Compression Question

[BLG]

I'm trying to make some space on my old HDD without getting rid of anything so I'm compressing a lot with WinRar. My question is if I have a folder that has about 10gigs in it, and in that are 5 subfolders each with lets say 2 gigs.
If I were to compress each subfolder then compress the main folder would I save more space then if I were to just compress the whole folder.

**This seems like an obvious answer/stupid question, I just would like to make sure, because I'm not exactly sure how compressions work so . . .

 

[SmokeRngs]

The only thing that would do is take up more of your time. You will not get better compression by compressing something that is already compressed with the same compression program. It's not likely you could compress it anymore using two compression programs either.

Just compress the whole directory along with the subdirectories.

 

[bashPenguin]

The only thing that would do is take up more of your time. You will not get better compression by compressing something that is already compressed with the same compression program. It's not likely you could compress it anymore using two compression programs either.

Just compress the whole directory along with the subdirectories.

Agreed. No point in recursively compressing everything, then compressing all the compressed files together. Compression algorithms generally exploit redundancies or data patterns in the data being compressed, so post-compression, the redundancies or patterns have already been re-encoded to create the compressed data. In fact, in some instances compressing compressed data could actually grow the data size (or could lower it, but it will probably not be a big gain).