Abstract: Methods, and systems consistent with the present invention can detect out-of-range data conditions, such as when an overflow occurs or when the instruction attempts to operate on invalid data, during the execution of windowed code. Specifically, methods and systems consistent with the present invention maintain a list of instructions to be monitored and then execute the instructions with hexadecimal data. Such methods and systems can determine when a year 2000 problem exists with a particular instruction by comparing the list of instructions to be monitored with the instructions after the substituted data.

Abstract: System for suspending operation of a program after detecting that an instruction is executing with an operand assuming an out-of-range value such as a year value out of the range of the program. After suspending operation, the reason for the suspension is determined based on a set of rules and the proper result of the instruction is determined and inserted. If the reason for the suspension was a date value was out of range, the date value is put in a different format. Operation of the program may then resume.