Question : Problem: How is it possible to compress 25GB to a 447KB file?

I only ask because it has been done. The file is a chess system, and it is only 447KB. When unzipped (which takes about 10-15 minutes to unzip), it becomes 25GB. The zipped file consists of twelve 2GB .ssm files and and one 500 MB installer. But how is this possible. What is a .ssm file and how can this be done?

http://solsticio_system.tripod.com/Inst_sol.zip

Answer : Problem: How is it possible to compress 25GB to a 447KB file?

The reason why it seems to compress very well is that most of the file is a repeated character (possibly 1's or 0's or whitespace, etc.)

Repeated characters compress very well.  For example,
111111111111111111111111111111
 could be compressed in a form that says
30*(1)

This is not a real example but in theory how run-length encoding should work.

psikic <http://cs.atu.edu/~bryan/>