Business Requirement Document

Business Requirements Document

Field	Value
Document ID	PGCBL-BRD-001
Document Type	Business Requirements Document
System	pgcobol — Prime Numbers Application v1.0
Version	1.0
Status	Approved
Owner	Lead Developer
Author	[reverse-engineered from source artifacts]
Reviewers	— (pending)
Approved by	— (pending)
Created	2026-03-17
Last modified	2026-03-17
Classification	Internal
Parent document	PGCBL-SAD-001 (Scope and Applicability)
Supersedes	—

Version History

Version	Date	Author	Status	Change Summary
0.1	2026-03-17	—	Draft	Initial reverse-engineering baseline
1.0	2026-03-17	—	Approved	Baselined

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Table of Contents

1. Purpose and Scope
2. Assumptions and Dependencies
3. Stakeholders
4. Functional Requirements
5. Non-Functional Requirements
6. Constraints
7. Out of Scope
8. Related Documents
9. Open Issues

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1. Purpose and Scope

1.1 Purpose

This document defines what the pgcobol system must do from a business perspective. It is the primary input to all technical and design documents in the specification set. Any feature not described here is out of scope.

1.2 Scope

This document covers all externally observable behaviour of pgcobol v1.0: prime-number generation, database persistence, and printed report production.

1.3 Out of Scope

• How the system achieves its requirements (that is PGCBL-TSD-001).
• Internal program structure and algorithm details (PGCBL-PLG-001).
• Non-functional quality attributes in detail (PGCBL-NFR-001).

1.4 Audience

Business analysts, QA engineers, and stakeholders who need to understand what the system does without needing to read COBOL.

1.5 Related Documents

Document ID	Title	Relationship
PGCBL-SAD-001	Scope and Applicability	Navigation; defines document set
PGCBL-NFR-001	Non-Functional Requirements	Complements this BRD with quality attributes
PGCBL-TSD-001	Technical Specification	Implements requirements in this document
PGCBL-TTM-001	Test Traceability Matrix	Maps each requirement here to a test case
PGCBL-ADD-001	Architecture Decision Records	Documents why the design is as it is

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2. Assumptions and Dependencies

See PGCBL-SAD-002 for the full register. Key items:

ID	Item	Type
A-01	Prime 2 is manually seeded in the DB before generation	Assumption
A-02	DB is empty at the start of a generation run	Assumption
DEP-03	PostgreSQL running on localhost:5432	Dependency
DEP-08	Prime 2 seeded before first generation	Dependency

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3. Stakeholders

Role	Interest
System operator	Runs generation and reporting jobs from the command line
Database administrator	Owns the PostgreSQL schema; manages credentials and data
Report consumer	Reads the formatted print file primes.prt

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4. Functional Requirements

FR-01 — Prime Generation

• The system shall accept a generate command-line argument to trigger prime-number generation.
• The system shall test every odd integer from 3 upward for primality using trial division.
• The system shall store each confirmed prime in the database in ascending order of discovery.
• Generation shall continue until the candidate number reaches 999,999,999.

FR-02 — Trial-Division Algorithm Correctness

• For each candidate number N, the system shall divide N by each known prime p where p ≤ √N.
• If any p divides N exactly (remainder = 0), N is composite and shall not be stored.
• If no p ≤ √N divides N, N is prime and shall be persisted.

FR-03 — Prime Reporting

• The system shall accept a report command-line argument to trigger report generation.
• The system shall read all stored primes from the database in sequence order.
• The system shall write a paginated, formatted print file containing all primes.

FR-04 — Print Report Format

• The report shall contain a page heading (“primes overview”) and column headers on each page.
• Each data line shall display six prime entries side by side: sequence number and prime value.
• Each page shall carry a page-number footing.
• The print record width shall be 132 characters.
• The report shall be written to a file named primes.prt.

FR-05 — Operational Logging

• The system shall write progress and status messages to the system console throughout execution.
• Each message shall identify the issuing program name and paragraph.

FR-06 — Error Handling

• The system shall log an error message and stop cleanly if an unrecognised command-line argument is provided.
• The system shall log an error message and stop cleanly if the print file cannot be opened.
• The system shall log database connection or cursor failures and set an error indicator before exiting.

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5. Non-Functional Requirements

Summary only — see PGCBL-NFR-001 for full specification.

ID	Category	Requirement
NFR-PERF-01	Performance	≥ 1,000 primes generated per second
NFR-REL-01	Reliability	Batch runs to completion without manual intervention
NFR-SEC-01	Security	No credentials in compiled binary
NFR-MAIN-01	Maintainability	SQL only in primes.cbl; file I/O only in primesui.cbl
NFR-OPER-02	Operability	Non-zero process return code on failure

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6. Constraints

ID	Constraint
C-01	Must run on Linux with GnuCOBOL 4.0
C-02	Must use PostgreSQL as the database
C-03	Upper generation limit: 999,999,999 (hard-coded)
C-04	Single-user batch execution only

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7. Out of Scope

• Interactive or web-based user interfaces.
• Concurrent or distributed execution.
• Generation of prime numbers by any algorithm other than trial division.
• Any prime number below 2 or above 999,999,999.
• Checkpoint/restart capability for interrupted generation runs.

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8. Related Documents

As listed in §1.5.

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9. Open Issues

ID	Issue	Owner	Target	Status
OI-01	FR-01: generate loop is commented out in current source — this is defect D-01. FR-01 is not fully met by the current code.	Developer	—	Open
OI-02	FR-06: the process does not return a non-zero exit code on error (NFR-OPER-02 gap).	Developer	—	Open

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