CICS Without RESP/RESP2

Why environment-dependent error paths collapse determinism — and why authority must refuse.

This analysis is part of the Legacy Lens research pillar: Why Mainframe Modernization Fails .

What RESP and RESP2 Do in CICS

In CICS, the RESP and RESP2 options capture execution status for CICS commands.


EXEC CICS
  READ FILE(ACCTFILE)
  INTO(WS-ACCT-REC)
  RESP(WS-RESP)
  RESP2(WS-RESP2)
END-EXEC
    

These fields allow the program to branch explicitly based on success, recoverable error, or system failure.

The Problem: Missing RESP/RESP2

Many legacy COBOL programs invoke CICS commands without capturing RESP or RESP2.


EXEC CICS
  READ FILE(ACCTFILE)
  INTO(WS-ACCT-REC)
END-EXEC
    

In this case, error handling is delegated to the CICS environment, not expressed in source code.

Why This Breaks Determinism

When RESP/RESP2 is omitted, runtime behavior depends on:

None of these are derivable from COBOL source artifacts.

Two environments running identical code may exhibit different behavior for the same error condition.

Why Testing Is Not Evidence

It is common to hear:

These statements describe observed behavior, not provable guarantees.

Authority cannot rely on environmental assumptions that are not encoded in source artifacts.

CICS Migration Failure Modes

When CICS programs without RESP handling are migrated, common failure modes include:

These failures often emerge only after traffic patterns or error rates change.

Why Authority Must Refuse

Issuing a GO decision would require assuming that the execution environment enforces specific, consistent error semantics.

That assumption is not provable from source.

Under Production · Regulated · High governance context, missing RESP/RESP2 therefore terminates authority.

Related provability boundaries include dynamic CALL resolution and ALTER control-flow mutation.

What Institutions Do When This Appears

Institutions typically respond by:

  1. Refactoring to explicit RESP/RESP2 handling
  2. Isolating CICS interactions behind wrappers
  3. Documenting refusal and proceeding with partial scope

How This Research Is Used in Governance

Authority records cite this page as the public definition of why CICS commands without RESP handling terminate deterministic guarantees.

This ensures refusals are consistent, auditable, and defensible years later.

Explicit Non-Claims

This article describes general provability boundaries associated with missing CICS RESP/RESP2 handling. It does not analyze any specific institution’s code and does not issue a governance decision.

This analysis is part of the Legacy Lens research pillar: Why Mainframe Modernization Fails .