olemus
aeg, mille kestel seade või süsteem on töövõimeline,
vastand on rikkeaeg;
töövõimelisus ei tarvitse aga tähendada käideldavust

Merriam-Webster:
time during which a piece of equipment (such as a computer) is functioning or able to function
// At the same time, network professionals must ensure their networks provide 99.99% uptime without additional financial resources or headcount to cover the complexities.

ülevaateid
https://www.techopedia.com/definition/9868/uptime

https://en.wikipedia.org/wiki/Uptime

https://smartbear-cc.force.com/portal/KbArticleViewer?name=Uptime-vs-Availability&sp=alertsite

vt ka
- aktiivaeg