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How to Create an Encrypted Disk Image for Backup on OS XJanuary 30, 2008
This is an appendix to my larger Personal-Computer Backup article, just above.
(8-Feb-2008 update) Everything on this page works, but I didn't realize until just a few days ago that OS X won't reclaim unused space from a sparse image. You can use the hdiutil command (in a Terminal window) to recover some, but probably not all, the space, but it's extremely time consuming. It took over an hour for my 100GB image. I also tried just creating an encrypted non-sparse image, but Disk Utility took an excessive amount of time for that, and I killed it after more than an hour. So, I'm not sure that these huge disk images are practical. Regretfully, I'm now just writing directly to the drive, unencrypted. If I come up with a solution, or if someone writes to me with one, I'll post it here.
Most Mac backup utilities don't provide a way to encrypt the data, which is important if you're going to transport the drive or store it offsite. However, you can create an encrypted disk image on the external drive, and back up to that. Here's how:
Raw Conversion: Better Never Than Late April 24, 2008
Scanning in India by Way of California With ScanCafe February 15, 2008
How To Back Up Your Personal Computer January 30, 2008
Every Camera I've Ever Owned January 25, 2008
Sharpening JPEGs for the Web January 4, 2008
Lessons Learned From My Memory Problem December 20, 2007
Hunting Down a Mac Hardware Problem December 20, 2007
Trimming GPS Tracks With GPSTrackViewer November 13, 2007
The World's Shortest Camera Buying Guide September 22, 2007
Transporting and Storing Portable Backup Drives August 26, 2007
"The Luminous Landscape" Teaches Me to Print August 4, 2007
Creating a Google Photo Map (Revised) June 26, 2007
Sony GPS-CS1: Not Good Enough for Geotagging Photos June 24, 2007
Epson P-3000/P-5000 Multimedia Storage Viewer March 10, 2007
Trying Out Infrared January 20, 2007
Stupid Designs Hold Digital Back April 1, 2006
A small collection of my best photos (click the image). You can order prints, too.
The 2004 2nd Edition, a so-called "update" of the 1985 book, which turned out, not surprisingly, to be a re-write. Covers Solaris, Linux, FreeBSD, and Darwin (Mac OS X).
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