5 ms·

Introduction to Concurrency

66 points by gshrikant 11y ago

deleted 11y ago
[deleted]
taeric 11y ago
I was expecting something that would be a bit more controversial. I highly recommend reading through to the linked "neutral" analysis. Seeing evented and threaded styles as duals of each other is fairly useful. Especially if you take that to realize that ultimately you want to see the flow of the data. Oftentimes the specifics of implementation are more noisy than they need to be.
degenerate 11y ago
The page just sort of... ends. There is no conclusion, link to further reading, or anything useful at the end :\
- rtoal 11y ago
  Great observation. Fixed.
  - aseal 11y ago
    Dr. Toal- as a former student (decade plus) made me smile to see your post up on HN. Hope all is well.
    - bhauer 11y ago
      Agreed. It's awesome to see some rtoal material on HN this morning!
toolslive 11y ago
I think concurrency has nothing to do with doing things "at the same time". Concurrency is about overlapped execution, and you can very well have concurrency without parallelism. It might be one of those terms in computer science that has multiple definitions.
- jerf 11y ago
  Sorry, which term do you think is precisely defined such that all language communities would agree with your definition without question? So far as I know, there are none.
  - toolslive 11y ago
    there are plenty: syntax,type, stack, message, ...
    - gliese1337 11y ago
      Oh dear. You might be right about "syntax", but definitely not "type". There're all kinds of arguments over what a "type" is; "stack" is probably safe; "message", eh, has different definitions in reference to different programming languages, but I think everybody knows that and won't be confused in the context of any particular language, so that probably counts. But definite;y not "type". That's a can of worms.
      - rtoal 11y ago
        For those interested in debates about the word "type" here is just one out of a million online discussions that have taken place: https://github.com/JuliaLang/julia/issues/6113 https://github.com/JuliaLang/julia/issues/6113 It started with an argument over what a "dependent type" was. That said, type-as-interface and class-as-implementation gets some traction because it is just vague enough. Re parallelism and concurrency, a similar vague-enough distinction would be: parallelism is the state of things happening at once, while concurrency is the coordination and management of parallel activities? But I agree that a lot of people don't really make the distinction, and use the terms interchangeably, which is something Rob Pike pointed out (in the context of Go, here: http://blog.golang.org/concurrency-is-not-parallelism http://blog.golang.org/concurrency-is-not-parallelism)
        ihnorton 11y ago
        This article by Tomas Petricek goes into some interesting historical background and philosophical questions regarding types: http://tomasp.net/blog/2015/against-types/ http://tomasp.net/blog/2015/against-types/
gamdev 11y ago
This is down? Any chance for a reupload?
- rtoal 11y ago
  Power outage. It is back up.

66 points by gshrikant 11y ago

deleted 11y ago

[deleted]

I was expecting something that would be a bit more controversial. I highly recommend reading through to the linked "neutral" analysis. Seeing evented and threaded styles as duals of each other is fairly useful. Especially if you take that to realize that ultimately you want to see the flow of the data. Oftentimes the specifics of implementation are more noisy than they need to be.

degenerate 11y ago

The page just sort of... ends. There is no conclusion, link to further reading, or anything useful at the end :\

rtoal 11y ago
Great observation. Fixed.
- aseal 11y ago
  Dr. Toal- as a former student (decade plus) made me smile to see your post up on HN. Hope all is well.
  - bhauer 11y ago
    Agreed. It's awesome to see some rtoal material on HN this morning!

toolslive 11y ago

I think concurrency has nothing to do with doing things "at the same time". Concurrency is about overlapped execution, and you can very well have concurrency without parallelism. It might be one of those terms in computer science that has multiple definitions.

jerf 11y ago
Sorry, which term do you think is precisely defined such that all language communities would agree with your definition without question? So far as I know, there are none.
- toolslive 11y ago
  there are plenty: syntax,type, stack, message, ...
  - gliese1337 11y ago
    Oh dear. You might be right about "syntax", but definitely not "type". There're all kinds of arguments over what a "type" is; "stack" is probably safe; "message", eh, has different definitions in reference to different programming languages, but I think everybody knows that and won't be confused in the context of any particular language, so that probably counts. But definite;y not "type". That's a can of worms.
    - rtoal 11y ago
      For those interested in debates about the word "type" here is just one out of a million online discussions that have taken place: https://github.com/JuliaLang/julia/issues/6113 https://github.com/JuliaLang/julia/issues/6113 It started with an argument over what a "dependent type" was. That said, type-as-interface and class-as-implementation gets some traction because it is just vague enough. Re parallelism and concurrency, a similar vague-enough distinction would be: parallelism is the state of things happening at once, while concurrency is the coordination and management of parallel activities? But I agree that a lot of people don't really make the distinction, and use the terms interchangeably, which is something Rob Pike pointed out (in the context of Go, here: http://blog.golang.org/concurrency-is-not-parallelism http://blog.golang.org/concurrency-is-not-parallelism)
      - ihnorton 11y ago
        This article by Tomas Petricek goes into some interesting historical background and philosophical questions regarding types: http://tomasp.net/blog/2015/against-types/ http://tomasp.net/blog/2015/against-types/

gamdev 11y ago

This is down? Any chance for a reupload?

rtoal 11y ago
Power outage. It is back up.