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From: jbdp%computer-lab.cambridge.ac.uk@cs.ucl.ac.uk (Julian Pardoe)
Newsgroups: net.unix-wizards
Subject: Re:
Message-ID: <254@brl-smoke.ARPA>
Date: Thu, 24-Apr-86 08:44:33 EDT
Article-I.D.: brl-smok.254
Posted: Thu Apr 24 08:44:33 1986
Date-Received: Tue, 6-May-86 04:27:10 EDT
Sender: news@brl-smoke.ARPA
Lines: 61

> I  would  love  to  see  some  instructions  on kernel mods to improve
> rlogin/telnet performance. 4.4 is a ways off on the horizon...
>
> Alan Langerman

Something quite promising was posted on mod.sources recently.  I enclose
part of the README below.  If you can't get hold  of  the  posting  from
somewhere closer to hand I'll forward the whole thing to you.

Newsgroups: mod.sources
Subject: 4.2bsd rlogin enhancements
Date: 7 Apr 86 17:43:48 GMT
Article-I.D.: panda.1617
Posted: Mon Apr  7 18:43:48 1986
Sender: jpn@uucp.panda
Approved: jpn@panda.UUCP

Mod.sources:  Volume 4, Issue 52
Submitted by: genrad!decvax!philabs!nyit!rick

NYIT rlogin performance enhancements			01-Apr-86

INTRODUCTION
This package contains a set of source code modifications to
.2bsd UNIX to enhance the performance of rlogin connections.
Performance improvement results from reducing the involvement
of the agent processes (rlogin and rlogind) in the task of
passing characters between the client and server hosts.
In this implementation, the agent processes retain their
previous function of establishing an rlogin-style connection
between two hosts; however, once the connection is established,
the agents sleep until the connection is interrrupted by an
escape character on the client host, or terminated by either host.
The character-switching functions formerly performed by rlogin
and rlogind are now handled entirely within kernel interrupt
logic, eliminating the delays and scheduling overhead of the
original implementation and improving response and throughput.

It is important to note that, although the character traffic
is now being handled exclusively in the kernel, the rlogin
protocol has been maintained.  This ensures that an enhanced
client can interoperate with a vanilla 4.2bsd server, and
vice versa, still gaining an improvement in performance.

The implementation is separated into two logical parts:  client
and server.  The client part is called the NVT, an acronym for
Network Virtual Terminal; the server is called the NVS, meaning
Network Virtual Server.  Within the kernel, NVT logic appears
within a "#ifdef KNVT" conditional, and NVS logic appears
within a "#ifdef KNVS" conditional.  All user-mode NVT logic
resides in /usr/ucb/rlogin.  All user-mode NVS logic resides
in /etc/rlogind.

Julian Pardoe
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