# Availability
## MicroSim spec
- **Recommended sim type:** uptime / queue
- **Microsimmability score:** 91/100
- **Layout:** drawing region (canvas) on top; control region (sliders/buttons) below.
### Parameters (tunable controls)
- `MTBF`
- `MTTR`
- `Repair crews`
### What animates
A system blinks between up and down states as MTBF and MTTR change; the steady-state availability gauge converges live.
### Learning objective
Relate availability to MTBF, MTTR, and repair capacity.
## Links (Wikipedia order)
<!-- injected from _registry/childlinks/Availability.json (2026-07-30T02:09:12Z) -->
`Availability_factor` · `Availability_heuristic` · `Available_(disambiguation)` · `Copyright_status_of_works_by_the_federal_government_of_the_United_States` · `Corrective_maintenance` · [[Dependability]] · `Downtime` · `Fault_reporting` · `General_Services_Administration` · `Generating_Availability_Data_System` · `High_availability` · `List_of_system_quality_attributes` · `MIL-STD-188` · `Mean_time_between_failures` · `Mean_time_to_repair` · `North_American_Electric_Reliability_Corporation` · `Optimal_maintenance` · `Power_station` · `Reliability_block_diagram` · [[Reliability_engineering]] · [[Safety_engineering]] · `Spare_part` · `Spurious_trip_level` · [[System]] · [[Systems_engineering]] · `Uptime`
## From the Real GENERATIVE library
*Availability — placed from the Real G.E.N.E.R.A.T.I.V.E. course library (Engineering room). Source: Wikimedia Commons (via Wikipedia article media). [Details & license](https://commons.wikimedia.org/wiki/File:Series_vs_parallel_components.png).*
> In reliability engineering, the term availability has the following meanings: ([Wikipedia](https://en.wikipedia.org/wiki/Availability))
<!-- REAL-GENERATIVE-MEDIA:END -->
> p5.js MicroSim stub · part of System Quality Attributes · [Wikipedia source](https://en.wikipedia.org/wiki/Availability)
> Relation: subfield of system quality attributes.
## Concept summary
Availability is the fraction of time a [[System|system]] is operational and accessible, governed by mean time to failure and mean time to repair.
## Build checklist
- [ ] Claim it: set `status: in-progress` + `lease` + `leased_at`
- [ ] Write the child page explaining the concept (tie it back to system quality attributes)
- [ ] Finalize parameter ranges and defaults
- [ ] Implement the p5.js sketch (drawing + control regions)
- [ ] Add caption + the learning objective on the page
- [ ] Set `status: done`
## p5.js sketch
```javascript
// MicroSim: Availability
let controls = {};
function setup() {
// createCanvas(...); create sliders for the parameters above.
}
function draw() {
// background(...); read controls; render uptime / queue; respond live.
}
```
---
Back to System Quality Attributes · Wikipedia: [Availability](https://en.wikipedia.org/wiki/Availability)
---
<!-- SEMIOTIC-PROFILE:START -->
## Semiotic profile
> *The semiotic universals this article invokes, machine-derived from the crossref — **unverified** (born so). Populated 2026-07-06 for the Systems room.*
**Universals (2):** 🟡 system (15) · 🟢 equilibrium (1)
**Enter by sign:** Systems Semiotic Gateway · Alphabetum · Icon Registry · ← Systems Portal
<!-- SEMIOTIC-PROFILE:END -->
<!-- REAL-GENERATIVE-MEDIA:START -->
## Wikipedia : Wikitube
**Strict pair:** [Wikipedia](https://en.wikipedia.org/wiki/Availability) : [Wikitube](https://en.wikitube.io/wiki/Availability)
## Previous hub tags
Tree parents: [[Reliability_engineering]] · [[Systems_engineering]].
Legacy hubs: none.
---
*Sources: 2 legacy notes. Minted wave 1, 2026-07-30 (v1.6 order).*