Version

Definition

A Version represents the state of an Artifact or Relation at a specific point in time.

Versions are immutable.

Once created, a Version never changes.

A new state always results in a new Version.

Motivation

Engineering knowledge evolves continuously.

Requirements change.

Designs mature.

Tests are improved.

Risks are reassessed.

Instead of overwriting previous information, ATON preserves the complete history.

Identity

Every Version has its own unique identifier.

A Version always belongs to exactly one Artifact or Relation.

Artifact
    │
    ├── Version 1
    ├── Version 2
    └── Version 3

The Artifact identity remains constant.

Versions describe its evolution.

Immutability

A Version cannot be modified.

If engineering knowledge changes, a new Version is created.

Version 1

↓

Version 2

↓

Version 3

This guarantees reproducibility and traceability.

Metadata

Each Version contains common metadata.

Examples include:

Version Number
Author
Timestamp
Commit Reference
Change Description

Capabilities may extend the metadata.

Lifecycle

Versions are created.

They are never deleted or modified.

Versions remain available for:

audits
reviews
baselines
traceability
historical analysis

Reviews

Reviews always reference a specific Version.

A Review never approves an Artifact in general.

It approves a particular Version.

Requirement

↓

Version 7

↓

Approved

If Version 8 is created, it requires a new Review.

Relations

Relations are versioned in the same way as Artifacts.

Changing a Relation creates a new Relation Version.

Traceability therefore has a complete history.

Baselines

Baselines consist of Versions.

They never reference mutable Artifacts.

Baseline 1

Requirement v4

Architecture v7

Test Case v2

Risk v5

A Baseline therefore represents a reproducible engineering state.

Git Integration

ATON does not replace Git.

Git stores the history of persisted engineering knowledge.

The Version model defines the engineering semantics.

Both complement each other.

Design Principles

A Version

is immutable
belongs to exactly one Artifact or Relation
records a historical state
can be reviewed
can belong to one or more Baselines
is fully traceable

Summary

Versions preserve the evolution of engineering knowledge.

History is never overwritten.

Engineering is a sequence of Versions.

Definition​