Re: File output and buffering

[Maciej Sobczak <see.my.homepage@gmail.com>]

On 22 Sie, 15:22, "Dmitry A. Kazakov" <mail...@dmitry-kazakov.de>
wrote:

> It seems that you didn't read my posts.

I've read them, but did not understand.

> One last try. In your example, when
> characters of a message are sent *synchronously* (assuming E-mail as the
> transport layer, no back doors, etc) then each single character has to be
> sent as a reply to the answer to the earlier mail.

Then we have a different notion of "synchronously".
When I write something to the file, the operation is synchronous when
the program *waits* for the transfer to complete.

> The very ability to send
> multiple characters in one mail means that they are sent in parallel =
> asynchronously.

Then we have a different notion of "asynchronously".
When I write something to the file, the operation is asynchronous when
the program can continue while the transfer is being handled.

And we have also a different notion of "parallel".
When I send a mail, it is transferred serially over a network cable.
The longer is the mail the longer it takes (hint: with parallel
communication the time of transmission would not depend on the number
of characters in the mail, since they would be sent, well, in
parallel).

> Compare it to parallel vs. serial communication.

Nothing to compare.

> For the
> rest see
>
>    http://en.wikipedia.org/wiki/Buffer_%28telecommunication%29

Short, but nice. Especially point d).

> Note the category of the article, read the purposes of buffering.

Yes, the purpose d) is what I'm talking about. I use buffers to group
data into smaller number of bigger units. This is where the
performance gain comes from.

> Because it debunks your claim that the transfer of individual items is
> synchronous. It is asynchronous, when makes sense.

No, it is synchronous, since the program has to wait until the
transfer completes (if the transfer is triggered at all - the buffer
makes that happen less frequently).

--
Maciej Sobczak * www.msobczak.com * www.inspirel.com

Database Access Library for Ada: www.inspirel.com/soci-ada