The answer to the booting problem is exactly right in
catroom's post just above.
The "r42" designation of Disk Warrior refers to the revision of the boot software on the disk. Each revision adds support for booting newer and newer Macs- and as of r42, the Macs introduced in early 2008 (including your 2.4Ghz MacBook) were not bootable from the disk. As was stated above, the current shipping version is now a DVD which carries the r810 designation- and that is the first release that will boot the early 2008 Macs. Sadly enough I fall into the same boat as my r42 disk will not boot my early 2008 Mac Pro either but I use the same solution by booting from one of my external clone backups and running the latest DW version (version 4.1.1- which is required for OSX 10.5.5) from it which works fine.
OK, so that is one thing- but one more thing that may prove more troubling to you is in regards to what you believe, as I did at one point, that DW does in regards to Defragmentation.
Simply put, running a DW session and then checking again in the graph mode will show 0% fragmentation and that is true-- but it is
not file defragmentation in reality. It is only
directory defragmentaton- that is, when complete all the directory entries on the disk will be in order but the actual files stored on the disk will still be scattered around the disk (fragmented) just as they were before you ran the DW session.
It is a very misleading impression that DW leaves (and don't get me wrong- I love having DW around and it has saved me on more than one occasion!) concerning fragmentation.
True defragmentation (while many of us would contend is virtually never necessary in late model versions of OSX- see
Apple's Document on Disk Optimization) optimizes not just the directory entries for a file as DW does but also the actual physical storage locations of files so that they are continuous. Programs such as iDefrag from Corolis Systems and the latest Drive Genius 2 by ProSoft Engineering both do full true disk defragmentation. Since I among others would submit that it is generally unneeded in OSX (most folks who support it have long backgrounds in other operating systems in which it is almost essential to do it), and some serious "data safety" considerations in doing the extended true defragmentation, you really need to make sure you want to take the risk in light of what it might do for your benefit. At any rate,
please do not start a real defragmentation session without a current and complete backup of your drive!
All it takes is one power glitch (among other things) during a defrag session to render your drive unusable until is reformatted and the data restored. Hey to be positive, chances are it will run through the huge amounts of data reading and writing just fine--
but....
Anyway, in response to your question about using it from the external drive, that can indeed be done, but it needs to be bootable so OSX (and Alsoft recommends that it be the same version of OSX as the drive you want to run DW on) needs to be installed on it. You cannot boot an external drive that only has the Time Machine backup on it unfortunately. If you need more info on that, just ask and somebody will answer soon I am sure! Probably a lot easier and more time efficient to just order the update from Alsoft to the r810 DVD and boot your Mac directly from it!
If you purchased DW very recently, I imagine they have some kind of "shipping charges only" type of upgrade process to minimize cost.
One other alternative to running it from an external would require that you have another Mac at hand. If you do have another that can support Target Disk Mode via a FireWire or Ethernet port you can install DW on the other Mac and then work on your disk which will appear on that Mac's desktop in TDM. Notes about using TDM can be read in the
Apple Target Disk Mode document. Note that although it doesn't mention it specifically in that document, Target Disk Mode in Leopard does support doing the same thing that it describes with a network (ethernet) cable instead of FireWire.
Oh BTW- you can also totally defragment a disk by backing it up to an external, erasing the internal disk and then restoring the data from the backup. After doing that all the files and directory entries will be in correct order-- until the next time you use the computer at which point the fragmentation process starts again!
