HH - Hour

Enhanced Definition

`HH` is a common two-digit representation for the hour component of a time or timestamp, typically following a 24-hour clock format (00-23). In mainframe systems, it is widely used in data fields, programming constructs, and system utilities to specify or display time.

Key Characteristics

- 24-Hour Format: Represents hours from 00 (midnight) to 23 (11 PM), eliminating the need for AM/PM indicators.
- Two-Digit Representation: Always uses two digits, with a leading zero for single-digit hours (e.g., 01 for 1 AM, 13 for 1 PM).
- Numeric or Character: Can be stored as a numeric value (e.g., packed decimal, zoned decimal) or as a character string, depending on the application and data type definition.
- Integral Part of Timestamps: Frequently combined with year, month, day, minute, second, and millisecond components to form complete timestamps (e.g., YYYYMMDDHHMMSS).
- System-Wide Usage: Employed across various z/OS components, including JCL, COBOL, DB2, CICS, and system logs.

Use Cases

- Timestamp Generation and Storage: Used in YYYYMMDDHHMMSS or YYYY-MM-DD HH:MM:SS formats for recording when events occurred in databases (e.g., DB2 TIMESTAMP columns), logs, and audit trails.
- JCL Parameters: While TIME= on the JOB statement typically specifies CPU minutes, HH is an implicit part of broader time-related constructs used for job scheduling or dataset expiration.
- COBOL Program Logic: Used in ACCEPT ... FROM TIME statements to retrieve the current hour, or as a component of PIC 99 or PIC X(02) data items for storing and manipulating time values within applications.
- Scheduling and Automation: Defines specific hours for batch job execution, report generation, or system maintenance tasks using workload schedulers like TWS (Tivoli Workload Scheduler) or CA-7.
- Performance Monitoring and Reporting: Displays the hour in performance metrics, resource utilization reports, and system console messages to indicate when specific events or thresholds were met.