Deployment :: Make Patch Maker Binary Differential Update?

any1 has any ideas on how to code a patch maker, (binary differential update) so when i run my patch maker, it output a program (*.exe) that will update files on another machine or local machine, assuming that old files to be updated to a new file having the same data in result;

and also the output patcher should be smaller in size (compressed)currently wad i could think of is a very very simple one but totally useless and not efficient and result large file size patch

1. where mine is read both file data
2. is both byte the same ?
3. [if not same ----> write down the marker value in outputfile1 and byte value in outputfile2]
3. [if same ----> do nothing]
4. read byte if available
5. (marker + 1)

the marker value is how many byte have been advanced so with resulting patcher will read those marker values to advance to the file address (which is the position number) and update accordingly to its byte value outputfile1 is marker values, outputfile2 is byte values corresponding to outputfile1 marker value to advance to the byte position