The people at the Madrid, Spain-based ISV InCrew, provided some history on the development of backup compression. I’ve edited it a little bit to normalize the English, which is a heck of a lot better than my Spanish.

[O]ur Storage architecture manages to do that and more, but it’s not new and innovative, its called Delta Differential Binary Storage.

I’ve been working on this technology from 1992, and in 1996 working at IBM I started to develop a solution for software distribution based on this idea. We managed to reduce the Distribution package from 25 Mb to 1,5 Mb, ten years ago. It was a one person project and I had to use my free time when I was assigned to another project. To generate the delta files and to recover it, I used a reference dictionary in the OS files, in this way you have the reference dictionary already loaded in your computer. Xdelta has been around for a long time too.

I don’t know if it’s new or innovative for some people, but many others have been working for a long time on this technology. RSYNC is a clear example of this, is public and many system administrators use it.

On InBackup and InDrive we use this technology too, and not only to reduce storage space, we use to reduce backup window’s timeframe.

Are there any backup-compression mavens out there who’d care to comment further? If we can document some prior art here perhaps we can save some startup a lot of legal fees.

And One More Thing
Since this is Online Storage Week at – how did Increw know? – the following is appropriate.

Turns out InCrew is using this technology for a PC application that allows you to drag and drop files within Windows Explorer, automatically encrypts them, and FTP’s the encrypted files to a remote server. I’d like to hear more about it.