View Full Version : DMG.files

12th January 2010, 09:23 AM
Have a few assorted flash drives configured to work with Truecrypt. I also have a 16GB Corsair Voyager with 15GB configured as a DMG file.
When copying files to the Lacie(s) and Sandisk(s) they copy in an instant. The same file (140mb) takes 5 minutes to copy to the Corsair.
Had a look around, no answer's readily available, anyone ?

12th January 2010, 12:08 PM
USB 2.0 isn't as fast as many think, and vastly depends on how many separate files are copying through it.

If the 140 MB is composed of lots of small files, it will take longer, and as mounting DMGs directly from USB 2.0 Externals may be faster, as it is only mounting one file, rather than copying anything.

12th January 2010, 12:39 PM
The thing is that out of five flash drives all (at different times)connected via the same cable and USB port only one takes for ever to copy the same file. And only the Corsair is configured with the 15GB DMG.file, the remainder have Truecrypt containers.
I ran diskutils over the Corsair, everything is OK. Specs for the Corsair are on par with Lacie and Sandisk.
Wonder if copying to a DMG file/container is the problem.

12th January 2010, 02:24 PM
Get yourself a Mini G2 with FireWire 400 or FireWire 800.
See here (http://forums.mactalk.com.au/18/34587-external-drives-dummies.html) beneath the Clearlight model.

Tiny thing. Self powered on FireWire and USB. Can hold a current maximum of 640GB.

12th January 2010, 03:07 PM
The Corsair isn't a flash stick is it? Those have quite slow write times for some reason, but the read times are full USB 2.0 Speeds.

12th January 2010, 04:11 PM
To actually answer the question; copying a file to a DMG is definitely going to be slower than otherwise, plus it can also depend on the settings used when creating the DMG.

As to whether a DMG is slower than a TrueCrypt container, I'm not sure. Swapping the functions of two of the flash drives temporarily would allow you to make sure.

12th January 2010, 07:42 PM
Not sure what you mean by settings, from the top of my head I can't recall doing anything other than choosing the size of the DMG. I have all my important stuff on 2 x 500GB external HDD and files I can't live without on the flash drives, 2x car keyrings 1 in my car and two in my dwelling all encrypted. 5 may be excessive but as we all know they fry easily. Anyway thanks to all for your input.