Why does dmg always open in icon view?

Eric, the short answer is NO. First, the dmg is NOT on my Desktop, so I can't "select" it. hdiutil accesses it from a bash-script, and opens it, causing a disk-image to appear on my Desktop. Second, when there is a dmg on my Desktop, and I "select" it, command-J gives me the Desktop as the panel, with no choices for setting how it opens.

When I created the dmg from a folder, the folder was set to "Open in column-view mode", but when I open the dmg, the resulting disk-images has icon-view. I have to manually change that to column-view from the View menu.

Eric, I don't believe it's possible to get column-view from a disk-image. When you mount an external drive, one of more disk-images appear on your Desktop. Double-click any of them and you get a window with an icon-view. The same happens with the disk-image resulting from double-clicking a 'dmg'. That disk-image ALWAYS opens in icon-view, regardless of the View-settings associated with whatever was the source for the 'dmg'.

Well, I was wrong. The only reason I continued to get column-view from the Volume was because I didn't Eject it. I was able to double-click the 'dmg', and the Volume remained unchanged, but once it was ejected, double-clicking the 'dmg' brought back the icon-view.

Something else bothered me... There are two kinds of 'Get Info'. One is in Dick Utility, and for the 'dmg', it said, "writable: NO", while 'cmd-I' said the owner had read-write authority. Similarly, for the Volume, Disk Utility said "Owner enabled: NO", but cmd-I said the owner has read-write authority.

No matter what I did in Disk Utility, I couldn't get Images -> Convert to convert the 'dmg' to read-only. or read-write. The result (which replaced the 'dmg') ended up exactly the same with "writable: NO"for the 'dmg' and owner read-write for the Volume (when reopened) with icon-view again. Maybe my problem is unsolvable in Yosemite.

OK, I found what works for me. I want column-view, so I did these things:

1. Added my Downloads folder to a Finder-window in the Favorites column.

2. Placed my 'dmg' files in my Downloads folder.

3. Open a Finder-window (cmd-N) and click Downloads in Favorites.

4. double-click the 'dmg' I want to open.

5.. Close the icon-window that appears when the Volume opens.

6. In the Finder-window, I slide down to 'Devices', and there's my

'Volume' listed. I click that, and see a column-view of that Volume.

I can now deal with that column-view directly from the Finder-window.

One last thing ... there is a step 7.

7. Click on the boot-volume under Devices, which shows all Volumes in column-view.

You can work from there, or back under Devices where they'll also open in column-view.

If you don't do step 7, the volumes under Devices may open in list-view.

Unfortunately, your link to DSStoreFormat contains this statement:

On Leopard (10.5), the view-type information seems to be ignored.

That may be true for all further versions of Mac OSX.

I need help with: "first create a read-write dmg as usual." That's not 'usual' to me. How is that done? What options do I give to "hdiutil create ..." to make it read-write?

Simplification: I can open my 'dmg' wherever it my be. It doesn't have to be in Downloads.

I then follow steps 5 & 6 in a Finder-window. That's it.

I've created a web-page that explains what I've learned from this discussion.

https://sites.google.com/site/dickguertin/home/viewing-devices

I think I found the 'secret sauce'. The dmg can't be on the Desktop. It has to be in a user-folder like Downloads with the required View, scuch as column-view. I'm going to experiment further, and report back with the steps I took.