Error Message

Enhanced Definition

In the z/OS environment, an **error message** is a textual notification generated by the operating system, a utility, or an application program to indicate that an unexpected condition, problem, or failure has occurred. Its primary purpose is to inform users, operators, or other programs about the nature of the issue and often provides clues for diagnosis and resolution. In the mainframe environment, an **error message** is a textual notification generated by the operating system (z/OS), a utility, an application program, or middleware (like CICS, DB2, IMS) to indicate an abnormal condition, a failure, or an issue that requires attention. These messages provide crucial information for problem determination and resolution within the z/OS ecosystem.

Key Characteristics

- Message ID: Typically begins with a prefix (e.g., IEF, IKJ, IDC, IGZ) identifying the component or product that issued the message, followed by a numeric code and sometimes a suffix indicating severity or type.
- Severity Levels: Messages often include an indicator (e.g., I for informational, W for warning, E for error, S for severe, A for action required, D for decision required) to convey the criticality of the event.
- Diagnostic Information: Beyond the basic problem statement, messages frequently include variable data such as resource names, return codes, reason codes, module names, or addresses to aid in pinpointing the exact cause.
- Output Locations: Error messages can appear on the system console, in a job's SYSOUT (job log), in the SYSLOG, in application-specific logs, or within interactive terminal sessions (e.g., TSO/ISPF).
- Actionable Advice: Many messages, especially those requiring operator intervention, include suggested actions or references to documentation (e.g., "See message IGZ0001I in IBM COBOL for z/OS Messages and Codes").

Use Cases

- JCL Syntax or Execution Errors: Messages like IEF212I (DD statement missing) or S806 (module not found) indicate problems with JCL syntax, dataset allocation, or program loading.
- Application Program Failures (ABENDs): A COBOL program encountering a data exception might result in an OC4 abend, accompanied by messages detailing the program name, offset, and possibly the data involved.
- System Resource Issues: Messages such as IEC070I (device not ready) or IXG301I (log stream full) inform operators about hardware or system resource contention/failure.
- Utility Program Errors: An IDCAMS utility failing to define a VSAM dataset due to an invalid parameter will issue specific IDC messages detailing the error.
- Database System Errors: DB2 or IMS messages (e.g., DSNT500I for SQL errors, DFS042A for IMS transaction errors) indicate problems with database access, integrity, or availability.