Monitor - Version 1.0 Monitor is a library of 10 Fortran subroutines: Delay False, Delay True, Differential, Integral, Lag, Latch False, Latch True, Lead, Lead-Lag, Rate Limiter. The free demo compares Monitor's output to the algebraic answer for several cases. It opens up a DOS window for user input and the output is stored in mdout.txt. You have 2 full-version packages to choose from. The 1st contains Monitor.lib, the demo, a manual, and sells for $20. The 2nd adds the source code and sells for $35.