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From: kupfer@ucbvax.BERKELEY.EDU (Mike Kupfer)
Newsgroups: net.bugs.4bsd
Subject: Re: ruptime reports 0 users (it's *worse*)
Message-ID: <11232@ucbvax.BERKELEY.EDU>
Date: Sat, 14-Dec-85 02:36:14 EST
Article-I.D.: ucbvax.11232
Posted: Sat Dec 14 02:36:14 1985
Date-Received: Sun, 15-Dec-85 00:08:59 EST
References: <5444@allegra.UUCP> <629@pucc-j>
Reply-To: kupfer@ucbvax.UUCP (Mike Kupfer)
Organization: University of California at Berkeley
Lines: 33

>>ruptime may claim that a machine with lots of users on it has 0 users.
>>This is because it reads only the first 1K bytes of a whod file into a
>>buffer, and assumes that it can read an array of structures backwards
>>from the end of the buffer.  What it gets, if the whod file is big enough,
>>is a bunch of garbled structures.

I thought about this a bit as part of my M.S. project.  I don't see the
wisdom in broadcasting multi-KB packets to all the machines on your
net, just so that everyone knows that you have 44 (rather than 41)
users.  My idea of fixing the problem is to include a flag in the
packet that says "there's more than would fit in this packet" and then
having ruptime note that the flag was set.

This implies that for heavily loaded systems rwho will leave off some
names, but I don't see that as a major hassle as long as it's not done
silently.  After all, rwho information is nice, but not especially
critical (I think), and if you have lots of users, your cycles and
network bandwidth have better things to do than tell who's logged on
across the net.

Comments, anyone?

mike
-----
Mike Kupfer
Xerox ISD (formerly at U.C. Berkeley)
kupfer.pa@xerox.ARPA
...!ucbvax!kupfer (gets forwarded)
-- 
Mike Kupfer
Xerox ISD
kupfer.pa@xerox.ARPA
...!ucbvax!kupfer (gets forwarded)