The SET COVERAGE command establishes the collection of test coverage data for all program locations specified by node specifications. The Collector places a breakpoint at each specified program location to measure test coverage. After you enter the GO command, the Collector determines whether each specified program location is reached during program execution. When a test coverage breakpoint is reached during program execution, the Collector records that program location in the performance data file. The Collector then removes the breakpoint so that the overhead of measuring coverage is not incurred in subsequent executions of the same program location. If you specify the /UNTIL:n qualifier, the Collector removes the breakpoint after the nth execution instead of the first execution. You must collect stack PC information if you want to use a /MAIN_ IMAGE, /CUMULATIVE or /STACK_DEPTH qualifier with the PLOT or TAB command in the Analyzer. If you enter the SET COVERAGE command before entering a SET DATAFILE command, the Collector establishes a default data file. The default data file has the same file name as your program's executable image file and a file type of PCA.