Make Update and Update are a set of applications to update an older version of 
a file (or files) to a newer version.  They work by finding just the differences 
between the two versions and applying those differences to the older version.

This is especially useful when you need to maintain common versions of large 
files at remote locations and the differences between the two versions is small.  
Another use is to "patch" files or applications -- that is, to provide updates 
of files (e.g., applications) to current users without making the contents of 
the entire files available others.