4 ms·

The emphasis being on "hard" real time. Does anyone know of Lisp in (hard) real time applications in current use?

by freilanzer 4y ago

Keyframe 4y ago
https://corecursive.com/lisp-in-space-with-ron-garret/ https://corecursive.com/lisp-in-space-with-ron-garret/
- freilanzer 4y ago
  Cool, but: "The year is 1988."
  - beanjuiceII 4y ago
    does that really change anything? other than ya people were doing this in lisp way back when
    - dunefox 4y ago
      The question was specifically about current usage.
rurban 4y ago
Lisps in Space are hard real time
- freilanzer 4y ago
  But AFAIK Lisp isn't in space anymore, at least actively, right? Wasn't even the remote control agent rewritten in C++?
  - omginternets 4y ago
    Surely that doesn't matter? Seems like they can be real-time, even if they are no longer? What am I missing?
    - freilanzer 4y ago
      You're missing that I asked for current projects in Lisp.
      - omginternets 4y ago
        That's completely irrelevant, though. - Claim: "it is possible to write hard-real-time lisp, as evidenced by people having done it in the past." - You: "nobody is doing it right now" That's not a counterpoint.
        deleted 4y ago
        [deleted]
        freilanzer 4y ago
        I have no idea what you are even talking about. I'm asking about current projects in Lisp for real time, so it's very relevant. You might need to work on your reading comprehension.
  - vindarel 4y ago
    It is, at least, in James Webb https://www.stsci.edu/contents/newsletters/2018-volume-35-issue-03/artificial-intelligence-techniques-used-in-the-spike-planning-and-scheduling-system https://www.stsci.edu/contents/newsletters/2018-volume-35-is... for the scheduling system.
    - p_l 4y ago
      Scheduling runs ground side as normal Unix app
- discreteevent 4y ago
  Is there any evidence for that? Robotics is not necessarily hard real time. Hard real time means that something must complete within a tight deadline every time it executes no matter what.
  - ducktective 4y ago
    >within a tight deadline Isn't hard real-time only about upper-bound of tasks? Like if every task could be proven to run under t seconds (not necessary small), it is eligible for being called hard real-time.
    - 0xcde4c3db 4y ago
      Formally, yes. Practically, once t is large enough, violations of the constraint are much more likely to involve "acts of god" (power outages, rogue backhoe operators, natural disasters, wars, etc.) even if conventional best-effort techniques are applied.
varjag 4y ago
For hard RT you need both the OS and the language runtime to maintain certain constraints, and I am not aware of Lisp implementations satisfying that. Nothing to be concerned about tho, it's a fairly small niche that is not addressed by most of the popular languages today too. (Doing soft-RT work in Common Lisp though)

The emphasis being on "hard" real time. Does anyone know of Lisp in (hard) real time applications in current use?

Keyframe 4y ago

https://corecursive.com/lisp-in-space-with-ron-garret/ https://corecursive.com/lisp-in-space-with-ron-garret/

freilanzer 4y ago
Cool, but: "The year is 1988."
- beanjuiceII 4y ago
  does that really change anything? other than ya people were doing this in lisp way back when
  - dunefox 4y ago
    The question was specifically about current usage.

rurban 4y ago

Lisps in Space are hard real time

freilanzer 4y ago
But AFAIK Lisp isn't in space anymore, at least actively, right? Wasn't even the remote control agent rewritten in C++?
- omginternets 4y ago
  Surely that doesn't matter? Seems like they can be real-time, even if they are no longer? What am I missing?
  - freilanzer 4y ago
    You're missing that I asked for current projects in Lisp.
    - omginternets 4y ago
      That's completely irrelevant, though. - Claim: "it is possible to write hard-real-time lisp, as evidenced by people having done it in the past." - You: "nobody is doing it right now" That's not a counterpoint.
      - deleted 4y ago
        [deleted]
      - freilanzer 4y ago
        I have no idea what you are even talking about. I'm asking about current projects in Lisp for real time, so it's very relevant. You might need to work on your reading comprehension.
- vindarel 4y ago
  It is, at least, in James Webb https://www.stsci.edu/contents/newsletters/2018-volume-35-issue-03/artificial-intelligence-techniques-used-in-the-spike-planning-and-scheduling-system https://www.stsci.edu/contents/newsletters/2018-volume-35-is... for the scheduling system.
  - p_l 4y ago
    Scheduling runs ground side as normal Unix app
discreteevent 4y ago
Is there any evidence for that? Robotics is not necessarily hard real time. Hard real time means that something must complete within a tight deadline every time it executes no matter what.
- ducktective 4y ago
  >within a tight deadline Isn't hard real-time only about upper-bound of tasks? Like if every task could be proven to run under t seconds (not necessary small), it is eligible for being called hard real-time.
  - 0xcde4c3db 4y ago
    Formally, yes. Practically, once t is large enough, violations of the constraint are much more likely to involve "acts of god" (power outages, rogue backhoe operators, natural disasters, wars, etc.) even if conventional best-effort techniques are applied.

varjag 4y ago

For hard RT you need both the OS and the language runtime to maintain certain constraints, and I am not aware of Lisp implementations satisfying that. Nothing to be concerned about tho, it's a fairly small niche that is not addressed by most of the popular languages today too. (Doing soft-RT work in Common Lisp though)