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Free up drive space without losing content Storage Devices
Hard drive space is still a premium on laptops, and media files can eat a lot of that space. Here's a little trick to minimize the space taken up by applications that are not used frequently. It's a simple idea -- put the individual applications on individual compressed disk images using Disk Utility. Then create a folder for the disk image, and put an alias (pointing to the application on the image) in the folder with it. Store this folder in your Applications folder.

Some people may prefer to put all of their less frequently used applications on one compressed disk image. I prefer keeping just one application per disk image, since it takes less time to verify and mount the image. The compressed disk images take up far less space than the full application. In many cases, the disk image is at least 60% smaller than the full application.

When you need the application, just open the alias. The disk image is automatically mounted, and the application opens. It takes a little longer to launch the application, but it should be entirely acceptable for applications that are not used daily. Using this technique can free up a significant amount of drive space.

[robg adds: The only caveat with this method is that you may have issues during software updates -- the software updater will expect to find the applications in their standard location, in an uncompressed form. To be safe, you'd want to expand and copy all your compressed apps back to their normal locations prior to running a software update. But that could be problematic if you've used up all the space freed through the compression trick -- there won't be enough room on the drive for the expanded apps. I would recommend using this trick sparingly, and then only on the largest of rarely-used apps (GarageBand?), where you'll see the greatest space savings -- and remember to undo what you've done prior to running an upgrade. For third party apps, however, this seems like a very good solution (though you'd probably have to delete and recreate the image each time there was an update).]
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Free up drive space without losing content | 14 comments | Create New Account
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hmm
Authored by: mickeymoose on Jun 05, '06 08:08:27AM

Sounds slow. not only do you have to mount a dmg file every single time you want to open an application, it then runs slower (right?) from the dmg than it would from the hard disk. Also, any login items couldn't be stored in this way. Finally, this sounds like a RAM eater. but if you have a 10GB hard drive, it makes sense.

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narf?



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hmm
Authored by: dbs on Jun 05, '06 09:46:55AM

There's no reason this should be particularly slow. Sure it takes a while to access the disk image at first, but remember that you're only doing this for infrequently used applications, so that doesn't hurt much. After the disk image is loaded it may actually be faster since there's a higher likelihood that the relevant information has been cached in memory. The limiting speed factor here is the disk which means that a compressed image may actually get higher disk throughput than an uncompressed regular file. It would be interesting to compare the two.



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Movies?
Authored by: drowe on Jun 05, '06 08:33:58AM

I'm thinking this would be a good way to store movies you watch infrequently.



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Movies?
Authored by: blalor on Jun 05, '06 08:38:13AM

Movies are already fairly well compressed; you probably won't gain much with this trick for them.



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Free up drive space without losing content
Authored by: peragrin on Jun 05, '06 09:20:24AM

Applications don't compress a whole lot. Neither do images.

The solution delete your documents folder(backup first) and replace it with a compressed image file. The image will autoload whenever an alias to a file in there is opened or an application wants access to a file it knows is in there.

I do the same thing with an encrypted image. I moved the data files a particular application autoloads everytime it starts up to an encrypted image. When the application launches it asks for the encrypted image password and then finishes loading after the image is mounted.



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I thought once I was found but it was only a dream



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Free up drive space without losing content
Authored by: adrianm on Jun 05, '06 12:48:09PM

Applications can compress a lot, especially as most of the content textual resources or uncompressed executables.

Probably the best way to slimline apps is to remove all the languages you don't use, or even remove the architectures you don't have (ppc on intel and intel on ppc). These hints are almost certainly documented elsewhere on this site.



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Free up drive space without losing content
Authored by: dbs on Jun 05, '06 09:57:28AM

This should work very well for applications that consist of large numbers of small files, but poorly for continuous tone images or movies. An easy way to judge the potential savings is to just zip an application and see how much smaller it gets.

Since all files are made in 4kB chunks on HFS plus, the more files you have the more wasted space may be hanging off them. (I.e., a file that is 4.2kB of data will be 8kB on disk, resulting in 3.8kB of wasted space.) Compression will merge that space together. However, if the majority of the space is in non-compressible data (binary code, images, etc.) then the overall savings will be small.

For example: iCal has more than 3000 files inside the .app bundle. Uncompressed it is 27.3MB, compressed it is 8.2MB.

iPhoto has more than 13,000 files inside its bundle (!) and is 159MB uncompressed and 98MB compressed.

So the results will vary. (Of course simply removing all the localizations would probably have similar results.)

However I would be reluctant to do this for either iPhoto or iCal as they won't get updated with system updates. Doing this for the dozens of shareware applications I have would work very well, though!



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Free up drive space without losing content
Authored by: pub3abn on Jun 05, '06 12:28:21PM
However, if the majority of the space is in non-compressible data (binary code, images, etc.) then the overall savings will be small.

This sentence could be interpretted to imply that binary code and images are not compressible, but that is not true at all. PRE-COMPRESSED images formats, like JPEG or GIF, do not compress well. But others compress very nicely. Unfortunately some formats like TIFF may be either compressed or uncompressed depending on the file options used, so it is hard to tell without trying.

Binary application files compress quite well on average, which is precisely why even single-file applications are smaller when zipped.

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Free up drive space without losing content
Authored by: xSmurf on Jun 05, '06 10:15:02AM
I just got myself a MacBook Pro and even with this 100gb drive, it gets full quiet easily... Parallel, BootCamp (I didn't wanna say Windows here ;o). I found that by using TrimTheFat I could save a few hundred megs just by removing the PPC side of apps. Great little space saver app definitely worth the 0$ they are charging for ;)

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PM G4 DP 800 / 1.25gb / 120Gb+80Gb / CD/DVD±RW/RAM/DL
- The only APP Smurf

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Free up drive space without losing content
Authored by: itistoday on Jun 06, '06 11:52:23PM

Wow. If this isn't a hint already someone should make one out of it. Thanks!



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Free up drive space without losing content
Authored by: valx on Jun 05, '06 10:31:21AM
I forgot to add that I wouldn't do this with any of the default OS X apps for the exact reason that Rob specified. But it does work great on third party apps.

Since these apps are rarely used, the slight delay in launch is no big deal. There is no noticeable difference in RAM usage or the speed of the app itself--on my machine. I have about 70 apps stored this way and on average the compressed images are 50% smaller than the expanded app.

I have a 100GB HD. About 50GB is taken up with music and video. My entire home directory, minus music and video, takes up about 30GB. Using this technique has helped me have space left over for more media. :-)

As a side note, the app Disk Inventory X is a great freeware app that gives you a visual representation of what is taking up space on your HD.

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Free up drive space without losing content
Authored by: balthisar on Jun 05, '06 07:31:47PM

Well, I just replaced a PowerMac G4 with an iMac 17" -- yeah, I flip-flop -- the G4 replaced an iMac Graphite and it replaced a PowerMac 6400.

The iMac with its puny 150GB drive is at almost the same premium as a laptop. The only reasonable solution is an external drive for the videos. BUT... the latest version of Delocalizer saved me 1/2 a gig, which to me is substantial. It's a couple of years old with no future development, but it still did the trick. Also don't forget to go through all of your applications and destroy the readmes and legals and so on. You also have printer drivers for everything, modem drivers for everything, and background images you won't use, and user account images you won't use, and lots of documentation you probably don't even realize is there. Go ahead and trim down your /Library and /System/Library folders.



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--Jim (me)



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Free up drive space without losing content
Authored by: aGr[j5(6WU on Jun 05, '06 09:20:43PM

I think I'm the only person to post other than the OP (and robg) who has actually implemented this solution so far.
I created a disk image from a folder containing my least used apps: Audio Hijack; BootCD; CarbonCopyCloner; CD Spin Doctor 2; Colloquy; Cyberduck; Cypher; Epson Scan; File Juicer; Flickr Uploader; Fugu; Handbrake; MapMemo; Motion Pictures; Proteus; SiteSucker; and Typist.
Uncompressed these amounted to 66.7MB of disk space; using this hint they are reduced to a total of 24.7MB. I'd call this a satisfactory saving!
I also implemented this hint using the Britannica 2006 Concise Encyclopaedia, which weighs in at a hefty 435.6MB. This compressed down to only 399MB, and, unfortunately, didn't mount correctly when double-clicked. The decompression was also understandably slow, in contrast to the snappy mount of the former.
I'm certainly going to start using this technique on a regular basis as a means of saving disk space, though probably only with smaller apps, not the bohemoths!



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Free up drive space without losing content
Authored by: gjw on Jun 15, '06 01:02:53PM

"They" appreciate your kind comments. TTF has been mentioned here a couple of times in comments to other hints, but never seems to have made it to the big leagues on its own.



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