Crash Plan vs ???

I use crash plan to back up my main drive.
It stores the info gig for gig.

I was wondering if there was something that would somehow compress the data to a format that was more like 1g = 512mb or smaller.

I just dont see how i can hold the history of 4tbs on a backup hdds that are also 4tb. I mean, i probably dump 5gigs a year. how would i go back?

I am unsure about time machine but i was thinking that if it could store the history of a 1tb hdd thats half full for a year then maybe it is compressing the data somehow.

Is this true?

""" What you do with what you have, is more important than what you could do, with what you don't have."

> > > Knowledge + Action = Wisdom - J. Corbett 1992 """"