Re: aws vs ruby rails or php? how much faster?

["Yannick Duchêne (Hibou57)" <yannick_duchene@yahoo.fr>]

Le Tue, 23 Apr 2013 12:08:15 +0200, Dmitry A. Kazakov  
<mailbox@dmitry-kazakov.de> a écrit:

> On Tue, 23 Apr 2013 09:10:39 +0200, Yannick Duchêne (Hibou57) wrote:
>
>> Asynchronous I/O can be achieved with Ada too, and that does not implies
>> tasking, just wrapping what the OS provides for that.
>
> Oh, it does. I don't know what you guys are talking about, but  
> asynchronous
> I/O is intimately related to tasking.

Yes it is, but as you said, it save tasks. The application doing  
asynchronous I/O, does not even need to run multiple tasks, just only one  
which is its own task, as the second may be required task can be provided  
by the OS (and may be just interrupts, depending on the kind of I/O). When  
I said “does not implies tasking”, I wanted to underline the same as you  
did, that it does not cost tasks.

> If you have tasks you normally don't need asynchronous I/O, you do it in  
> a
> blocking way.
>
> If you have one task or less tasks than I/O requests pending, you do I/O
> asynchronously.
>
> With many simultaneous requests you should go asynchronous because the
> number of tasks is limited. An OS can handle far less simultaneous tasks
> than simultaneous I/O requests/channels.
>
> For either HD or sockets you could do I/O synchronously (blocking) or
> asynchronously (non-blocking).
>


-- 
“Syntactic sugar causes cancer of the semi-colons.” [1]
“Structured Programming supports the law of the excluded muddle.” [1]
[1]: Epigrams on Programming — Alan J. — P. Yale University