Yes, if you don't want to make modfolders in the ArmA 2 directory, you can do that.
I already explained this. Running on different hard drives spreads the load of the hard disk usage, and in some cases expanding the data transfer rate. This does not work on all systems but it should work on the majority. if you read the first post about this it says If you have 2 hard drives and are not running raid
under the title of Run on multiple hard drives
. You asked, if it would be possible to use this on a single hard drive, the answer in general is no, I thought that much would be obvious. However, yes as I stated you could use a different directory for addons and files for ArmA 2 if you so desired - the point in this is simply for organisation purposes.
This also works if you have a USB flash drive.
Ah Ok, I misread it thinking that you said, If you don't have raid and you don't have 2 hard drives.
Anyway, this guide is very useful, I just re-installed my OS and it works like a charm. If there was some way to give awards on this site, one will certainly go to you, good job! :thumb