank you for writing it up. Here’s hoping kernelthread.org and maybe a few other popular information sources will solicit you to republish it.

Thanks,

Scott