alan@nabeth.DEC.COM (Alan Rollow - Alan's Home for Wayward Tumbleweeds) (07/25/88)
In a recent posting, someone asked about the affect that the
MAXUSERS configuration had on the login limit. The answer
virtually none at all. It is used by Ultrix at boot time to
create various system tables to be large enough for that many
users. The original 4.2BSD rules for sizing those tables are on
pages 5-103, 5-104 and 5-105 in "Building 4.2BSD with Config" in
the System Manager Supplementary Documents. The rules may have
changed a little in the four versions of Ultrix that have come
out since then, but they are mostly the same.
In V1.X the login limited is hard coded in the object module
machdep.o. The only way to raise the limit was get a new
module, put it in the right place and build a new kernel.
Because machdep.o changed in every version it became a night-
mare trying to make sure customers with login limit upgrades
got the new version. Starting in V2.0 the code was changed to
use a file which kept the information about the login limit.
This file is /upgrade. The intent is that this will be usable
for all releases of V2. To make sure that your increased login
limit follows a new version of Ultrix you just keep a copy and
put in the right place after the new version has been installed.
To install a new user upgrade, you replace the old file with the
new one and reboot. You'll probably want to build a new kernel
to set MAXUSERS up so the system tables will be suitably sized,
you don't HAVE to.
The only way to raise the login limit of a V1.2 system is to get
the appropriate copy of machdep.o. You'll also need to be licensed
for it. That is because AT&T sells licenses based on login limit.
You're probably better off upgrading to V2.2.
Alan Rollow
Digital Equipment Corporation
Colorado Springs CO.