What is a dmg file?

I am new to Mac. i recently purchased a MacBook pro and downloaded Firefox. there is now a file called firefox.dmg on my desktop. is this just the installation file or the actual program? i have double clicked on the file and another window opens. i then double click on it and the file opens. question: do I need to keep the dmg file or do i delete it after i download the file and install it? where is this program located? also, can anyone point me to a reference site/ book. sorry for the multiple questions. just needed to get the file naming straight. thanks in advance.

MacBook Pro 17", Mac OS X (10.4.10)

Posted on Jul 10, 2007 9:18 PM

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2 replies

Jul 10, 2007 9:24 PM in response to arjethva

The .dmg stands for 'disk image'

Think of it as a portable disk that gets mounted (inserted) when you double-click. Once it's mounted, you have access to its contents - in this case the Firefox application. Now it is possible to run the application from the disk image, but when you eject it, you will no longer have access to it - until you mount it again.

So, after mounting the disk image, copy the application icon to your /Applications folder. You can then drag the app icon from the /Applications folder to the Dock to create a shortcut and it will run off the copy on the hard disk. Eject the mounted disk image (⌘ E) and either delete the .dmg or save it for backup purposes.

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What is a dmg file?

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