Feb 232000

Installing FreeBSD via PLIP – (the parallel port – good for laptops)

This article was submitted by Cliff Rowley dozprompt@onsea.com.  It was good of him to write it up.  Thanks.

Cliff’s article

Just recently I was given an old Compaq LTE5280 notebook.  Almost immediately I decided that I *must* install FreeBSD on it, and set about the (now very familiar) task of installation.  I removed the floppy drive from the multibay, inserted the CD drive, and put in my FreeBSD 3.1 setup CD, and rebooted.  To my horror, the machine ignored the CD and continued to boot into the operating system already installed.  I quickly rebooted again, and scoured around the (somewhat limited) BIOS to find the boot options. It didnt happen.

Being so used to "plain sailing" installations, I had no idea how I was going to grace my new toy with my OS of choice, so I raced to http://www.FreeBSD.org to gather information on alterative methods.  I tried an installation from a DOS partition, which the notebook refused to play along to.  I have no network card (yet), so an FTP installation was out of the question.  This only left one other option – PLIP.

For those that are unaware of what PLIP is, or what it does, PLIP is a rather clever way of utilising a parallel port as a pseudo ethernet interface.  I must admit, the whole process looked rather daunting from the outset, but it was actually rather simple. For this reason, I’ve decided to submit this article to the FreeBSD Diary [Editor’s note: with my thanks].

A year or so ago (before I built up my LAN), I invested in a null modem (aka laplink) cable to share files between my home PC, and the machine I often borrowed from work.   If you are to follow the instructions in this article, you will need one yourself.   If you do not have one, or you cannot buy one, they are relatively simple to make yourself, but the schematics are beyond the scope of this article.  A quick visit to a search engine should do you some justice.

In order for this installation to work, you must also have another machine running FreeBSD (there are a few other operating systems that provide a compatible PLIP system, Linux being one of them – but dont forget to read ‘man plip’ first, since Linux uses a slightly different method).  Adding PLIP to your kernel is as easy as adding the line:

device plip0 at ppbus?

to your kernel configuration, recompiling your kernel, installing it and rebooting.   If you do not already have parallel support in your kernel, then you must add it.

Please be aware, that PLIP has a greater priority than other parallel activity, and other devices that exist on your parallel port will not work while the PLIP interface is up.

After your kernel is prepared, you will need to set up the interface on the machine that is to provide it’s gateway – that is, the machine with FreeBSD already installed on it.  You will notice (with a quick ifconfig -a) that you have a new interface – lp0. Because lp0 is just like any interface, you may set it up in a very similar way (with only one major difference).  Let’s start by giving it an IP address:

ifconfig lp0 inet netmask 0xffffff00

Notice the extra argument at the end of this statement. PLIP needs to know what the IP address at the other side of the link is (will be). Note that if you would like lp0 to be configured permanently, you may add it to rc.conf in exactly the same way as other interfaces, with one small change. Here is an extract from my rc.conf to illustrate:

interfaces="lo0 xl0 lp0"
ifconfig_xl0="inet netmask 0xffff0000"
ifconfig_lp0="inet netmask 0xffffff00"

Notice again the extra argument specifying the IP address at the other side of the link.

Once you have one side of the link set up, it is time (after plugging in the cable) to start the process of installation.  This article assumes that you already know how to perform an FTP install [Ed. note: Installing FreeBSD to replace Windows actually does an FTP install, so that might help], as there is only one more step to take that is different from a normal process.

Slap in your boot disk, select your options, and get yourself up to the point of choosing your installation method.  Choose FTP install, and you should be prompted to set up your network interface. Choose lp0, and enter the appropriate details, entering the IP address for *this* end of the link (in my scenario, this is   The only difference now from a normal FTP install, is that in the box entitled "Extra options to ifconfig", you must enter the IP address of the machine at the other end of the link – in this case,

As long as your lp0 interface has access to the outside world, there is nothing more to do, except grab a coffee and relish in the fact that yet another box is about to bathe in the glory that is FreeBSD.


  3 Responses to “Installing FreeBSD via PLIP – (the parallel port – good for laptops)”

  1. Hmm, just went looking for anything on the Compaq LTE 5280 laptop and FreeBSD, because I have one which I’m playing with, and a wireless net PCMCIA card which won’t speak Win95 (plus, I’m a Mac/Unix guy). D-Link DWL650 – working on the network with the wi0 driver (which is found whan I just slapped it into express mode without clearing conflicts – not a choice when visually fiddling with the kernel?).

    Anyway, it works on the net – with the fixit disk I can telnet out. All should be lovely, but the hard disk is MIA when I go to configure it, so I was wondering if anyone who had been though the process on this particular model had tips on that problem (previously, I had luck on a desktop model though this point, but had an ethernet card that was not FreeBSD compatible. I’m an old hand at sys admin in general, but still trying to get that first FreeBSD machine all the way up).

  2. I bought a parallel laplink cable today, found your article tonight, and now I have freeBSD running on a 486 that I found on the street in San Francisco.