README

This is latd - a LAT terminal daemon for Linux and BSD. It provides the 
following features:

- Provides LAT login services (you can log onto Linux from a DECserver)
- Can have multiple login services with different service ratings
- Static and dynamic service ratings are supported
- Provides Reverse-LAT. "devices" in /dev/lat/ can be used to connect to
  advertised services on DECservers or VMS/Tru64 hosts
- Provides queueing facility for reverse LAT ports. Useful for printers
- Can provide a node responder service for small-memory DECservers
- Full featured latcp control program - most internal parameters can be
  changed on the fly
- A script is run at daemon startup to provide customisation
- man pages for all programs and config files
- Group codes can be used for to restrict incoming and outgoing sessions
- User-space daemon. No kernel patching or recompiling necessary
- Does not need DECnet support from the kernel or libraries
- Supports a group called "lat" to restrict users of reverse-LAT ports
- llogin program so users can log into LAT services
- moprc for remote management for terminal servers.
- To send BREAK to a remote server in a reverse-LAT session press ^@

For Linux you will need Packet Socket support in the kernel, but I think that's
usually the default anyway. BSD systems use the Berkeley Packet Filter. 
Although Linux also has a BPF, latd cannot use it.

This software will not work on Linux kernels 2.0 or lower.

You should start latd with the latcp -s command. Starting latd manually is not
supported and may result in unexpected behaviour. See the man page for latcp
for more information.

This code is a clean-room reverse-engineering effort. I have no access to
HP technical documentation or source code for LAT and nor do I want any.

This software should work on all architectures supported by the target
operating systems. I have tested it on Intel, Alpha, SPARC, MIPS, PA-RISC and
PowerPC.

SUPPORTED SYSTEMS
-----------------
LATD itself runs on Linux and several BSD systems: NetBSD, FreeBSD and Darwin
have been tested. Not all the ports are tested very thoroughly, as I primarily
use Linux and Darwin.

The following systems I know to work on the other end of LATD because I have 
tested them, others may also work.

OpenVMS 7.2 & 7.3 (VAX & Alpha)
DEC Unix v4.0d
DECserver 200/MC
DECserver 90M
DECserver 90L+
DECserver 700

COMPILING
---------
LAT uses GNU autoconf to configure and build so all you should need to
do is 

./configure && make

to compile, and

make install

to install

There are several things you can tweak in the configuration process:

--enable-debug   Build a debug binary that does not daemonise itself
                 and issues lots of loggin messages to stderr
--with-login     Sets the login program to use for incoming connections. This
                 defaults to the local login program (/bin/login or 
                 /usr/bin/login). If you want to disable logins you can either
                 use --with-login=/bin/false or add "$LATCP -D -a `uname -n`"
                 to latd.conf
--prefix         Sets where the binaries are installed 
                (default /usr/local)
--sysconfdir     Sets where the config file is kept 
                 (default is /usr/local again)
                 Note that if you set --prefix to /usr, you will probably
                 also want to set --sysconfdir to / so that the config 
                 file goes in /etc rather than /usr/etc

PRINTING
--------
You can use latd and Linux as a printer server. See latprint.sh for 
for more information.

CREDITS
-------
The BPF interface used in the *BSD ports was written by Matthew Fredette
(fredette@netbsd.org), as was much of the autoconf system.

I'd like to thank Eduardo Serrat for providing much help, trace logs
and encouragement in this reverse-engineering effort.

I am also very much indebted to Real Dupeux for sending me a DECserver 200
for the project, without which it would be much impoverished.

I would also like to express gratitude to ABB for providing a DECserver 90M and
to Rob Davies for DECserver 90L+s.