README for Prisma boot server patches to ISODE 8.0

Contents:
  isod.c.diff		Patch to "support/isod.c" to add the boot server
			code.
  isoservices.diff	Adds the boot service to "etc/isoservices".
  ifconfig.ed0		Example ifconfig file to set the local NSAP
			on a NetBSD 1.3 system.
  esis.c.diff		Patch for "usr/src/sys/netiso/esis.c" in the
			NetBSD kernel (NetBSD-Amiga 1.3.2).
  README.Prisma		This file.


What are these patches for?
---------------------------
These patches implement a very crude boot server to support netbooting
of an ISICAD Prisma diskless workstation. These patches have only been
tested using ISODE 8.0 running on NetBSD 1.3 on an Amiga. There are likely
to be byte-ordering issues if run on a platform with different endianness
from the 680x0.

The boot server outputs progress messages so that I can see what is
happening. For this reason, the 'tsapd' daemon must be run as a
foreground task instead of as a true daemon. I usually run it from
a root shell as 'tsapd -z'.

Why is there a delay in the transfer loop?
------------------------------------------
The arbitary delay of 120ms works most of the time on my 50MHz 68060
powered Amiga. It is in there because I found that the Prisma likes
data to arrive 1024 bytes at a time in separate CLNP packets. If I
just send all the data to the OSI transport layer, the internal
buffering can output data in larger or smaller packets as it sees
fit. This breaks the Prisma's boot loader. I consider this a bug
in the Prisma but since I can't fix that end, I add the delay as
a crude work-round. You may need to increase it if running on a faster
machine.


Note on OSI networking support
------------------------------
ISODE can be built on systems with TCP/IP but without OSI networking,
it was designed to allow implementation of the upper layers of the OSI
stack on top of a TCP transport layer. For the Prisma boot server,
however, it MUST be built on a platform with real OSI networking support
in the kernel. A list of supported platforms is given in the ISODE
documentation but the only freely available ones that I know of are the
BSD derivatives.

Kernel patch for NetBSD 1.3.2 on the Amiga
------------------------------------------
I have not been able to get a Prisma to boot using ISODE running on
the standard kernel. There is an incompatibility somewhere in the ES-IS
route handling which I have been unable to track down (and I did spend
quite a bit of time trying). For now, I make a one line change to 
disable ES-IS handling, rebuild the kernel and all is well. If anyone
figures out what the real solution is, I would like to hear from
them!



George Harvey
fr30@dial.pipex.com
7th May 1999