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SINTRAN III NPL Source Code

This directory contains SINTRAN III operating system source code written in NPL (Norsk Data Programming Language).

Contents

Source Files

  • s3vs-4.symb (3.9 MB) - Original SINTRAN generation job output file containing the complete source code listing
  • NPL/ - Directory containing 45 individual NPL source files extracted from the SYMB file
  • SYMBOLS/ - Directory containing symbol tables for three SINTRAN III versions (K03, L07, M06)

NPL Subfolder Structure

The NPL/ subfolder contains the split-out source files from s3vs-4.symb, organized by component:

  • 0.SIN-GEN.NPL - SINTRAN generator/initialization
  • 5P-P2-MON60.NPL - Monitor/kernel code
  • CC-P2-*.NPL - Common compiler components
  • DP-P2-*.NPL - Data processing components
  • IP-P2-*.NPL - Input/output and device drivers (DISK, SCSI, SEGADM)
  • MP-P2-*.NPL - Memory and peripheral management (HDLC, ND-500, HASP)
  • TP-P2-*.NPL - Terminal and communication handling

SYMBOLS Subfolder - Multi-Version Symbol Tables

The SYMBOLS/ subfolder contains symbol tables for three SINTRAN III versions, organized into version-specific subfolders:

SYMBOLS/
├── J/      (5 files - SINTRAN III version J, from distribution floppies gen. 86-08-04)
├── K03/    (6 files - SINTRAN III version K, level 03)
├── L07/    (7 files - SINTRAN III version L, level 07)
└── M06/    (8 files - SINTRAN III version M, level 06)

The J/ set was extracted 2026-08-18 from the four original distribution floppies N-900-188-I..IV ("SINTRAN III VERSION J", MACM-1718, gen. date 86.08.04, on backup disk D:\ND\Frode), converted from ND 8-bit parity text to plain ASCII. It has no level number on the labels, so the folder is just J. It contains FILSYS-SYMBOLS, RTLO-SYMBOLS, SYMBOL-1-LIST, SYMBOL-2-LIST and LIBRARY-MARKS - no N500-SYMBOLS and no XMSG-SYMBOL-LIST were on the floppies. Its LIBRARY-MARKS first line matches the marks list in the version-J SI-GEN build log ../NPL-SOURCE-2/BOUT-6.SYMB word for word. The version-J NPL source that goes with these symbols is in ../NPL-SOURCE-2/.

The version naming convention uses a letter for the major version (K, L, M) and a number for the level within that version (03, 07, 06). These represent successive generations of SINTRAN III.

Symbol tables are reference files mapping variable names, procedure entry points, and constants to their memory addresses in octal. These symbols are critical for:

  • Understanding memory layout - Where kernel structures reside
  • Cross-referencing NPL code - Matching symbols to source code
  • Emulator development - Implementing correct memory addressing
  • Debugging - Resolving addresses to symbolic names

5-Character Symbol Name Limit

Due to 1980s memory constraints, symbol names are limited to a maximum of 5 characters. When cross-referencing NPL source code with symbol tables, only the first 5 characters of an NPL variable name should be used to find the matching symbol. A few exceptions exist in N500 symbol files (e.g., CNVBYADR, CNVWADR, FP2ENT).

Symbol Files Per Version

File K03 L07 M06 Category
FILSYS-SYMBOLS.SYMB.TXT 41 KB 61 KB 63 KB File system
LIBRARY-MARKS.SYMB.TXT 13 KB 14 KB 14 KB Library entry markers
N500-SYMBOLS.SYMB.TXT 64 KB 122 KB 123 KB ND-500 interface
N5000-SYMBOLS.SYMB.TXT - - 124 KB ND-5000 processor (M06 only)
RTLO-SYMBOLS.SYMB.TXT 48 KB 56 KB 57 KB Runtime library
SYMBOL-1-LIST.SYMB.TXT 76 KB 102 KB 105 KB Primary kernel
SYMBOL-2-LIST.SYMB.TXT 53 KB 69 KB 71 KB Secondary kernel
XMSG-SYMBOL-LIST.SYMB.TXT - 30 KB 36 KB XMSG messaging

Version Differences

  • K03: 6 files, no XMSG support
  • L07: 7 files, adds XMSG messaging system
  • M06: 8 files, adds N5000-SYMBOLS for the ND-5000 processor (distinct from ND-500)

Stable across versions: Structure offsets (queue heads, process fields, device fields, state bits) remain consistent across all three versions.

Changes between versions: Code addresses (e.g., ENDOP, CT500, SC100, RTBES) differ between versions due to kernel code growth.

Symbol File Categories

File Contents
SYMBOL-1-LIST Primary kernel - scheduler, system structures, ND-500 integration, error codes, device structures. Dominant prefixes: S (system/scheduler), 5 (ND-500), E (errors), D (device/disk)
SYMBOL-2-LIST Secondary kernel - device terminal pairs (DTxxR/DTxxW), device driver entries, configuration constants. Dominant prefix: D (665 symbols)
FILSYS-SYMBOLS File system structures - status/state, disk, allocation, memory. Dominant prefixes: S (status), D (disk)
N500-SYMBOLS ND-500 coprocessor interface - process management, memory, transport. Dominant prefixes: 5 (ND-500), T (transport/TAD)
N5000-SYMBOLS ND-5000 processor interface (M06 only). Different memory addresses than N500 for shared symbols
RTLO-SYMBOLS Runtime library entry points - PIT (Page Index Table) variants, user utilities. Multiple xPIT patterns
XMSG-SYMBOL-LIST XMSG inter-process messaging system (L07+). Not present in K03
LIBRARY-MARKS Loadable library entry markers using reversed format (175777/^NAME). Fixed address references

Note: While we don't have the complete file system source code, the FILSYS-SYMBOLS.SYMB.TXT files provide crucial reference information about file system data structures and entry points across all three SINTRAN versions.

Symbol File Format

Symbol files contain entries in the format: 

SYMBOLNAME=OCTAL_ADDRESS

Example from FILSYS-SYMBOLS.SYMB.TXT: 

UINDP=000003    ! User index pointer
DPAGA=153555    ! Data page address
UNLCQ=034062    ! Unlock queue
DATA=054400     ! Data segment base

Remember: Only the first 5 characters of a symbol name are significant when cross-referencing with NPL source code.

Using Symbol Tables

  1. Find kernel variables - Search symbol files for variable names mentioned in documentation
  2. Resolve addresses - Convert octal addresses to understand memory layout
  3. Map to source code - Cross-reference symbols with NPL source files (use first 5 chars only)
  4. Emulator verification - Validate emulator memory structures match SINTRAN layout
  5. Compare versions - Check how addresses change across K03/L07/M06

What is s3vs-4.symb?

The s3vs-4.symb file is the output of a SINTRAN generation job - a complete build listing that includes:

  1. Source code for kernel components
  2. Symbol tables and cross-references
  3. Compilation metadata
  4. Assembly listings

This SYMB file has been split into individual NPL source files for easier analysis and navigation. Each NPL file in the NPL/ subfolder represents one compilation unit from the original SINTRAN III system.

Coverage and Limitations

What's Included

This source code covers several critical SINTRAN III subsystems:

  • Kernel/Monitor (MON60) - Core OS services
  • Device Drivers - SCSI disk, HDLC communication, magnetic tape
  • Memory Management (SEGADM) - Segment administration
  • ND-500 Integration - 32-bit coprocessor interface
  • Disk I/O Subsystem - Disk startup and logging
  • HASP Protocol - Remote job entry

What's Missing

This is an incomplete source code collection. Major missing components include:

  • File system implementation (Level 11, directory management, file access)
  • Level 23 file system (symbolic files, directories)
  • Complete terminal handlers
  • Network subsystems (beyond HDLC drivers)
  • Batch processing components
  • Backup/restore utilities
  • System utilities and commands

The file system code is particularly significant because it represents a large portion of the SINTRAN III kernel that is not available in this collection.

NPL Language

NPL (Norsk Data Programming Language) is a systems programming language similar to ALGOL/Pascal, designed for:

  • Operating system development
  • Real-time systems
  • Low-level hardware access
  • Bit manipulation and memory control

Key NPL Characteristics

  • Strong typing with runtime checks
  • Direct memory addressing
  • Interrupt handling primitives
  • Hardware register access
  • Procedure-oriented with nested scopes
  • Assembler-like control over memory layout

NPL Resources

For NPL language reference and development guides, see:

How to Use This Source Code

1. Reading NPL Source Files

NPL files can be opened in any text editor. They contain:

  • Procedure declarations - PROCEDURE name;
  • Variable declarations - INTEGER var;, REF(type) ptr;
  • Control structures - IF...THEN...ELSE, WHILE...DO, FOR...DO
  • Assembly blocks - %ASSEMBLY_CODE% for direct machine code
  • Comments - ! for line comments, COMMENT ...; for block comments

2. Cross-Referencing with Documentation

This source code should be read alongside the kernel documentation:

3. Analyzing Specific Components

Component NPL Files Symbol Tables Documentation
SCSI Subsystem IP-P2-SCSI-*.NPL SYMBOLS/{version}/SYMBOL-1-LIST.SYMB.TXT SINTRAN/Devices/SCSI/
HDLC Driver MP-P2-HDLC-DRIV.NPL SYMBOLS/{version}/SYMBOL-1-LIST.SYMB.TXT SINTRAN/Devices/HDLC/
ND-500 Interface CC-P2-N500.NPL, MP-P2-N500.NPL SYMBOLS/{version}/N500-SYMBOLS.SYMB.TXT SINTRAN/ND500/
Disk Management IP-P2-DISK-.NPL, MP-P2-DISK-.NPL SYMBOLS/{version}/SYMBOL-1-LIST.SYMB.TXT SINTRAN/OS/15-DISK-IO-SUBSYSTEM.md
Segment Admin IP-P2-SEGADM.NPL SYMBOLS/{version}/SYMBOL-1-LIST.SYMB.TXT SINTRAN/OS/16-PAGE-FAULT-HANDLER.md
File System (source not available) SYMBOLS/{version}/FILSYS-SYMBOLS.SYMB.TXT SINTRAN/OS/
XMSG System (source not available) SYMBOLS/{version}/XMSG-SYMBOL-LIST.SYMB.TXT (L07+) SINTRAN/OS/14-MONITOR-KERNEL-MONCALLS.md

File Naming Convention

NPL source files follow the pattern: [Prefix]-P2-[Component].NPL

Prefix Meanings

  • 0 - System generation/initialization
  • 5P - Pass 5 (monitor/kernel)
  • CC - Common compiler components
  • DP - Data processing
  • IP - Input processing
  • MP - Main processing
  • TP - Terminal processing

P2 Designation

P2 indicates "Pass 2" of the SINTRAN build process - this is the code generation and linking phase that produces executable kernel code.

Extraction History

The NPL files in the NPL/ subfolder were extracted from s3vs-4.symb by:

  1. Identifying file boundaries in the SYMB listing
  2. Extracting individual compilation units
  3. Preserving original file names from the build job
  4. Maintaining source code formatting and comments

Original SYMB file: Preserved as-is for reference and verification Split files: Individual NPL files for easier navigation and analysis

Kernel Architecture

Device Drivers

ND-500 Coprocessor

Reference Manuals

Notes for Developers

Emulator Implementation

When implementing SINTRAN III behavior in the C# emulator:

  1. Read the NPL source first - Understand exact algorithm and data structures
  2. Cross-reference documentation - Verify understanding with kernel docs
  3. Match memory layouts - Use SINTRAN/OS/19-MEMORY-MAP-REFERENCE.md
  4. Preserve semantics - Keep SINTRAN behavior identical, even if inefficient

Source Code Authenticity

This source code is from a real SINTRAN III build job (s3vs-4). It represents production operating system code that ran on Norsk Data ND-100 computers in the 1980s.

Verification: All code can be traced to the original s3vs-4.symb file.

Status

Source Code Availability: Partial (kernel components only) File System Code: Missing (but symbols available in SYMBOLS/{version}/FILSYS-SYMBOLS.SYMB.TXT) Total NPL Files: 45 Symbol Table Versions: 3 (K03, L07, M06) Total Symbol Table Files: 21 files across 3 versions (~1.3 MB) Total Size: ~5.2 MB (SYMB file + all symbol tables)

Last Updated: 2026-02-08 SINTRAN Version: SINTRAN III Version 4 SINTRAN Levels: K03, L07, M06 (symbol tables for 3 versions) Build Job: s3vs-4