Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!udel!mmdf
From: waltje%minixug.uucp@plains.nodak.edu (Fred van Kempen)
Newsgroups: comp.os.minix
Subject: Re: Why does everything say "limit of 3 users"?
Message-ID: <32572@nigel.ee.udel.edu>
Date: 5 Oct 90 16:07:49 GMT
Sender: mmdf@ee.udel.edu
Lines: 47

In article <1990Sep24.213213.26431@jarvis.csri.toronto.edu>, wayne@csri.toronto.edu (Wayne Hayes) wrote:
> Why does the Minix documentation still say "Limit of 3 users"?  Is there
> some code hidden somewhere that only allocates only 3 logons or something?
> What about Gordan's Virtual Consoles?  I have logged on as root, wayne,
> and 2 friends accounts at the same time *and* had someone over the modem
> *and* the second serial port hooked into my amiga accross the desk (I run
> Minix on the PC, not the Amiga -- yet.)  That's a grand total of 6
> simultaneous users with vanilla 1.5 + virtual console.
Plus the MUX driver I will soon post for the AST FourPort/XN and EightPort !
(so, I have cons[1..4], [tty[5..8] and mux[0..7] !

> 	If you have enough serial ports, where's the limit?
CPU performance and/or memory size !
I run with a FREECOM 286/16 with 16Mbyte ("minixug") and a NEAT 286/20
with 8Mbyte ("uwalt").  Both machines are _very_ fast, and run fine
as long as all users keep away from any compiler...

You may remember the _real_ problem in MINIX on high-speed machines,
which is the single-tasking FS server.  MINIX version 1.2 had an extension
from Larry Hubble which allowed for message queueing.  This really boosted
up the overall performance!

So, for many users, you must:

1.  Have a fast CPU (>= 16MHz 286 or 386)
2.  Have plenty of memory (>= 4Mb)
3.  Have a (some) fast and large disk(s) (>= 40Mb, <= 28ms)
4.  A lot of serial port boards (COM1: - COM4) and a MUX (AST FourPort)
5.  Have the Virtual Console stuff from Gordon Irlam installed
6.  Add Message Queueing and/or Multi-Threading to the operating system

Well, items 1-5 are fully supported by NLMUG Advanced MINIX; item 6 is
"yet to be done".  I think we should have another look at the message
queueing stuff from Larry, and implement it in 1.5 FS.
After that, we could start thinking about adding multiple threads per
process to the kernel (Andy? How did you do it in Amoeba?) ...

Comments, anyone?

Fred.
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