Keith Bierman's Weblog

Tuesday August 28, 2007

When good files go bad...

My current (and past to be candid) laptop of choice is a  Mac.  Laptops being easily stolen, an encryption technology like Apple's FileVault really is a must. But what happens when  Something Bad(tm)  happens during shutdown? Well, the  image can become corrupt and then opening it is... well impossible. 

Or so everyone told me. Google helped a bit., if I had kept backups of the * sparse image itself,  I might have been able to use this technique.

Not being one to give up easily, I copied the sparse image to  another machine and started experimenting. having had good results from DataRescue in the past, I tried it. But as their  support organization confirmed, they do  can do nothignng for sparse images.

Diskwarrior could, but not so much with the version I had. So time to upgrade. Much to my annoyance, in the laptop itself the application bailed with a numeric error message. However,  working on the desktop  copy it ran flawlessly and restored the sparse image. It was then a simple matter to delete  the version on the laptop and copy it over.

Several lessons:

1. Always make sure there is a second account on the laptop (good hygene suggests  making it be the adminstrative account. But at least having a second account ensures a way forward ;>). 
2. Backups of course; but there's almost always some window of  vulenerability where the backup isn't current. So keep current on your restoration/hacking options ;> Alsoft only offered the upgrade  via CD, so by not having updated aggressively I cost myself a week of data outage.
   
3. Things which aren't really secret, put them in the /Users/Shared area. That way they don't  take up space in the  sparse image, and are there post data  disaster.

I still enjoy the strange looks I get running Solaris in full screen mode in coffee shops (via VMware's Fusion). Of course that requires an Intel based Mac.
 

Thursday August 09, 2007

Commuting between Linux and Solaris?

Often I find myself switching back and forth between systems, for a variety of reasons. While one certainly could use blastwave (or equivalent) to equip the systems identically, there's a couple of things which work just fine with some simple "mapping".

For example, if I've assigned myself the "Primary Administrator" role in my Solaris installation, there's no need for sudo. But it gets tiresome to retrain my fingers sometimes, so

alias sudo="pfexec"

does the trick. Similarly for prstat (alias to top).