Difference between .dmg and .app

[Maneesh Godbole]

Someone was mentioning about turning a jar into an app in another thread and that caused a bit of a confusion for me.

I noticed that when I download some "installable" it is named .dmg and when I execute the application it, it is an .app file. Would I be correct in thinking this similar to .msi and .exe on windoze?

[Ulf Dittmer]

.app is like .exe, but .dmg is a disk image, not an installer. If you double-click a disk image it will be mounted on the desktop like any other readable device. There may be an option to have an application (possibly an installer) run automatically upon mounting a disk image, but that's not the norm.

[Maneesh Godbole]

Oh ok. Got it now.
Thanks.

[Hussein Baghdadi]

Why there is DMG in the first place? what is the purpose of treating a software as a device?

[Bear Bibeault]

Think of a zip file that acts like a mountable volume.