The program PROCSCAN was developed to monitor the profile of an executable image during execution. The purpose is to identify the routines where a program is spending most of its time. Thus PROCSCAN can be a very useful first step in program optimization. The output from PROCSCAN is a sorted histogram of subroutines versus time spent in each subroutine. The data represents a proportionate sampling of where the program is spending its time. Over a period of a few CPU minutes, a fairly accurate picture can be formed. If a program has been linked with the /NOTRACEBACK qualifier, or it calls routines contained within a shareable library, then PROCSCAN will not function.