Replica Determinism via Fixed Time Intervals

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Solution Overview

Problem

In distributed real-time computer systems, achieving replica determinism is challenging due to differences in internal clock frequencies among node computers, leading to unpredictable results and the need for complex synchronization methods that increase development costs and risk of timing errors.

Innovation Solution

A time-optimal method is introduced to synchronize the internal state of all correct node computers at predefined real-time points by dividing physical time into equal intervals based on the slowest clock frequency, using waiting intervals to ensure determinism and fault tolerance, eliminating the need for explicit state synchronization in application software.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complex synchronization methods are used to achieve replica determinism, then determinism is improved, but device complexity and development costs increase

Engineering Contradiction:
Improvereplica determinismVSAvoidsynchronization method complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the parameter of time interval division from arbitrary or application-defined to fixed and uniform across all replicas. By establishing a global time reference that divides time into equal intervals for all nodes, the system achieves deterministic behavior without complex application-level synchronization logic.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a universal time reference system that serves all replicas simultaneously. The fixed time intervals are applied universally across the distributed system, providing a common temporal framework that eliminates the need for replica-specific synchronization mechanisms.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If explicit state synchronization is implemented in application software, then replica determinism is achieved, but development effort and costs increase

Engineering Contradiction:
Improvereplica determinismVSAvoiddevelopment effort
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent enables replicas to automatically synchronize their internal states through the fixed time interval mechanism without requiring explicit synchronization commands in application software. Each replica independently follows the global time reference and processes events at predetermined intervals, achieving self-synchronization.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent extracts the synchronization logic from application software and embeds it in the system infrastructure through fixed time intervals. This separation removes the burden of explicit state synchronization from application developers while maintaining deterministic behavior.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If waiting intervals are used to synchronize replicas, then determinism is improved, but loss of time increases

Engineering Contradiction:
Improvereplica determinismVSAvoidwaiting interval
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent uses periodic fixed time intervals as the basis for replica synchronization. Events are processed at regular, predetermined intervals across all replicas, creating a rhythmic, predictable execution pattern that minimizes unnecessary waiting while ensuring determinism.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent establishes the fixed time interval structure in advance before replica execution begins. By pre-defining when events should occur based on the global time reference, replicas can prepare and execute without ad-hoc waiting, reducing time loss while maintaining synchronization.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2592554B1Method for optimizing the waiting time in replica-deterministic systems
Publication Date: 2015.10.14 FTS - COMPUTERTECHNIK GES MBH
  • EP2592554B1 patent drawingFigure 1~2

AI summary

The replica-deterministic characteristics realization method involves connecting multiple of nodal computers (110,111,112) by a time-controlled real time communication system, where each nodal computer is equipped with a particular internal clock of a nominal frequency. The actual frequencies of the internal clock of the nodal computer move in an interval around the nominal frequency, where a defined inner state of the nodal computer is ensured for time point of the occurrence of periodical significant events (210,211,212) with the nominal real distance.