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Jobname

Enhanced Definition

A `jobname` is a unique, 1-to-8 character identifier assigned to a batch job or a started task (STC) within the z/OS operating system. It serves as the primary means for z/OS, system operators, and system software to identify, track, and control a specific unit of work.

Key Characteristics

- Format: Consists of 1 to 8 alphanumeric characters (A-Z, 0-9, @, #, $). The first character must be alphabetic (A-Z) or one of the special characters (@, #, $).
- Uniqueness: Must be unique among all active jobs and started tasks within a single z/OS image or a JESplex (if using shared spool).
- Assignment: For batch jobs, it is specified as the first positional parameter on the JOB statement in Job Control Language (JCL). For started tasks, it is typically the member name of the procedure in a system procedure library (e.g., SYS1.PROCLIB).
- Visibility: Displayed prominently in system messages, operator consoles, job logs, and job management tools like SDSF (System Display and Search Facility).
- Scope: Its uniqueness is enforced at the system level for currently executing or held jobs.

Use Cases

- Job Submission: Specifying the jobname in the JOB statement when submitting a batch job via JCL.
- Job Monitoring: Operators and system programmers use the jobname to query the status of a job (e.g., DISPLAY A,L or using SDSF).
- Job Control: Issuing operator commands to control a specific job, such as CANCEL jobname, HOLD jobname, or REPLY jobname,response.
- Resource Management: Workload Manager (WLM) uses the jobname (among other criteria) to classify work and apply appropriate service goals and resource allocation.
- Security and Auditing: Security systems like RACF use jobname in profiles to control what resources a job can access or what programs it can execute, and it is a key field in system audit trails.

Related Concepts

The jobname is intrinsically linked to the JCL JOB statement, where it is the mandatory first parameter. It is a critical identifier used by JES (Job Entry Subsystem) to manage the job's lifecycle from submission to termination. In SDSF, jobname is a primary filter and display field for viewing job status, output, and resource consumption. Workload Manager (WLM) relies on jobname as a common classification criterion to ensure jobs receive appropriate system resources based on their importance.

Best Practices:

Meaningful Naming: Use descriptive jobnames that clearly indicate the job's purpose (e.g., PAYROLL01, DB2UTIL).
Standard Naming Conventions: Establish and enforce consistent jobname conventions across your enterprise to improve readability, management, and troubleshooting.
Avoid Special Characters: While allowed, minimize the use of @, #, $ in jobnames to prevent potential conflicts or confusion, especially in environments with mixed character sets or older utilities.
JESplex Uniqueness: In a JESplex environment, ensure that jobnames are unique across all connected z/OS images for active jobs to prevent conflicts and ensure proper job management.
Security Integration: Be mindful of how jobnames are used in security profiles; avoid using easily guessable jobnames for jobs that perform sensitive operations or have elevated privileges.