Invocation matrix 202 includes a row (row 7) labeled P1 corresponding to process 200. Invocation matrix 202 also includes rows (rows 8 and 9) for each of the other two illustrative processes yet to be described. (The reason for including rows for the other processes will become apparent as the procedure is described.) Row 7, column 1 of invocation matrix 202 has a value of one to denote the initial call to MS1. Row 1, column 2 and row 1, column 3 are both one, which denote, respectively, MS1′s invocation of MS2 and MS1's invocation of MS3. Row 2, column 5 of invocation matrix 202 is one to denote MS2′s invocation of MS5. Row 3, column 1 is one to denote MS3's invocation of to MS1. Row 5, column 6 is one to denote MS5's invocation of MS6. MS6 concludes execution of process 200, which is indicated by one at row 6, column 7 of invocation matrix 202. All other row-column elements of invocation matrix 202 are zero.