Assumptions and Dependencies

Assumptions, Dependencies, and Constraints

Field	Value
Document ID	PGCBL-SAD-002
Document Type	Assumptions, Dependencies, and Constraints Register
System	pgcobol — Prime Numbers Application v1.0
Version	1.0
Status	Draft — requires stakeholder confirmation
Owner	Lead Developer
Author	[reverse-engineered from source artifacts]
Created	2026-03-17
Last modified	2026-03-17
Classification	Internal
Parent document	PGCBL-BRD-001

Version History

Version	Date	Author	Status	Change Summary
0.1	2026-03-17	—	Draft	Derived from source analysis

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Table of Contents

1. Purpose
2. How to Use This Register
3. Assumptions
4. Dependencies
5. Constraints
6. Risk Summary
7. Open Issues

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1. Purpose

This register captures every assumption made during the design, every dependency the system relies on, and every constraint that limits the design space. It exists so that:

• If an assumption turns out to be wrong, the impact on the design can be assessed quickly.
• If a dependency is unavailable, the team knows what is blocked.
• Constraints are documented with their source, so they can be challenged if the source changes.

Items marked [UNCONFIRMED] were inferred from source code analysis and have not been verified with a stakeholder.

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2. How to Use This Register

Best practice — generic

An assumption is something the team believes to be true but has not verified. Every assumption carries a risk: if the assumption is wrong, some part of the design or implementation will fail. Good practice is to:

1. State the assumption precisely (not vaguely).
2. Identify who should confirm or refute it.
3. Assign a risk severity if the assumption is wrong.
4. Track confirmation explicitly — an unconfirmed assumption is a risk item.

A dependency is something external to the system that must exist or be in a known state for the system to function. Dependencies are not assumptions — they are facts that must be managed.

A constraint is a limit imposed from outside the design team (a regulation, a platform choice, a budget) that restricts what solutions are possible.

Severity scale

Severity	Meaning
High	If wrong/unmet, the system cannot run or produces incorrect results
Medium	If wrong/unmet, a feature is degraded or a workaround is needed
Low	If wrong/unmet, a minor inconvenience; easily remediated

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3. Assumptions

ID	Assumption	Confirmed by	Confirmed date	Severity if wrong	Status
A-01	Prime 2 is manually inserted into the database before the first generation run. The algorithm starts at candidate 3 and immediately calls next-divider (ident=2), which requires a row with ident=2 to exist.	[UNCONFIRMED]	—	High	Open
A-02	The primes table is empty at the start of a fresh generation run. No de-duplication logic exists in the INSERT path; re-running generation will insert duplicate primes.	[UNCONFIRMED]	—	High	Open
A-03	The asc_ident sequence is reset to 1 before each generation run (achieved by running reset-primes.sql). If the sequence is not reset, the ident values used by the divider lookup will be wrong.	[UNCONFIRMED]	—	High	Open
A-04	The working directory at runtime is writable by the process owner, so primes.prt can be created.	[UNCONFIRMED]	—	High	Open
A-05	GnuCOBOL 4.0 and the GixSQL pre-processor are installed and on PATH before compilation.	[UNCONFIRMED]	—	High	Open
A-06	PostgreSQL is running on localhost:5432 when any program that calls primes.cbl is executed.	[UNCONFIRMED]	—	High	Open
A-07	The PostgreSQL schema primes and the user primes_user exist and have been granted the necessary privileges before first run.	[UNCONFIRMED]	—	High	Open
A-08	The system is run by a single operator at a time; no concurrent execution is expected.	[UNCONFIRMED]	—	Medium	Open
A-09	The 132-character print record width matches the target printer or viewer.	[UNCONFIRMED]	—	Low	Open
A-10	primes_cbsql.out (the pre-compiler listing) is a historical artefact of an earlier version of primes.cbl and the primesdb connection alias it references is no longer active.	[UNCONFIRMED]	—	Medium	Open

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4. Dependencies

ID	Dependency	Type	Version required	Owner	Status
DEP-01	GnuCOBOL compiler	Build-time	4.0 or later	Developer environment	Must be installed
DEP-02	GixSQL pre-processor	Build-time	Compatible with GnuCOBOL 4.0	Developer environment	Must be installed
DEP-03	PostgreSQL server	Runtime	11 or later	DBA	Must be running on localhost:5432
DEP-04	primes database and schema	Runtime	—	DBA	Must exist; created by primes_schema.sql
DEP-05	primes_user account	Runtime	—	DBA	Must exist with INSERT, SELECT privileges on primes.primes
DEP-06	Writable working directory	Runtime	—	OS / operator	Needed for primes.prt
DEP-07	reset-primes.sql executed before each generation run	Operational	—	Operator	Required for idempotent generation
DEP-08	Prime 2 seeded in primes.primes before first generation	Operational	—	Operator	Required for divider lookup to work from candidate 3

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5. Constraints

ID	Constraint	Source	Impact
C-01	Target runtime is Linux only. SPECIAL-NAMES. CONSOLE IS scherm is platform-specific.	GnuCOBOL platform support	Cannot run on Windows or mainframe without porting
C-02	Database must be PostgreSQL. The connection string prefix pgsql:// and GixSQL dialect are PostgreSQL-specific.	GixSQL driver	Not portable to DB2, Oracle, or SQL Server without code changes
C-03	Upper generation limit is hard-coded at 999,999,999.	Source code primesgen.cbl line 91	Cannot be changed without recompilation
C-04	Database credentials are hard-coded in primes.cbl WORKING-STORAGE.	Source code; technical debt	Credential rotation requires recompilation and redeployment
C-05	Print record width is fixed at 132 characters.	primesui.cbl FD and table layout	Report format cannot be changed without recompiling primesui
C-06	The two operational modes (generate / report) are mutually exclusive per invocation.	primesmain.cbl EVALUATE structure	Cannot generate and report in the same run
C-07	GnuCOBOL 4.0-early-dev was used; behaviour may differ from stable GnuCOBOL 3.x.	Compiler listing header	Compatibility with stable GnuCOBOL releases unverified

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6. Risk Summary

Items with High severity that are still unconfirmed represent the greatest project risk:

Risk	Assumptions involved	Recommended action
Generation produces wrong results or crashes on fresh DB	A-01, A-02, A-03	Write a pre-run setup script and document it as a mandatory step
Program fails silently at runtime due to missing infrastructure	A-04, A-05, A-06, A-07	Add pre-flight checks to primesmain (file/DB accessibility tests)
Pre-compiler listing alias mismatch causes disconnect failure	A-10	Inspect current primes.cbl disconnect path and confirm alias is primes

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7. Open Issues

ID	Issue	Owner	Target	Status
OI-01	All assumptions are unconfirmed. A stakeholder/developer review session is needed to confirm or correct each one.	Lead Dev	—	Open
OI-02	No pre-run setup script exists. DEP-07 and DEP-08 are manual steps with no enforcement.	Developer	—	Open

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