4 ms·

That depends on whether we're talking about hard-realtime or soft-realtime. [0] https://www.google.com/search?q=hard-realtime+soft-realtime https://www.google.

That depends on whether we're talking about hard-realtime or soft-realtime. [0] https://www.google.com/search?q=hard-realtime+soft-realtime https://www.google.com/search?q=hard-realtime+soft-realtime > A hard-real time system is a system in which a failure to meet even a single deadline may lead to complete or appalling system failure. A soft real-time system is a system in which one or more failures to meet the deadline are not considered complete system failure, but that performance is considered to be degraded.

skyde 4y ago
even in the case of soft-realtime we don't say the system is real-time because it's fast. We say its realtime because majority of the time it meet its deadline.
- karmakaze 4y ago
  Yes, at the same time I don't know if I'd characterize a soft-realtime system as slow. One way to meet deadlines is by being very efficient/fast, while keeping variance low (e.g. no stop the world gc).
  - netr0ute 4y ago
    By that definition, a phone call that always takes 10 seconds for one side to hear the other is realtime.
    - AlotOfReading 4y ago
      That would indeed be a realtime system by common definitions as long as that latency is guaranteed. Audio and video are commonly considered soft-realtime domains for exactly that reason.
    - unsafecast 4y ago
      Yep. If you mean low-latency, say that. Real-time is an unfortunate name, but it means what it means.
    - numpad0 4y ago
      And phone … callthatju arousmpnnd is n’t realtime. Technically not relevant but I know that a lot of early handhelds that repurposed RTOS for GUI felt slow, jumpy and unresponsive, perhaps because everything was polled? In that sense RTOS can be slow.
      - unsafecast 4y ago
        I think it felt that way because of bad design + slow hardware. You see the exact same thing by installing a modern windows version or some desktop like GNOME to low-end computers.
- jcelerier 4y ago
  Who's that "we" ? For anyone I've worked with, real-time also implied "reaction time is faster than human perception"

skyde 4y ago

even in the case of soft-realtime we don't say the system is real-time because it's fast. We say its realtime because majority of the time it meet its deadline.

karmakaze 4y ago
Yes, at the same time I don't know if I'd characterize a soft-realtime system as slow. One way to meet deadlines is by being very efficient/fast, while keeping variance low (e.g. no stop the world gc).
- netr0ute 4y ago
  By that definition, a phone call that always takes 10 seconds for one side to hear the other is realtime.
  - AlotOfReading 4y ago
    That would indeed be a realtime system by common definitions as long as that latency is guaranteed. Audio and video are commonly considered soft-realtime domains for exactly that reason.
  - unsafecast 4y ago
    Yep. If you mean low-latency, say that. Real-time is an unfortunate name, but it means what it means.
  - numpad0 4y ago
    And phone … callthatju arousmpnnd is n’t realtime. Technically not relevant but I know that a lot of early handhelds that repurposed RTOS for GUI felt slow, jumpy and unresponsive, perhaps because everything was polled? In that sense RTOS can be slow.
    - unsafecast 4y ago
      I think it felt that way because of bad design + slow hardware. You see the exact same thing by installing a modern windows version or some desktop like GNOME to low-end computers.
jcelerier 4y ago
Who's that "we" ? For anyone I've worked with, real-time also implied "reaction time is faster than human perception"