This is a great tool when used in conjunction with an external hard drive. It allows you to keep a very accessible copy of all your files on an external hard drive. No need for special backup software. No need to open archives or backups to find a file. Just navigate the 2nd drive to find your file.
NOTE: This tool does not version control or automatically create multiple copies of the file.
“This utility creates or maintains an exact duplicate of the original directory. ICE Mirror will compare the mirrored directory to the master directory and correct any disparities. ICE Mirror allows ultra fast mirroring because it performs incremental updates. In other words it only copies files that have changed. If only a few files have been updated, it performs very fast.
Also ICE Mirror allows making differential updates. The differential updates are very useful if you are use read-only media (CD-R, DVD-R, DVD+R, etc.). There are two steps in differential updates:
1. Comparison the master directory and the mirrored directory.
2. Copying all new files from the master directory to the secondary mirrored directory.In other words it only copies files that have changed in the mirrored directory to the secondary mirrored directory.”
http://www.ice-graphics.com/ICEMirror/IndexE.html