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From: cudcv@warwick.ac.uk (Rob McMahon)
Newsgroups: comp.unix.xenix,comp.unix.questions
Subject: Re: How many uids and gids are allowed in SCO Xenix?
Message-ID: <1990Jul3.152354.6357@warwick.ac.uk>
Date: 3 Jul 90 15:23:54 GMT
References: <1990Jun28.031638.15931@cunixf.cc.columbia.edu> <1990Jun28.165234.23491@DSI.COM>
Sender: news@warwick.ac.uk (Network news)
Organization: Computing Services, Warwick University, UK
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In article <1990Jun28.165234.23491@DSI.COM> syd@DSI.COM writes:
>SCO, like most Unix's uses 16 bits for the uid and gid.  Thus the upper limit
>is 16 bits.  However, when you start to network, you will find some bugs re
>negative uid's in many Unix's so the practical limit is 32767, not 65535 for
>the upper limit.

On the other hand there used to be bugs in assorted utilities with [ug]id's as
low as 2-3000.  I can't speak for SCO Unix, and we can't get the source these
days, so I can't see whether they've all been chased down in the systems that
did have these problems.

I've seen `lastcomm' dumping core, `ls' taking forever, and `ps' printing
numbers instead of usernames, because of static uid->username mapping tables
sized at compile-time and indexed by uid.  (lastcomm ignored the problem, I
think ls kept one entry cached outside 0-2000, and ps just punted.)  I'm sure
this was true in 4.1BSD and SunOS 2.0.

Rob
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Rob McMahon, Computing Services, Warwick University, Coventry CV4 7AL, England