nathanm@hp-pcd.UUCP (05/14/84)
This is not a request for a deep discussion of Physics or Philosophy. Just a point of curiosity for me: Is it ever possible for the net to violate causality? That is, is there any possible scenario in which a reply can get somewhere (presumably as an orphaned response) before its base note does? Personally, I can't envision such a scenario, but then I didn't know until reading net.sport.baseball last weekend that it IS possible to have more than three outs in an inning. Any ideas? Nathan Meyers hp-pcd!nathanm
dave@utcsrgv.UUCP (Dave Sherman) (05/22/84)
Articles reach places before previous articles all the time.
Here's a typical scenario:
foo+---+bar+---+baz+------+
| |
biff+---+boff+---bleff
Joe posts an article on Monday on machine "foo" asking for birthdays of
famous wombats. It gets to "bar" on Monday morning. The "bar"-"baz" link is
set up for midnight calls only, but "biff" gets it right away. "biff"'s
main news feed is to/from "bar", but "biff" sends locally-generated articles
to "boff" as well. "boff" therefore gets a followup from Fred on "biff" before
the original article makes it through baz->bleff->boff.
I know there are other reasons. Suggestions?
Dave Sherman
--
dave at Toronto (CSnet)
{allegra,cornell,decvax,ihnp4,linus,utzoo}!utcsrgv!davestanwyck@ihuxr.UUCP (Don Stanwyck) (05/23/84)
Not only is it possible, it is common. I frequently read a response, wonder at what basenote I haven't seen that would cause such a response, snd then just one or two notes later see the original. -- ________ ( ) Don Stanwyck @( o o )@ 312-979-3062 ( || ) Cornet-367-3062 ( \__/ ) ihnp4!ihuxr!stanwyck (______) Bell Labs @ Naperville, IL
barmar@mit-eddie.UUCP (Barry Margolin) (05/24/84)
I understand why it is possible to see followups before the originals. What I don't understand is why I sometimes see serial postings from the same person in the wrong order. For instance, the recent flames about censorship by unc!tim: the headers said which part they were, and they were displayed to me out of sequential order. -- Barry Margolin ARPA: barmar@MIT-Multics UUCP: ..!genrad!mit-eddie!barmar
chuqui@nsc.UUCP (Chuq Von Rospach) (05/25/84)
The reason a set of linked articles seem to always be out of order (as in
the Tim Maroney stuff) is because of the way uucp handles things in its
directories. If all the sites were running under batching software there
would be no problem because the batching stuff forces a FIFO setup on news.
Unfortunately, many sites still pass news on a message at a time. Uucp does
not understand FIFO. I don't know exactly what the execution algorithm is
for uux but it has much more to do with the position of the file in the
directory structure and the state of the moon than it does when uux got it
in relation to when uux saw it. In a busy directory creating and zapping
lock files and temp files and things it is very likely that a second
article can actually have its control file placed higher up in the
directory structure than the first one so that when uux starts scanning the
directory it is sent first.
chuq
--
From the closet of anxieties of: Chuq Von Rospach
{amd70,fortune,hplabs,ihnp4}!nsc!chuqui (408) 733-2600 x242
I'm really gonna miss her. A tomato ate my sister...henry@utzoo.UUCP (Henry Spencer) (05/27/84)
Uucp is not guaranteed to process incoming traffic in arrival order,
nor is it guaranteed to send outgoing traffic in queueing order. This
is a further factor tending to randomize the order of things posted
at about the same time.
--
Henry Spencer @ U of Toronto Zoology
{allegra,ihnp4,linus,decvax}!utzoo!henrytrt@rti-sel.UUCP (05/30/84)
As far as I know the uucp distributed with 4.2 BSD is FIFO within each priority 'grade', so with all 4.2 (or honey danber) sites news remains ordered even using the terribly inefficent method of one uux per article. Most uuxqt versions process files in an mysterious order and a single such site can mess up the ordering of news articles. I am not aware of a uucp that ships shortest-file first. By the way, there were some botches in the 4.2 queue ordering: 1) mail wasn't processed before news, resulting in large mail delays. 2) uuxqt got constipated if the 20 highest-priority incoming 'X.' requests could not be done due to missing files, resulting in emmense backlogs (ugh). Tom Truscott