Is there any program, which can store all versions of files, as they appear on disk?

"For automatic unobstrusive versioning, you could use RSync coupled with the equivalent to a cron job in Windows.
You could also use SVN, but it would be more obstrusive, and it might be bad to store many binary files in it.

One caveat: This are not simple point and click tools.
You can modify them to suit your needs, almost any need, but other, commercial, applications might be better suited if your needs are solved by the application and don't want to be fiddling with scripts and what not."

"Actually, Genie Timeline automatically scans the machine and detects any changes in files to include them in backup.. it works in real time as it scans the system and adds any changed files to backup.. it bask up files that are open as well.

it keeps multiple versions of your files so that if you ever need to go back and recover an old file, you can choose to restore any version of that file..."

"I've had good luck with FileHamster. Basically, you set it up to watch a folder and it archives files each time they are updated or changed.

The basic version used to be free but it recently has changed to paid for all their versions."

pretty much any backup/sync software will do that for you. schedule incremental backups of your hard drive(s) and use filters and wildcards (e.g. *.doc will only copy newly created/modified word documents)