During rendering RIB files can consume signifigant amounts of disk space. Though such files are typicallly compressed, additional savings in disk space can be made by considering the inter-frame dependancies. Each RIB file is remarkably similar to its predicessor.
A semi-formal discussing of the approach can be read in this pdf.
To compress sequences of ribs we recomend the "-n" format of diff. In addition to being compact, it can be expanded with virtually no cpu or memory overhead, by a simple C program.
Here are some usefull programs and shell scripts which can perform the operations.