This assessment evaluates mainframe application developers on their proficiency in IBM Enterprise PL/I for z/OS environments. Candidates must demonstrate technical command over syntax, control structures, and complex data types including structures, arrays, and pointers. The examination requires deep comprehension of compile-time processing, preprocessor directives, and storage class attributes within the z/OS execution environment. Furthermore, participants must exhibit expertise in data manipulation through I/O statements, error handling via ON-units, and the integration of PL/I procedures with CICS or DB2 interfaces. Proficiency in utilizing the Language Environment runtime services and debugging techniques remains essential for resolving concurrency and memory management challenges within legacy systems.