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From: mckee@MITRE.ARPA.UUCP
Newsgroups: mod.protocols.tcp-ip
Subject: Peak User Estimate
Message-ID: <8704011439.AA23779@mitre.ARPA>
Date: Wed, 1-Apr-87 09:39:52 EST
Article-I.D.: mitre.8704011439.AA23779
Posted: Wed Apr  1 09:39:52 1987
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    Based on some envelope calculations, described below, I estimate
that the peak number of simultaneous users is 10% of the potential
users.  Is this estimate in accord with your experience?

    The system I use here at MITRE is a VAX 8600 running Ultrix.  I have
recently had occasion to be interested in the peak number of
simultaneous users as a percentage of the number of possible users.  
So, on 24 March, I copied the /usr/users file and found 551 entries,
some of which had not logged-in since 1985!  Recognizing that some user
accounts simply forward mail to another system, I deleted every entry
whose last login was 28 February, or earlier.  That left 191 users that
had logged-in at least once during the period 1-24 March.

    Over the past several months I have, at unplanned intervals, run the
Unix "who" command that lists all logged-in users.  The usual response
is 10 to 15 users; very rarely does the number equal or exceed 20.  The
estimate made above follows from this data.