2-user systems

[Piercarlo Grandi]

On 26 Nov 90 11:30:40 GMT, dawes at suphys.physics.su.OZ.AU (David Dawes) said:
dawes> Nntp-Posting-Host: suphys.physics.su.oz.au

dawes> For what its worth: On DEC's Ultrix with a 2 user license, a max
dawes> of 2 users may be logged in at a time.  These 2 users may however
dawes> be logged in any number of times (from ethernet, serial lines,
dawes> console or wherever).  root is also able to login when two other
dawes> users are logged in.  This to me seems the most logical way of
dawes> implementing a 2-user system.

No, it's a famous and catastrophic bug of some old release of Ultrix.
It is catastrophic because the limit is not two logins, but two UIDs, as
you say; so it can be easily circumvented by using the same uid for
multiple users, and more nastily, if you have something like uucp or the
printer spooler or other daemon running under its own UID, the number od
UIDs is reduced even if nobody is logged in.
--
Piercarlo Grandi                   | ARPA: pcg%uk.ac.aber.cs at nsfnet-relay.ac.uk
Dept of CS, UCW Aberystwyth        | UUCP: ...!mcsun!ukc!aber-cs!pcg
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