Nicholas Bodley wrote:

>On Tue, 19 Apr 2005 15:31:51 -0400, Richard Wordingham
><richard.wordingham@...> wrote:
>
>
>
>>'Email program' is too imprecise for some - it could refer to either the
>>client program (which is serving the human client) or the server
>>programs trying to dispatch, receive and screen e-mails.
>>
>>
>
>Indeed. While I don't know of specific instances, it's more than likely
>that a few computer users have set up a home machine as an e-mail server,
>or to include such a function.
>
>

A particular machine may serve as both a client and a server machine,
depending on its software configuration.

In my mind, the status as "client" or "server" is strictly a software
one. Using the terms to refer to a box (hardware) is merely a
convenience, but subject to misinterpretation depending on the context.
that is why I agree with Richard's comment above.

>I've seen some strong hints that the definitions of client and server seem
>backwards -- reversed -- in the X Window System, which is widely used for
>Unix and derivatives (loosely speaking), including Linux.
>
>
>

Can you explain a bit more? I don't know all the down and dirty details
of the XWindow protocol or implmentation (all of which is available
thanks to open surce licenses, btw, unlike the display subsystems of a
certain other populat operating system whose name begins with "W").

I have heard it is far more configurable and flexible then it is
generally set up for. But I have never noticed any confusion about which
part of the software is a server and which is a client. I would be
interested to know where your confusion arises from - maybe you are onto
something abut the literature, The few times I looked at XWindows
configuration docs, they did seem pretty dense and uncomprehensible to
me, compaared to the merely routinely dense and incomprehensible
configuration docs I deal with pretty commonly/

BTW, just to muddy the waters a bit more, sometimes servers request
services of other servers. Mail servers do that routinely as the forward
mail messages along. They may query many types of servers, includng
other mail servers, db servers, authentication servers, dns servers,
spam identification servers, blacklist servers, and who knows what else?

So, a server could act as a client momentarily to request services from
another server. Probably what makes it a server overall, is if it
primarily responds to querues from other clients according to a
particular protocol.

And that doesn't even address into P2P - where the server/client issue
is a lot more fuzzy by design.

Best,

Barry



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