I know about the backups bit, but I am not 100% sure if all of the space eaten by the local backups is indeed in the backups category due to the contradictory posts on the subject that I've seen on the forum. I suppose I could enable TM and the local backups and start doing some testing when I have some free time.
We all have our ways of doing things
Ok, so your way turns out to be better... I just tried to verify the size of the backups, and DiscInventoryX failed of course... they are stored in /.MobileBackups which the program doesn't see (or has no access to).
"du" correctly tells me that the directory has 1.9 GB of content, which seems to agree with the 1.87 GB that "About This Mac" reports. Although, to be precise, du says there are 2037 million bytes, while "About This Mac" only acknowledges the existence of 1870 million bytes. That's about a 10% difference, which might end up in "other."
A du on .Mobilebackups with depth 2 reveals the backups with time stamps:
Code:
$ sudo du -h -d2 .MobileBackups/
1.4G .MobileBackups//Computer/2011-12-27-182037
131M .MobileBackups//Computer/2011-12-28-221756
11M .MobileBackups//Computer/2011-12-30-012429
126M .MobileBackups//Computer/2011-12-31-025031
70M .MobileBackups//Computer/2012-01-01-033350
16M .MobileBackups//Computer/2012-01-02-035345
3.7M .MobileBackups//Computer/2012-01-02-165454
3.8M .MobileBackups//Computer/2012-01-02-175554
2.8M .MobileBackups//Computer/2012-01-02-185653
3.0M .MobileBackups//Computer/2012-01-02-195736
3.4M .MobileBackups//Computer/2012-01-02-220003
2.0M .MobileBackups//Computer/2012-01-02-220636
4.4M .MobileBackups//Computer/2012-01-02-221735
4.3M .MobileBackups//Computer/2012-01-02-230636
3.3M .MobileBackups//Computer/2012-01-02-235341
3.1M .MobileBackups//Computer/2012-01-03-000804
11M .MobileBackups//Computer/2012-01-03-001638
3.3M .MobileBackups//Computer/2012-01-03-005827
3.2M .MobileBackups//Computer/2012-01-03-011509
5.8M .MobileBackups//Computer/2012-01-03-012455
3.9M .MobileBackups//Computer/2012-01-03-021508
3.5M .MobileBackups//Computer/2012-01-03-031508
12M .MobileBackups//Computer/2012-01-03-100308
4.1M .MobileBackups//Computer/2012-01-03-102649
5.1M .MobileBackups//Computer/2012-01-03-113818
3.4M .MobileBackups//Computer/2012-01-03-122559
2.1M .MobileBackups//Computer/2012-01-03-132558
10M .MobileBackups//Computer/2012-01-03-142558
3.9M .MobileBackups//Computer/2012-01-03-152558
2.4M .MobileBackups//Computer/2012-01-03-162658
1.9G .MobileBackups//Computer
1.9G .MobileBackups/
The big file seems to be the weekly snapshot. My last external backup was before christmas. All local backups before that point are gone. The changes between the last external backup and december 27th are stored in the weekly snapshot. There is a 24 hour history with hourly snapshots, then 7 days with daily snapshots.
Once I connect the external backup (on thursday probably) my expectation is that the big weekly snapshot will be deleted. I'll let you know.
Bottom line: The unix way of doing things is most accurate