Glossary Updates12 new terms added to the glossaries · October 2, 2026, 22:44 CEST
AI TechDocKnowledge

Glossary · Automation software engineering and architecture

Real-time software

Also known as: Real-time application

German: Echtzeitsoftware

In computing, real-time software is software whose correctness depends not only on its results but also on producing them within defined time limits.

  • Software engineering

In one sentence

Real-time software is correct only if it delivers the right results within defined time limits.

Example

The PLC program of a packaging machine must compute the cam positions within each 2 ms cycle; a late result is as wrong as a wrong result.

How it applies

  • Engineering: Timing requirements are specified like functional ones: period, deadline, maximum Latency and Jitter. Design avoids operations with unbounded duration, such as dynamic memory allocation in cyclic tasks.
  • Verification: Tests measure execution times on the target hardware; analysis of the Worst-case execution time (WCET) supports the claim that deadlines are always met.
  • Documentation: Technical data and system requirements should express real-time capabilities in measurable terms (cycle time, response time, conditions). Avoid the bare phrase real-time capable without figures.

Hard, firm and soft real time

In Hard real time, a missed deadline counts as a system failure. In firm real time, a late result is useless but occasional misses are tolerated. In Soft real time, late results lose value gradually.

By knowledge.aitechdoc.world · Published September 26, 2026 · Last reviewed

Source: AI TechDoc Knowledge editorial definition, based on real-time systems practice

Definitions follow the cited standards and specifications. Where a source is a copyrighted publication, such as an ISO, IEC or EN standard, the definition is a close paraphrase, not a verbatim quotation, so as not to infringe copyright. We recommend reading the original publication. The sections “How it applies” are editorial commentary by AI TechDoc Knowledge and are not part of any standard.

Seen a mistake? Send us a note!