What’s this about Disk images?

Once again, we have some folks discussing how complex and difficult it is to install software on the Macintosh….

Namely:

But what I believe is missing here is a small feature that Apple implemented in the late 1990’s, maybe very early 2000’s.. Internet-Enabled Disk Images.

IE Disk Images, were created to help automate the Software Install process. I believe that most Disk Images were being created for several reasons.  Zip Files did not become popular for Macintosh software, since Stuffit’s .hqx format had been the king of the archives on the Mac for quite a while.

  1. Better Compression, so small download files. Remember this is when 26000 baud (dial up) was considered fast.
  2. Disk Images allow the author to place the software license in front of the user when the image was being mounted.
  3. If the file was damaged during the download, the user would know immediately. In other words, the author is guaranteed knowing that the user is not dealing with a damaged download. In the past there has been other software that would attempt to “fix” damaged zip archives, etc, with mixed results.

The Internet-Enabled Disk Image seems to answer the majority of the issues that other people are commenting about…

A typical download on the Macintosh follows these steps:

Disk Image  (Assuming that Safari is set to not automatically open safe files):

  1. Download the Software Package
  2. Open your Download directory
  3. Double Click on the Disk image
  4. Copy the application to the Applications folder (or where you want it). This is assuming that the software does not use an installer…
  5. Eject the disk image
  6. (optional) Throw the disk image away

Steps 2, and 3 are not necessary if Safari is set to allow the opening of safe files. In that case, when Safari finished downloading the Disk image would automatically be opened, and the disk image folder would normally be “waiting” already opened…  

Now the same workflow, but using a Internet Enabled Disk image…

  1. Download the Software Package
  2. Open your Download Directory
  3. Double Click on the disk image (& wait a few seconds)
  4. Copy the application to your Application folder

The Internet Enabled Disk Image, automatically copied the contents of the disk image to the directory you opened it in, and then ejected itself, and threw itself into the trash.

Here’s what Apple has to say about Internet Enabled Disk Images:

Internet-Enabling a Disk Image
Although all disk images can be transported through the Internet, users need to open them, retrieve their contents, and discard them. An Internet-enabled disk image automates this workflow. After a user downloads an Internet-enabled disk image from a network using a web browser, the image is automatically opened, its contents placed at the user’s download location, and discarded (in the Trash). This improves the manual install experience by performing a few tedious tasks for the user.

To Internet-enable a disk image, use the hdiutil(1) command-line tool, as shown
    hdiutil internet-enable -yes < .path_to_disk_image>

I’m not sure why more developers are not Internet-Enabling their disk images, I suspect that it is due to a lack of research… After all, Internet-Enabled disk images where created somewhere around the late 90’s… But the truth, I suspect, is that most authors are using a tool to create their DMG, and I suspect that those tools do not have an automated method to create an Internet-Enabled disk image…. So thus, instead of creating a script to automate the addition of the IE “flag”….. We get ordinary disk images….

I maybe completely wrong here, but….. It would interesting to get another view point on this….

Anyone have any comments?