3 ms·
Ask HN: What do you consider real-time?
Forget the marketing-speak, curious to see what formal definitions are used. Are these typically system response latency cutoffs that vary by industry? ie. 1 second would not be real-time for algo trading, but might be for tweet aggregation for brands
- jsegura 10y agoIf we speak about human interactions, I think that it should be less than 250ms. In 1968 Robert Miller published his classic paper Response time in man-computer conversational transactions in which he described three different orders of magnitude of computer mainframe responsiveness: - A response time of 100ms is perceived as instantaneous. - Response times of 1 second or less are fast enough for users to feel they are interacting freely with the information. - Response times greater than 10 seconds completely lose the user’s attention. But I totally agree with you, it totally depends on what is the purpose of your system.
- sebleon 10y agoGood point, I wish this was better understood by the engineers at Gmail
- ankurdhama 10y agoShould be done in enough time to be useful.
- devnonymous 10y agoHistorically speaking real time was not actually about absolute timing but the guarantee offered about a task's completion within a time slice. More info here: https://en.m.wikipedia.org/wiki/Real-time_computing#Criteria_for_real-time_computing https://en.m.wikipedia.org/wiki/Real-time_computing#Criteria... Also look up RISC and RTOS
- brudgers 10y agoMy relatively non-formally informed opinion is that one property that seems to correlate with real time is: R ≤ S Where R is the maximum time it takes to return a useful result and S is the maximum sample rate. Anything else suggests that results queue up and hence the time to return a result varies.