FILES THAT SHOULD BE DISTRIBUTED WITH THE IMPSHELL IMPSHELL.PRO - Source code for the entire system. IMPSHELL.EXE - Compiled code for the shell, ready to run. IMPSHELL.HLP - A tutorial and help file that can be accessed from the main menu of the shell. IMPSHELL.RUL - This is an example expert system. It happens to be an investment advisor. The shell uses the file extension .RUL for any application systems that may be created. README.TXT - Short information about the IMP Shell and how to start it up.