the early patriots suck due to an numerical error in its calculations:
" A report of the General Accounting office, GAO/IMTEC-92-26, entitled Patriot Missile Defense: Software Problem Led to System Failure at Dhahran, Saudi Arabia reported on the cause of the failure. The Patriot missile failures in Desert Storm were due to roundoff error because the system was designed to be on alert for only a few minutes at a time. Instead, they ran continuously for days. The clock, which was storing time in floating-point, began to have too many digits to the left of the decimal place and not enough after the decimal place to do accurate timings of incoming SCUD velocities."
now don't all of you just want to take Numerical Methods for Engineering??