	This distribution contains the files and information to boot plip
(typically on a laptop type of computer), and connect it to another linux
box.  This can make installation of Slackware a breeze, since you can NFS
mount an external disk via PLIP and have access to an entire CDROM.

	For those of you that do not know what PLIP is, it is Parallel
port IP - in a sense just TCP/IP over the parallel port.  Due to the
nature of the interface, you can only connect two computers together
at one time via PLIP, although machines with regular ethercards can
obviously do routing.  The throughput is not fast by ethernet
standards, but with many older laptops you simply do not have the ability
to connect a regular ethercard to the machine.  There do exist parallel port
ethernet adapters, which would probably be preferable, but PLIP is cheaper
and will be fine if you just want to get the network up long enough to install
linux on the laptop.  I have measured data throughputs of roughly 6Kb/sec,
which is better than you would get with SLIP (TCP/IP over serial port).

	Note:  The shell on the boot diskette is zsh, which works fine, but
some of the Slackware scripts do not like very much.  Thus the proper procedure
is probably to use the boot diskette to get things up, and then run bash
from the NFS machine.

Note:
	For the PLIP interface, I have arbitrarily chosen 18.0.0.1 for
the laptop machine, and 18.0.0.2 for the linux box you want to connect
to via PLIP.  The 18.*.*.* is actually a class A network IP-space reserved
by MIT, so people at MIT might have routing problems with this, but the idea
is that we add explicit routings for this one set if IP numbers, so there
should not be too many problems.   If someone who is IP-savvy knows of some
IP numbers that can always be safely used here, feel free to speak up.

If you use PLIP on a regular basis, you should get a locally assigned IP
number for the laptop.  Any local machines would also need to have routing
information so that packets get delivered to the machine to which you
are connecting the laptop.

Security concerns:
------------------

	If you install this, you will need to export parts of your
filesystem to the machine on the end of the PLIP interface.  This
leaves open big security holes, since someone else could easily come
up to your machine with a laptop and a PLIP boot diskette and mount
whatever filesystems you have exported.  Thus extreme caution should be used
when you configure this.  Note that if you shut down the PLIP interface
with 

	ifconfig plip1 down

when you are through with PLIP, that you have effectively closed the hole, but
you have to remember to do this whenever you are done.  Technically some sort
of PCNFS type of authentification should probably be used before mounts
are allowed via the PLIP interface.

Note: Technically some of the same security holes exist for normal ethernet - 
it is always considered a bad thing (for more or less any definition of
bad) to export your root filesystem, esp if you export it read-write.


Prerequisites:

	The linux machine to which you want to connect to via PLIP must already
be configured for TCP/IP.  There are no requirements about the laptop - the
idea is that you can do a new install on the laptop via PLIP.

Installation:

	On your main machine you will need to add a couple of lines to
the various network scripts.  You will start by adding the following
lines to your rc.net file (usually in /etc, but if you are running a
SysV type of init, it could be in a subdirectory rc.d).  For the
purposes if our example, consider your laptop to have

	ifconfig plip1 18.0.0.2 netmask 255.255.255.252 broadcast 18.0.0.3
	ifconfig plip1 up
	route add 18.0.0.1 plip1

Next, you need to edit your /etc/hosts file and add something like
(feel free to use the name of your linux machine and a more meaningful
domain name here - the important thing is the IP numbers, as these must
match what the laptop wants to come up with):

	18.0.0.1	lxlaptop lxlaptop.org  # laptop
	18.0.0.2	lxsrv lxsrv.org # machine

Finally you will need to edit /etc/exports and add a line like:

/cdrom     lxlaptop.org(r)	# allow mounting of cdrom via NFS.
/home/joe     lxlaptop.org(rw) # allow mounting of home directory via NFS.

so that the laptop will be able to NFS-mount portions of your filesystem.
Here I have added a line to export anything below /cdrom - in principle one
could export anything below "/", but this is a grave security risk.
You can export multiple directories, of course.

	You will need a PLIP cable.  The PLIP docs explain how to do
this, but it is often easier to simply go to CompUSA and buy a cable -
look for a "LapLink" type of cable.  They generally run about 8$ or so.

	Once you have this much set up, you need to make the plip boot
diskette itself.  Just put a blank formatted diskette in the 3.5" drive
and use the command (assuming the 3.5" drive is /dev/fd0 or the "A" drive).

	dd if=plip1440 of=/dev/fd0 bs=1024 count=1440

	Once you have done this, you just insert the PLIP boot
diskette into the laptop and boot from it.  This diskette has LILO
installed, so it will prompt you for which image to boot from (even
though there is only one image on the diskette).  After booting, it
will prompt you for the root diskette - just press return, since the
one diskette is a bootable root diskette.  This will boot linux on the
laptop and get things started.  You can then use the command:

	/sbin/mount /nfs

to mount the directory /cdrom on the remote system over the /nfs mount point.

Note: The PATH environment on the PLIP boot diskette is set up to include
/nfs/bin:/nfs/usr/bin:/nfs/usr/local/bin, so once you mount the cdrom,


	Please address questions and comments to Eric Youngdale at
eric@aib.com
