SUMMARY: Too Many Users

From: Trevor McFarland (
Date: Thu Nov 16 1995 - 05:18:17 CST

*** Attached File #1: NewPost ***
The error messages "Too many users on system, try again later" are caused by
a license limit imposed with Ultrix license. Details of this follow.

A "NI" value under ps -alx of "-10" is that of a high priority process.


My original post was:

>> I have two questions for my audience today.
>> (1) How do I set the number of logins allowed. Right now this seems to
>> be at 3, so any users after this are treated with "Too many users on the
>> system, Please try again later." This has caused some problems because many users
>> are using PC-Xware to come in via an xdm session, and PC-Xware is such garbage
>> that it often fails to exit cleanly, thus leaving the user's session open, and
>> tying up one of the three available logins.
>> I have also encountered a problem where the terminal's console menubar was lost,
>> leaving me no options to exit my session or bring up any xterms.
>> How can I increase the number of available sessions?
>> (2) On a smaller note, when doing a "ps -alx" on Ultrix 4.3A, when a "-10" value
>> is shown for NICE, is this a high priority or a low one.


Thanks for the responses from:

Kalle Flodkvist ("")
Jeff Prichard ("")
Andrea Zuccollo ("")
Andrej Misik ("")
Sean Watson ("")
Steve Simmons ("")
"Gary L. Jarrell" ("")
Kevin Lentin ("")
Norman Wilson ("")
Peter Young ("")
"" ("")


From: Kalle Flodkvist ("")

1)Probably a license limit. Do # lmf list
On my machine:
# lmf list
Product Status Users: Total Active

ULTRIX active unlimited

I have an unlimited ULTRIX license. You have a 2-user license, I guess.

2) -10 is a high priority.

Kalle Flodkvist
Box 174 Email:
751 04 UPPSALA Fax: +46 18 51 66 00
Sweden Telephone: +46 18 18 78 63

From: Jeff Prichard ("")

You need to purchase a "license upgrade" from Digital.

Jeff Prichard
Home: (414) 273-1798 Work: (414) 964-1658
                          It's Not my fault!

From: Andrea Zuccollo ("")

You should check you license database; see 'lmf' and related man pages
Bye from italy,


 Andrea Zuccollo is currently sitting at the Polytechnics of Milan
 Como site, located in via Castelnovo 7, 22100 Como, Italy.
 You can reach him by phone (+39 31 298 221), fax (+39 31 302 172) and
 e-mail (


From: Andrej Misik ("")

Max number of users who can log in simultaneously is determined by your Ultrix User License. To allow more users at the same time, you must purchase additional license (e.g. 8 user). See also section 'M4' in Ultrix FAQ.

Nice value is not the priority of the process, that's why you have columns named 'PRI' and 'NI' in the output of "ps -l". But one of the factors which determines priority of the process is its nice value.

However, the lower the nice value is, the higher priority the process should have. Negative nice value means very high priority. See also nice(1), nice(3), renice(8).

-- miso

------------------------------------------------------------------------------ Andrej Misik Dept. of Computer Science Email: Faculty of Mathematics and Physics Phone: (+42 7) 726 635 Comenius University Fax : (+42 7) 727 041 Mlynska dolina PGP public key available via finger: 842 15 Bratislava, Slovakia ------------------------------------------------------------------------------

From: Sean Watson ("")

Buy more licences (or if you have bought them, install them with lmf). Ultrix comes with a 2 user licence (I don't know how you manage 3), you can buy a PAK for more users (up to an unlimited licence).

It is hard to define a "user" in a Unix sense. (This is because users can run things in the background, have multiple windows/terminals in use, etc.) DEC had decided that there can only be "n" (n=2 in your case) login sessions. When a user logs in (via the "login" program), it decrements a counter somewhere. I don't know what other programs (DEC supplied XDM or dxsession apparently seems to) decrement this counter or by what means it is reincremented (maybe when the process that decremented it dies?). I've heard of schemes to circumvent the licencing by replacing login (and whatever else does that accounting) but this has bad consequences if (1) your're honest and/or (2) you use C2 security and don't want to edit in "authenticate_user()" to the user authentication checking routines. There may be good reasons to replace login, but avoiding paying the extra licenses is probably not one of them.

Processes that are "less nice" (have a low nice value) will cut into the run queue in front of processes that are "more nice" (have a high nice value). The way it was explained to me that a process will only run if there all processes with a lower nice value are waiting for I/O (or sleeping or whatever). If this is true (I'm not certain it is), -10 is equivilant to -1 if there are no other processes with a negative nice value.



From: Steve Simmons ("")

This is a licencse restriction -- you need to buy an upgrade from DEC.


From: "Gary L. Jarrell" ("")

Increasing the # of logins- Check the number of Utrix Licenses you have = by doing a lmf list. This will show you the number of users that are = authorized to login to you server/workstation at one time. The default = is two.

Gary Jarrell


From: Kevin Lentin ("")

I thought this was a licensing problem. I'm not sure about the answer to this one, but...

Negative nice values are higher priority. Positive is lower. Any process which runs for a long time often gets reniced to 4 automatically. Only root can reduce nice values below 0.

[=======================================================================] [ Kevin Lentin | The Mighty Carlton Blues | ] [ | 1995 AFL Premiers | ] [ Macintrash: 'Just say NO!' |CARLTON 21-15-141 d geelong 11-14-80| ] [=======================================================================]


From: Norman Wilson ("")

(1) If the system says `Too many users on the system', it means you've exceeded your license limits. The base Ultrix OS license allows only two simultaneous users (perhaps four on `server'-class machines); if you want more than that, you're supposed to buy a license upgrade from Digital. When you buy an upgrade, you'll get a piece of paper with a license key (a PAK), to be registered with lmf; once you've done that, more users will be allowed, up to whatever limit you've now paid for.

Few vendors have limited-user licenses these days on UNIX systems; I believe it has to do with an old version of the royalty agreement with AT&T for UNIX resellers, which had a smaller royalty for smaller systems. Digital's marketing folks wanted systems shipped with the smallest possible license, so they'd have the smallest possible cost, perhaps on the theory that most systems were used by just one user on a desktop anyway.

Legally speaking, you're cheating on your license, and therefore your legal agreement with Digital, even by letting more people in with xdm; it just happens that xdm is missing the code to enforce license restrictions. It's unlikely that this will cause you to get a letter from Digital's legal department, but Digital would be perfectly within their rights to change xdm to do so in some future release.

(2) For both scheduling priority (`PRI' in ps) and nice (`NI'), which is really just a fudge factor added to the priority, processes with numerically smaller values are run first. Hence if ps shows a nice of -10, that process gets more of the system than other processes.

Norman Wilson University of Toronto


From: Peter Young ("")

I believe the kernel sets a login limit. To change that limit, you must edit the config file and rebuild the kernel. I'm not sure however that this is your problem.

For example, here's a snippet from our /usr/sys/conf/mips/GENERIC file:

cpu "DSR4_5000_100" ident "GENERIC" timezone 5 dst maxusers 32 maxuprc 50 physmem 16

-10 is a very high priority. The normal range is between -20 and 20. Only superuser can set a priority below 0. Processes normally get started at 0, and have - priorities when operating in kernel mode (eg when doing I/O). When I say normal, I mean Unix not Ultrix. the ps man page might clear this up.


From: "" ("")

The real answer is: Buy a license upgrade from Digital. The maximum number of logins allowed is a function of the kind of license you have on the machine. You probably want an 8 user license, at least. That costs more money. By default, a workstation comes with a 2 user license (which I think actually allows three users, if one of them is "root").

The slimy answer is: Replace /usr/bin/login with a version that does not do license checking (you could probably just build and install the login program from 4.3BSD). You will then be able to have an arbitrary number of people logged in, though you'll be in violation of your license agreement with Digital.


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