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CICS FREE (MRO) - MRO Resource Deallocation

CICS FREE (MRO) provides MRO resource deallocation capabilities for programs and transactions. It enables programs to free MRO resources, manage MRO resource cleanup, and handle MRO resource deallocation in CICS environments.

What is CICS FREE (MRO)?

CICS FREE (MRO) is a command that allows programs to deallocate MRO resources in the system. It provides MRO resource deallocation capabilities, MRO resource cleanup, and MRO resource management for CICS applications.

Command Syntax

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EXEC CICS FREE
    MRO
    [RESP(response-code)]
END-EXEC

Parameters

Required Parameters

  • MRO - MRO resource type

Optional Parameters

  • RESP(response-code) - Response code variable

MRO Resource Types

MRO Sessions

MRO session resource types

  • • MRO SESSION - MRO session resources
  • • MRO CONVERSATION - MRO conversation resources
  • • MRO CONNECTION - MRO connection resources
  • • MRO CHANNEL - MRO channel resources

MRO Resources

MRO resource types

  • • MRO MEMORY - MRO memory resources
  • • MRO BUFFER - MRO buffer resources
  • • MRO QUEUE - MRO queue resources
  • • MRO EVENT - MRO event resources

MRO Communication

MRO communication resource types

  • • MRO MESSAGE - MRO message resources
  • • MRO DATA - MRO data resources
  • • MRO CONTROL - MRO control resources
  • • MRO STATUS - MRO status resources

MRO System

MRO system resource types

  • • MRO PROCESS - MRO process resources
  • • MRO THREAD - MRO thread resources
  • • MRO LOCK - MRO lock resources
  • • MRO HANDLE - MRO handle resources

Programming Examples

Basic MRO Resource Deallocation

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       IDENTIFICATION DIVISION.
       PROGRAM-ID. FREEMRO.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  RESPONSE-CODE PIC S9(8) COMP.
       
       PROCEDURE DIVISION.
           DISPLAY 'Freeing MRO resource'
           
           EXEC CICS FREE
               MRO
               RESP(RESPONSE-CODE)
           END-EXEC
           
           IF RESPONSE-CODE = DFHRESP(NORMAL)
               DISPLAY 'MRO resource freed successfully'
           ELSE
               DISPLAY 'MRO resource free failed'
           END-IF
           
           EXEC CICS RETURN END-EXEC.

Advanced MRO Resource Management

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       IDENTIFICATION DIVISION.
       PROGRAM-ID. FREEMRO2.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  RESPONSE-CODE PIC S9(8) COMP.
       01  FREE-COUNT PIC S9(2) COMP VALUE 0.
       01  MAX-FREES PIC S9(2) COMP VALUE 3.
       01  MRO-STATUS PIC X(1).
       01  MRO-RESOURCE-TYPE PIC X(8).
       
       PROCEDURE DIVISION.
           PERFORM INITIALIZE-MRO-RESOURCES
           PERFORM FREE-MRO-RESOURCES
           
           EXEC CICS RETURN END-EXEC.
       
       INITIALIZE-MRO-RESOURCES.
           MOVE 'SESSION' TO MRO-RESOURCE-TYPE.
       
       FREE-MRO-RESOURCES.
           PERFORM VARYING FREE-COUNT FROM 1 BY 1
               UNTIL FREE-COUNT > MAX-FREES
               
               PERFORM FREE-MRO-SINGLE-RESOURCE
               
               IF RESPONSE-CODE = DFHRESP(NORMAL)
                   MOVE 'F' TO MRO-STATUS
                   DISPLAY 'MRO resource ' FREE-COUNT ' freed successfully'
               ELSE
                   MOVE 'E' TO MRO-STATUS
                   DISPLAY 'MRO resource ' FREE-COUNT ' free failed'
               END-IF
           END-PERFORM.
       
       FREE-MRO-SINGLE-RESOURCE.
           EXEC CICS FREE
               MRO
               RESP(RESPONSE-CODE)
           END-EXEC.

Error Handling with MRO Resource Deallocation

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       IDENTIFICATION DIVISION.
       PROGRAM-ID. FREEMRO3.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  RESPONSE-CODE PIC S9(8) COMP.
       01  RETRY-COUNT PIC S9(2) COMP VALUE 0.
       01  MAX-RETRIES PIC S9(2) COMP VALUE 3.
       01  MRO-FREE-SUCCESSFUL PIC X(1) VALUE 'N'.
       
       PROCEDURE DIVISION.
           PERFORM FREE-MRO-RESOURCE-WITH-RETRY
           
           EXEC CICS RETURN END-EXEC.
       
       FREE-MRO-RESOURCE-WITH-RETRY.
           PERFORM FREE-MRO-RESOURCE
           
           IF RESPONSE-CODE NOT = DFHRESP(NORMAL)
               AND RETRY-COUNT < MAX-RETRIES
               ADD 1 TO RETRY-COUNT
               DISPLAY 'Retry ' RETRY-COUNT ' MRO resource free operation'
               PERFORM FREE-MRO-RESOURCE-WITH-RETRY
           END-IF.
       
       FREE-MRO-RESOURCE.
           EXEC CICS FREE
               MRO
               RESP(RESPONSE-CODE)
           END-EXEC
           
           EVALUATE RESPONSE-CODE
               WHEN DFHRESP(NORMAL)
                   MOVE 'Y' TO MRO-FREE-SUCCESSFUL
                   DISPLAY 'MRO resource free operation successful'
               WHEN DFHRESP(NOTAUTH)
                   DISPLAY 'Not authorized to free MRO resource'
               WHEN DFHRESP(INVREQ)
                   DISPLAY 'Invalid MRO resource free request'
               WHEN DFHRESP(RESOURCEERR)
                   DISPLAY 'MRO resource free operation error'
               WHEN DFHRESP(RESOURCENOTFOUND)
                   DISPLAY 'MRO resource not found'
               WHEN DFHRESP(RESOURCEINUSE)
                   DISPLAY 'MRO resource is in use'
               WHEN OTHER
                   DISPLAY 'Unexpected MRO resource free error'
           END-EVALUATE.

MRO Resource Management

MRO Resource Deallocation

  • • MRO Resource Free - Free allocated MRO resources
  • • MRO Resource Cleanup - Clean up MRO resource state
  • • MRO Resource Validation - Validate MRO resource state
  • • MRO Resource Monitoring - Monitor MRO resource status

MRO Resource Lifecycle

  • • MRO Resource Allocation - Allocate MRO resources
  • • MRO Resource Usage - Use allocated MRO resources
  • • MRO Resource Deallocation - Deallocate MRO resources
  • • MRO Resource Cleanup - Clean up MRO resources

MRO Resource Monitoring

  • • MRO Resource Tracking - Track MRO resource usage
  • • MRO Resource Auditing - Audit MRO resource operations
  • • MRO Resource Reporting - Report MRO resource status
  • • MRO Resource Analysis - Analyze MRO resource patterns

MRO Error Recovery

  • • MRO Error Detection - Detect MRO resource errors
  • • MRO Error Recovery - Recover from MRO resource errors
  • • MRO Retry Mechanisms - Implement MRO retry logic
  • • MRO Fallback Procedures - Use MRO fallback procedures

Error Handling

Common Response Codes

  • DFHRESP(NORMAL) - MRO resource free operation successful
  • DFHRESP(NOTAUTH) - Not authorized to free MRO resource
  • DFHRESP(INVREQ) - Invalid MRO resource free request
  • DFHRESP(RESOURCEERR) - MRO resource free operation error
  • DFHRESP(RESOURCENOTFOUND) - MRO resource not found
  • DFHRESP(RESOURCEINUSE) - MRO resource is in use

Performance Considerations

MRO Resource Efficiency

  • • Optimize MRO resource operations - Use efficient MRO resource handling
  • • Minimize MRO resource overhead - Reduce MRO resource processing overhead
  • • Use MRO resource pooling - Implement MRO resource pooling
  • • Monitor MRO resource frequency - Track MRO resource free patterns

System Impact

  • • Monitor system impact - Track how MRO resource free affects the system
  • • Optimize MRO resource handling - Ensure efficient MRO resource processing
  • • Manage MRO resource usage - Monitor MRO resource consumption
  • • Track performance metrics - Monitor MRO resource handling performance

Best Practices

MRO Resource Deallocation Best Practices

  • • Free MRO resources as soon as they are no longer needed
  • • Implement proper error handling for MRO resource operations
  • • Validate MRO resource state before freeing
  • • Use appropriate MRO resource management techniques
  • • Monitor MRO resource deallocation activities and performance
  • • Maintain MRO resource deallocation audit trails
  • • Handle MRO resource deallocation errors gracefully

Explain It Like I'm 5 Years Old

Think of CICS FREE (MRO) like putting away your MRO toys:

  • • Finished Playing: "You finished playing with your MRO toys" - MRO resource no longer needed
  • • Put Away: "Put your MRO toys away" - Free MRO resource
  • • Clean Up: "Clean up your MRO toy area" - MRO resource cleanup
  • • Room Clean: "Your MRO toy area is clean now" - MRO resource freed
  • • Keep Clean: "Keep your MRO toy area clean" - MRO resource management

Exercises

Exercise 1: Basic MRO Resource Deallocation

Create a program that frees a basic MRO resource.

Exercise 2: Advanced MRO Resource Management

Write a program that manages multiple MRO resource deallocations.

Exercise 3: Error Handling

Implement comprehensive error handling for MRO resource deallocation failures.

Related Concepts

MRO Resource Management

Managing MRO system resources

MRO Resource Deallocation

Deallocating MRO resources

MRO Resource Monitoring

Monitoring MRO resource usage

MRO Resource Cleanup

Cleaning up MRO resources

Error Handling

Managing MRO resource errors