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Capability

System Health & Resilience

Keep system condition visible.

Evidence levelE0Concept

Discuss Resilience Requirements

The functional gap

A system that hides its own faults makes every answer look healthier than it is. A reader has to see the state of the system alongside the state of the sky.

From inputs to outputs

Takes in

  • The condition of each source and link
  • The age of the data in each path
  • Faults and recoveries as they happen

Does

Reports the health of the system as part of the picture, steps down what it claims when a part fails, and says what was lost.

Hands on

  • Health shown beside every state
  • Claims that step down as sources are lost
  • A plain statement of what is degraded
Conceptual timing band: Data table
ItemValue
Timing bandField
Conceptual timing band RD02Data status: IllustrativeEvidence level: E0 · ConceptQuestion answered: How does sensing unfold over timeA fixed arc band fades in twice across a field and then stays still. It illustrates sensing over time in general terms and never turns or follows an object.Limitation: A general illustration of timing. It does not depict passive coherent location or any real sensor.

A worked example

Three steps from a synthetic scenario, in relative terms.

A worked example Synthetic example
StepWhat is seenWhat is stated
1All sources reportStates are stated at full strength
2One source stops reportingThe state is stated more cautiously, with the reason
3The source recoversThe claim returns and the interruption stays on record
  • Normal
  • Degraded
  • Unavailable
System health over time: Data table
Time (relative)Component 1Component 2Component 3
1NormalNormalNormal
2NormalNormalNormal
3NormalNormalNormal
4NormalNormalUnavailable
5NormalNormalUnavailable
6NormalDegradedNormal
7NormalDegradedNormal
8DegradedNormalNormal
9DegradedNormalDegraded
10NormalNormalNormal
11NormalNormalNormal
12NormalNormalNormal
System health over time CH07Data status: Synthetic dataEvidence level: E0 · ConceptQuestion answered: How has system health changed?Three bands, one for each of three example components, show normal, degraded and unavailable periods as different fills and patterns, so state never depends on colour alone.Limitation: Periods are invented and say nothing about any real component.

Confidence and uncertainty in this function

System health is an input to confidence, so a degraded system states less, and says why, before anyone has to ask.

Evidence and maturity

This page claims nothing above the level of the projects it rests on.

Where it applies

What this does not claim

  • Resilience is described as a design goal; no availability or recovery figure is stated.
  • The page shows no real fault history and no real system.
  • A healthy system does not make every answer right.

Projects behind this

Technology