I have a 1TB external hard drive of data that I have backed up from my main computer. To save space and give me the option of putting more data on this external HD, I'm considering compressing all of the data.
Windows 7 has the option of compressing a drive (right click on the drive -> Properties -> Compress drive to save space). Is it worth doing this type of compression vs. using something like 7zip to compress all of the contents of the disk? I don't plan on using the data any time soon, the drive is used solely as a back up for emergency situations.