When I copy files, I just copy. I don't bother checking to see if the data is the same. It's easy to check if the filesize is the same, or the date, or the name, but what about the data? Recently I decided to check through a backup drive to see if the data was identical on both backup and primary. I did a binary comparison with Beyond Compare, and it turns out it wasn't!

Though a few files had the same date, the same size; even worked the same, there were differences in the binary data.

I don't know what significance this has. Does it mean the drive is breaking down? Does it mean nothing at all? Fortunately I know which drive is primary and which one is the backup, so I can easily copy over the 'original' files to the backup drive once again, and maybe run another binary check to see if there's still any difference. I used to use various programs to speed up copies between drives, but they were problematic, so I switched back to the no-program alternative. IOW the built-in Windows 7 explorer. As far as I know it verifies files for inconsistency errors after each copy, so that makes it all the more mysterious why the files aren't exactly the same.

It should be noted that comparing thousands of relatively large files binarily takes a lot of time. The directory that needed checking would have taken an estimated 25 hours if I had let the scan run. I didn't, I just tested comparing a few files. Now that I know there are differences I will need to run a full scan. Wouldn't be a problem if I didn't use the computer, but I do. :) Anyway, realizations everyday. If anyone reading this knows anything about the questions posed, do answer. Also, a question, would a binary comparison or a comparison through checksum/hash be more efficient? Later.