For each program, we examined:
• IMS databases and segments used
• Data Language/I (DLI) calls
• Input, output and updated files (usually VSAM)
• Lines in the program
• DB2 tables used
• Read-only and update SQL statements
• Called programs and the number of calls to each program
• WS copybooks performing IMS functions and copybooks for IMS segments, indices, etc.
Additionally, for each online program, we examined the commarea and number of XCTL (transfer of control), LINK, LOAD, etc.
To improve the accuracy of the time estimate, we quickly “test converted” one program from each category and adjusted the estimated time for each category accordingly. This required 16 hours.
Reporting the Results of the Analysis
Using the complexity levels assigned in the last phase, we produced the conversion estimate shown in Figure 3.
Our automated analysis process for the IMS to DB2 conversion saved a tremendous amount of time—more than 90 percent—in man-hours alone. The analysis took one week (for two people). Yet if done manually, it would typically have taken two months for a team of four. The automated process quickly provided the locations and characteristics of active application elements that required conversion and, just as important, those that were obsolete and could be eliminated.
This process greatly accelerated the conversion project by providing the ability to quickly analyze enormous amounts of data and avoid time-consuming, error-prone manual analysis. The same process provided the basis for guiding the project through the coding, testing, acceptance, and production implementation phases.