APPLYCHECK

Enhanced Definition

`APPLYCHECK` is an SMP/E (System Modification Program/Extended) command option that simulates the application of a software modification (SYSMOD), such as a PTF or APAR, to a z/OS system's target libraries without making any permanent changes. Its primary purpose is to verify all prerequisites, co-requisites, and detect potential conflicts or missing components before a real `APPLY` operation.

Key Characteristics

- Simulation Mode: Performs a dry run of the APPLY process, reporting on what *would* happen without actually modifying any libraries or SMP/E zones.
- Dependency Checking: Verifies that all required SYSMODs (prerequisites) are present and that no conflicting SYSMODs (co-requisites) are installed.
- Error and Warning Reporting: Generates a detailed report in the SYSPRINT output, highlighting any issues such as missing SYSMODs, HOLDDATA conditions, module conflicts, or insufficient space.
- No Permanent Changes: Crucially, APPLYCHECK does not update target libraries, distribution libraries, or the SMP/E global zone, making it a safe diagnostic tool.
- HOLDDATA Evaluation: Checks for HOLDDATA entries associated with the SYSMODs being processed, which might indicate critical actions or conditions that need to be addressed.
- SMP/E Specific: This command option is exclusive to the SMP/E utility, which is the standard tool for installing and maintaining IBM and vendor software on z/OS.

Use Cases

- Pre-Installation Verification: Running APPLYCHECK before applying any critical PTF or APAR to a production z/OS system to ensure all dependencies are met and no conflicts exist, minimizing downtime.
- Impact Analysis: Assessing the potential impact of a large set of SYSMODs or a new product installation on existing software components and identifying any required prerequisite maintenance.
- Troubleshooting Failed Applies: Diagnosing why a previous actual APPLY command might have failed by first performing an APPLYCHECK to pinpoint specific missing components or conflicts.
- Planning Maintenance Windows: Using the APPLYCHECK output to determine the exact SYSMODs that will be applied and any HOLDDATA actions required, aiding in the planning of maintenance tasks.

Related Concepts

APPLYCHECK is an essential part of the SMP/E (System Modification Program/Extended) lifecycle, specifically related to the APPLY command. It operates on SYSMODs (System Modifications), which include PTFs (Program Temporary Fixes) and APARs (Authorized Program Analysis Reports). It relies heavily on the metadata stored within the SMP/E zones (Global, CSI, Target, Distribution), particularly the CSI (Consolidated Software Inventory) data, to perform its dependency and conflict checks. It is often used in conjunction with ACCEPTCHECK for a full verification cycle before making changes permanent in both target and distribution libraries.

Best Practices:

Always Precede APPLY with APPLYCHECK: Make it a standard practice to run APPLYCHECK before every actual APPLY command, especially in production or critical test environments, to prevent unexpected issues and system instability.
Thoroughly Review SYSPRINT Output: Carefully examine the APPLYCHECK output and SYSPRINT for any warnings, errors, or HOLDDATA conditions. Do not proceed with the actual APPLY until all reported issues are understood and addressed.
Address HOLDDATA Conditions: Pay close attention to HOLDDATA entries, particularly SYSTEM, DOC, and ACTION holds, as they often indicate critical actions required before or after applying a SYSMOD, such as IPLs, manual steps, or documentation updates.
Automate in Maintenance Scripts: Incorporate APPLYCHECK into automated maintenance scripts or JCL procedures to ensure consistent, reliable, and error-free software updates across all z/OS environments.
Combine with ACCEPTCHECK for Full Verification: For a complete verification cycle, especially when preparing for a new release or major update, consider using ACCEPTCHECK after a successful APPLY (or APPLYCHECK) to verify the distribution libraries as well.

The term "APROPOS" (meaning "relevant or appropriate") is a general English word and does not have a specific, technical meaning or usage within the IBM mainframe, z/OS, COBOL, JCL, CICS, DB2, or IMS ecosystem.

Therefore, it cannot be defined with the requested mainframe-specific "Key Characteristics," "Use Cases," "Relationship to Other Concepts," or "Best Practices" as a technical term within this context.

This glossary is designed for mainframe and z/OS technologies, focusing on terms that have a distinct technical definition and application within that environment. "APROPOS" does not fit this criterion.