Meyer, OO and concurrency

David Hopwood <>
Thu Jul 14 21:12:55 CEST 2005


todd wrote:
> David Hopwood wrote:
>> todd wrote:
>>> Joe Armstrong (AL/EAB) wrote:
>>>
>>>> What does "If better involves low latency then Erlang is not better."
>>>> mean?
>>>>
>>>> I can think of a lot of definitions of latency - in some an Erlang
>>>> implementation will be faster than a C implementation, in others it 
>>>> will be the other way around.
>>>>
>>> If you think latency is in the language then I am confused. It's a 
>>> property of the OS when using OS services.
>>
>> No, it's a property of any software component when using the services
>> of that component. At the language level, the relevant questions are
>> "What obstacles does the language put in the way of writing components
>> with guaranteed low latency? Or with low expected latency?" Similar
>> questions also apply to language implementations.
> 
> I am blocking on an a semaphore which is an OS construct. Sombody 
> unblocks me through an OS sempahore call. That schedules my task to run, 
> in the OS. The OS runs my task. What's the language have to do with any 
> of that?

Nothing, *for this example*. But if the semaphore (or any other kind of
concurrency construct) were provided by a language, then the language would
have a lot to do with it.

-- 
David Hopwood <>




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