Create a bootable backup - just OS + Apps

There's more involved than just finding out what files are needed. Since modern Intel Macs use EFI, you'll have to copy whatever is required to make the external hard drive boot. I suppose you could always use third party software such as rEFIt to boot the drive....

http://refit.sourceforge.net/doc/c1s1_install.html

How full is the 500 Gb drive? If what's on the drive will fit on the 160 Gb drive, you can always use a program like SuperDuper or Carbon Copy Cloner to create a bootable backup on the external drive. That's what I would do instead of trying to be selective.

Regards.

 

i believe with carbon copy cloner you can pick and choose what you want on your backup which will be bootable.

 

It would seem to me to be unnecessary to actually sort this out unless you have a lot of added apps on your original disk that you want to clone over. The reason I say that it would appear to be much more efficient to just do a fresh install of OSX on the 160Gb drive (and then install the updates) which would leave you with an up to date and essentially virgin install.

If you try to pick and choose which files are necessary to create a boot disk that will be very difficult, as there are many, many "hidden" files (look in the left hand column of Carbon Copy Cloner for example to see the huge number of system files that you are not seeing when you look at the directory in the Finder). In addition, if you have a bunch of added apps then you will then be forced to copy the "Users" directory as well all other the others to make sure that preference files, Application Support files, some license files etc. are still usable from the backup.

As was asked above, how much space is actually used on your 500Gb drive?

 

You must have at least one user for a proper boot disk. Best thing to do is to run your installer DVD on the external drive (make sure it's initialized as GUID), then after it's done select only the Applications from Migration Assistant. You'll still need to input a user, though.