Re: Nobody proposing new uk newsgroups - why ?

On Wed, 21 Dec 2005 12:16:16 +0000, Dave J
<requiem@xxxxxxxxxx> wrote:

> In MsgID<slrndqi66f.dsj.chris@xxxxxxxxxxxxxxxxxx> within
> uk.net.news.config, 'Chris Croughton' wrote:
>
>>> I pictured TCP machines as having like a 'filter box' (maybe I thought
>>> that's what a router was) that separated out the different port requests
>>> and fed them down separate pieces of wire to the computer. Don't forget,
>>> my *only* idea of a port was a physical serial or parallel port..
>>
>>Yup. And as far as users and most network application programmers are
>>concerned they might as well be exactly that. I use that mental
>>'picture' about ports, and pipes, and other communications channels.
>>Most people, including programmers, don't need to know anything about
>>the actual protocols, a 'picture' of it as actual holes (in a firewall,
>>for instance -- I hear admins talking about "poking a hole to let
>>$application through"), pipes and bits of wire is as good as any.
>
> Well, that's the whole point of the layered architecture, sort of like
> object orientation, you can picture the 'inside of the box' in any way you
> like. It makes no difference to the application opening a TCP connection
> if it's set up by a set of layered programs or whether the request is
> relayed to a bunch of switchboard operators who plug wires in accordingly,
> it still works the same.

And it can even /be/ switchboard operators -- or pigeon handlers, see
RFC 1175 -- and it doesn't matter apart from how long it takes. Every
layer is replacable (including by a 'null' layer).

> Most of the time there is no call to visualise how the job is getting
> done, it's just my personal preference when visualising the 'inside of the
> box' to see it in something that vaguely correlates with actual events.

Yup. But when I'm writing socket-based software I just think of it as a
'pipe' which connects thwo things via some 'magic'.

>>for instance -- I hear admins talking about "poking a hole to let
>>$application through"), pipes and bits of wire is as good as any.
>
> Oh, I thought it was a message sent to the switchboard to ask them to
> begin relaying calls that asked for extension nnnn..

Could be that as well.

> I especially liked the trick of getting them to relay calls for extension
> AAAA to extension QQQQ as you can have one well staffed office pretending
> to be a building full.

Heh. I like that analogy. If you don't already write manuals for
people who don't know about firewalls, may I suggest that you do so? I
can think of a number of 'hardware' routers which could benefit from
that sort of description...

Chris C
.

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