Re: SLIP/PPP question (NOT the usual)

[nparker@cie-2.uoregon.edu (Neil Parker)]

In article <5i1v2t$h1s$5@news.vanderbilt.edu>
NOleshSPAMerjtHERE@vuse.vanderbilt.edu (Tilghman Lesher) writes:
>In article <334471DB.36B3@no.no>, Eric Jacobs (no@no.no) wrote:
>
>: It does seem like there should be a generic something program that can
>: communicate over any port, because most of the commands and responses are text
>: anyway.. but it doesn't seem like there is one.
>
>Oh, there definitely is one.  It's called UUCP for Unix to Unix CoPy, and it's
>the basis for ALL types of Internet connections.  Telnet, FTP, Gopher, and
>HTTP are all based upon UUCP.  If you have an older system, it's probably
>still available, just rarely used.  I don't think newer systems have UUCP
>as a separate program still included.

Sorry to disillusion you, but UUCP isn't by any stretch of the imagination
the basis of Internet connections.  UUCP is at heart just a file transfer
protocol, similar in concept to a fully-automated version of zmodem or
Kermit, with the added ability of each participating machine to store and
forward file transfer requests on behalf of other machines (this
store-and-forward capability is what makes the UUCP network posssible).

Some major differences between UUCP and TCP/IP:

UUCP is designed for use over modem connections, which are assumed to be
"expensive", so that connections are made only at certain times of the day
(for example, when long-distance rates are cheapest).  Transfer requests are
stored in the UUCP queue until the designated transfer time arrives, at
which time all the queued requests are transferred in one big batch.
TCP/IP is designed for use with connection hardware which is assumed to be
"cheap" and available immediately on demand 24 hours a day, 7 days a week.
There is no store-and-forward concept--if a connection cannot be made
immediately on demand, an error occurs.

UUCP makes only one connection at a time to one neighboring machine at a
time.  TCP/IP is a packet-switched protocol, allowing multiple connections
to exist with multiple different machines simultaneously.

UUCP is typically implemented as a group of user-level programs--the
standard way to issue *any* UUCP request is to invoke the "uucp" or "uux"
program with the appropriate command-line arguments.  TCP/IP is typically
implemented in the form of operating-system or library calls.

And those are just some of the major user-visible differences.  I'm not
even going to try to go into the low-level protocol differences.  Suffice
it to say that they're absolutely nothing like each other (being designed
to address entirely different problems).


There's no way you could possibly implement anything like telnet using
UUCP--UUCP's intrinsic store-and-forward philosophy is the exact
opposite of everything telnet is intended to be.  I suppose something like
HTTP or gopher would be possible, but in an environment where the file you
request today might arrive tomorrow, or next week, or next month (or never,
with no indication of the reason for the failure), why bother?

          - Neil Parker

(P.S.  Does anybody out there remember how this discussion was supposed to
be relevant to the Apple II?  I certainly don't.)
-- 
Neil Parker, nparker@{cie-2,cie}.uoregon.edu, http://cie-2.uoregon.edu/~nparker
                     "Bad move, Neil!"  -- The Tick

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