Subject: Re: How does a PC boot from floppy?
To: None <>
From: Simon Burge <>
List: port-i386
Date: 10/13/1999 07:56:19
"Steven Grunza" wrote:

> Hi,
>   I'm thinking of creating a boot floppy for some of the systems around
> here.  They are large memory (128+ MB) Pentium+ machines with Win95,
> Win98, and WinNT on them.  I'd like to run them diskless without a swap,
> thus avoiding any changes to their local drives.  To do this, I would
> need to boot from floppy with a floppy that handled:
> 1) Reverse ARP to determine IP address
> 2) TFTP to get kernel
> 3) The kernel would need to know how to do NFS mounts of all needed file
> systems.

The netboot stuff supports loading the kernel via NFS without having to
use TFTP.

> It seems that most of this code should already exist in some form or
> another.  Does any one have a suggestion as to where to find the
> documentation on how to do this?  I've checked the
> page.  The systems don't support BIOS netbooting.  More information on
> the program might be all I need.  Thanks for any and all who
> can help.

If your ethernet card is supported by the standalone stuff (look at the
Makefile in /usr/src/sys/arch/i386/stand/netboot), you should be able to
make a "" - I've got a DOS floppy, and all it's got on it is
"" and "autoexec.bat" with "netboot" in it.

In my bootptab on the server, I've got (this file is machine generated):

		:ds=dnsquery bindmaster:\



And under /dlboot0/simonpc.root I just extracted all the installation
sets and hand-configured a few things in /etc.

We've got a separate filesystem with all our diskless client's swap
files that dont get backup up - here's the relevent lines from the

	balrog:/dlswap    /swap   nfs     rw
	/swap/simonpc     none    swap    sw
	swap              /tmp    mfs     rw,-s=60000

There was a thread here back in April with the subject of "netbooting
from a floppy disk bootblock" that had some info on what I did.  All in
all this works well, and the PC support guys here at work don't know my
"NT only" peecee runs NetBSD 99% of the time :-)