To run a program, ZShell simply runs the program as a subroutine. The processor takes the opcodes and does the according actions. The time it takes a ti-basic program to run the first time is its tokenizing time. Make a program, go see its size in [mem] [delete], now run it for the first time. Now go look at the size. ZShell looks for strings with a special signature. I think its 0 FDh at the start --Steve