On Apr 4, 2010, at 12:02 42PM, Larry Sheldon wrote:
> On 4/4/2010 09:57, Jorge Amodio wrote:
>>> UUCP is not a descriptor of any kind of a network in any engineering
>>> sense that I know of. It is a point-to-point communications protocol.
>>
>> You should revise some of the history behind it. It was a descriptor
>> for a very large network, it was even a TLD in the mid eighties when
>> the transition to DNS was taking place, the old bang style addresses
>> like mine original seismo!atina!pete transitioned for a while to
>> [email protected] and later to [email protected].
>
> I agree with some of this and most of the following, but I think the
> problem is not so much my history as it is the drift in definitions.
>
> And I do not pretend to any special authority in the area.
>
> But when I think of "network" I think of things like the PSTN, ABC,
> Mutual, California's DOJ torn-tape TTY, and FIDO where the message to be
> delivered was the focus and the internal works were pretty much
> uninteresting to the "user".
>
>> UUCP was not just a point to point protocol. Originally it was a set
>> of utility programs to permit copying files between Unix systems (Unix
>> to Unix CoPy, hence the name), since electronic emails where
>> essentially files UUCP became the transport mechanism for both
>> electronic email and later Usenet News.
>
> CoPy is the only decode that ever occurs to me. And the file view of
> the world is correct and I had forgotten it.
>>
>> Some referred to UUCP as Unix to Unix Communications Protocol, not
>> quite right but yes one of the pieces of UUCP (uucico = Unix to Unix
>> Copy in Copy Out) implemented different type of communication
>> protocols negotiated during the initial handshake phase and fine
>> tuned to different communication facilities, point to point, telephone
>> modems, specific modems such as Telebit Trailblazers with PEP,
>> different types of encapsulation using X.28, X25, and obviously
>> TCP/IP.
>>
>> For several years until we've got a more decent telecommunications
>> infrastructure UUCP was all we had in Argentina to let the academic
>> and science community reach out and communicate with their colleagues
>> around the world, we had an adapted version of the UUCP implementation
>> for DOS (some called it UUPC) that became very popular and enabled our
>> "UUCP network" to reach over 800 nodes in the early 90's when we later
>> were able to get a direct (IP) connection to the rest of the world.
>>
>> My .02
>
> Mine is that while "UUCP" took on a networkish patina in recent years (I
> know a place here in town that still uses it, or did when I last had
> contact with them a few years ago).
>
> But in it origins, UUCP was no more a network function that "cp" is
> today. (Hmmm....interesting digression. Was there NFS before there was
> IP? Seems like it, but I don't remember how it worked.)
>
> With UUCP you had to dial somebody up, say howdy (sometimes human to
> human) and issue the copy command. Sure enough, frequent users had cron
> jobs and scripts to do all that. And sure enough, co-operative sites
> would strip their own names off the beginning of a bang path and pass
> the file to the next in line, the next time they talked to them. Which
> might be anywhere from a few seconds to never from now.
There were two primary user-issued commands, uucp and uux (remote execution).
You'd say something like
uucp file... site!file
uucp site!file... file
uux site!command [site!file...]
uux command site!file...
The paths you could write to or retrieve from, as well as the list of commands
that could be executed remotely, were set in a configuration file. The former
was typically restricted much as anon-ftp is; the latter was typically rmail
and -- after about 1982 -- rnews for Usenet. There was very little, if any,
manual dialing; you typically either had an autodialer or you were polled by
someone who did. Calling frequency and legal times of day for calling were
also configurable, though polling -- and only polling -- was typically done via
cron. The receiving site did not strip its name off the email path, the
sending site did. That is, if I typed
mail foo!bar!bletch!user
my mailer would translate that to
uux foo!rmail bar!bletch!user
Site foo, in turn, would execute
uux bar!rmail bletch!user
etc. File transfer wasn't multihop, nor was remote execution per se. Usenet
used a flooding algorithm with duplicate suppression.
Uucp was designed for autodial modems, originally controlled by Bell
autodialers; on PDP-11s, you needed a DN-11 to control the dialer. The dialer
was hooked to a modem -- a real one, with no telephone or dial attached to it;
the modem was also hooked to a serial path. Even very early on, though, uucp
operated over higher-speed devices, such as the Bell Labs Datakit Virtual
Circuit Switch and the ARPANET.
Figuring the explicit mail routing path was annoying. I wrote (and Peter
Honeyman rewrote) a command called pathalias; it took topology and cost data
and generated the optimum path. Since cost had to reflect monetary cost,
reliability, and policy -- not everyone would forward for everyone else --
people had to tweak the metric to get the effect they desired. (That, at
least, should sound vaguely on-topic for NANOG...) But the visibility of the
path was the only thing ordinary users had to worry about.
--Steve Bellovin, http://www.cs.columbia.edu/~smb
