What does "mount the .DMG file" mean?

Question

What does "mount the .DMG file" mean?

Well, I was wondering whether installing things on a Mac was any different from doing it on Windows. What I ussually do is either copy the installer onto the HDD and run the program or just plain run it from the disk. However, whenever I look up the subject it says "Mount the .DMG file" and I've been wondering what it means. =(

Remember, this is my first time buying a Mac... Soo... Yeah. <_<''

Prospective Mac Pro buyer, Mac OS X (10.5.4)

Posted on Aug 6, 2008 8:41 PM

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Answer 1

Kappy

Level 10

362,007 points

Aug 6, 2008 10:39 PM in response to Dragonic Darkness

No, .exe files are either executable programs or self-extracting archives. Not at all a disc image file. A .dmg file is not a program nor an executable file, it's simply a disc image that contains the executable program or its installer. The common archives used for OS X are .sit (Stuffit archives) and .zip (Zip archives.) There are of course a bunch of others but these are the most commonly used. Be sure you download The Unarchiver when you get your Mac to handle most archives - VersionTracker or MacUpdate.

On the Mac you will generally not see an extension of most files. OS X usually is set to automatically hide extensions although that can be changed system-wide or for any individual file. Executable programs in OS X will have a .app extension as opposed to the .exe or .bin extension normally used by Windows.

For more help with switching take a read of Apple - Support - Switch 101. OS X also has a lot of built-in help that can be accessed via the Help menu of any application.

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Answer 2

Kappy

Level 10

362,007 points

Aug 6, 2008 10:24 PM in response to Dragonic Darkness

Just double-click on the .dmg file and it should mount automatically. If it does not (which would be unusual) then select the file and press COMMAND-I to open the Get Info window. In the section labeled "Open With" select DiskImageMounter from the drop down menu then click on the Change All button. If DiskImageMounter is not an available selection then select Other. A file dialog will open in which you want to navigate to /System/Library/CoreServices/ where you should find it.

Note that a .dmg file is not an installer. It is simply a disc image not unlike a .iso file in Windows.

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Answer 3

Aug 6, 2008 10:27 PM in response to Kappy

Wait, weren't .DMG files what .EXE files are for windows? =(
Gah, now I'm confused. So, a DMG is an IMAGE, not a program or executeable file? (Note, I do not have my Mac yet. I'm just trying to prepare, so forgive me if I sound n00bish. =P)

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Answer 4

Aug 7, 2008 8:05 PM in response to Kappy

Well, I looked up what Disk image meant, and it says it represents the entire contents of a disk. Does that mean that by opening a DMG, I'll be sent to OTHER contents?
I'm sorry if I seem stupid, but I'm just having a bit of trouble wrapping my mind around this...

Also, I downloaded the Unarchiver (It IS freeware, right?), and it's in a zip file. I'm using Windows Vista right now, and upon entering the file through double clicking I found alot of files that had 0 kilobytes, yet the whole folder is 2,686 KBs. Now, does it just read this way because I'm using windows and it doesn't read how big .app files and such are, or is it because I got a dud folder? I noticed that the folder with Time Machine Scheduler 2.2 that I got has alot of 0 KB files too. So, I'm guessing it's just because of windows. Am I right?

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Answer 5

Kappy

Level 10

362,007 points

Aug 7, 2008 9:24 PM in response to Dragonic Darkness

First, don't download Mac files to Windows. The filesystems are incompatible.

As said a .dmg file is simply a disc image. It can contain the contents of a hard drive, a folder, or anything you wish to put in it. From Windows you must know what a .iso image is, so that's what it is except in Unix it's a .dmg file.

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Answer 6

Aug 7, 2008 11:07 PM in response to Kappy

I know they're not "compatible", but it was my plan to not fuddle up my new Mac with things like downloads, downloaders and torrent clients. =/
My PC is old and already messed up, so I was thinking of taking advantage of that and just downloading everything I want from there and transfering it to my Mac afterwards through a storage device. Why? Do PCs mess up the files or something?

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Answer 7

Kappy

Level 10

362,007 points

Aug 8, 2008 12:33 AM in response to Dragonic Darkness

There are substantial differences in the filesystems such that portions of files normally a part of a Mac program are lost on a PC. Archives are usually transferable without a problem, but don't open the archive and transfer its content. Just copy the .zip or .sit or .dmg without doing anything with it.

Note, that PCs cannot write to Mac disks. You will have to transfer the files to a FAT32 formatted device such as a USB flash drive.

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Answer 8

Aug 8, 2008 2:11 PM in response to Kappy

Well, I really didn't DO anything to them. All I did was double click the .zip files to see what was in them. I didn't really modify anything in them or unzip the files.

Do you think I should re-download the files, or do you think they'll be fine?

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Answer 9

Aug 7, 2008 2:07 PM in response to Kappy

So, basicly, it's a more refined, compressed form executeable file?

Sorry for relating it to windows, but I've been using PCs for pretty much my whole life. =/

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Answer 10

Kappy

Level 10

362,007 points

Aug 7, 2008 3:36 PM in response to Dragonic Darkness

No, .dmg files are not executables. Nor are they compressed archives. They are simply disc images like a Windows .iso file.

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Answer 11

Kappy

Level 10

362,007 points

Aug 8, 2008 2:18 PM in response to Dragonic Darkness

As long as all you transfer are the .zip archives it should be OK.

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