Syslinux - Nov 2006 - run pxelinux.0 on a booted system

I am trying to come up with a 'clever' way to pxe-boot boxes that
don't have any
way to pxe boot.  as in, old laptops that only have pc-mica nics.

"Etherboot does not (yet) offer support for PCMCIA cards." 
http://www.etherboot.org/wiki/pcmcia_support

I am not trying to do 'that' - just trying to come up with a process to
work
around it.  Something like this:

Boot a Live CD.  (eventually one I customize with a nifty script to do all of 
this)  Now I have support for my pcmica nic.

Now do the part that PXE would do:

dhcpclint, get an IP, netmask etc.
and a file name (pxelinux.0) and maybe a server name.

use tftp client to get that file:
juser at v550b:~$ tftp shaz
tftp> get pxelinux.0

run it.

That should turn around and
ftp> get pxelinux.cfg/default

and give ma a boot:
which will let me select:

label ubuntu-edgy-alternate-hands-off
         kernel
ubuntu/edgy/alternate/install/netboot/ubuntu-installer/i386/linux
         append initrd=sc/e-a/initrd.gz ramdisk_size=16503 root=/dev/rd/0 rw 
locale=en_US console-setup/layoutcode=us netcfg/wireless_wep= 
netcfg/get_hostname= DEBCONF_DEBUG=5
preseed/url=http://shaz/preseed-edgy-alt.cfg --

And so this will happen

tftp> get ubuntu/edgy/alternate/install/netboot/ubuntu-installer/i386/linux
tftp> get sc/e-a/initrd.gz

and then this linux would be run from the local HD's fs (ramdisk fs really),
and
somehow it would load initrd.gz and get all those other parameters.

I am skipping the dhcp step for now, cuz that may be pointless if I can't
get
this to work:

juser at v550b:~$ chmod a+x pxelinux.0
juser at v550b:~$ ./pxelinux.0
-bash: ./pxelinux.0: cannot execute binary file
juser at v550b:~$ sudo ./pxelinux.0
./pxelinux.0: 1: Syntax error: "&" unexpected (expecting
")")

Ok, come to think of it, that won't work.  it isn't an elf binary with
the
needed headers and all.  guessing it wants the CPU in real mode.  hmm, don't
know what it is, so lets try some other stabs:

juser at v550b:~$ sudo grub
grub> root=(hd0,0)
grub> kernel /home/juser/pxelinux.0
Error 13: Invalid or unsupported executable format

and just in case you are wondering (like I was)

grub> chainloader /home/juser/pxelinux.0
Error 13: Invalid or unsupported executable format

grub> root=(hd0,0)
grub> kernel /home/juser/linux
grub> initrd /home/juser/initrd.gz
Error 16: Inconsistent filesystem structure

huh?

I am hoping that once I can get pxelinux.0 to run, the rest will just happen as 
if it had pxe booted over a supported nic.

I realize I am trying to step all over a running OS, and OS's normally
don't
like that.  So yes, I am braving new territory.

Carl K

Carl Karsten wrote:
> I am trying to come up with a 'clever' way to pxe-boot boxes that
don't have any
> way to pxe boot.  as in, old laptops that only have pc-mica nics.
> 
> "Etherboot does not (yet) offer support for PCMCIA cards." 
> http://www.etherboot.org/wiki/pcmcia_support
> 
> I am not trying to do 'that' - just trying to come up with a
process to work
> around it.  Something like this:
> 
> Boot a Live CD.  (eventually one I customize with a nifty script to do all
of
> this)  Now I have support for my pcmica nic.
> 
> Now do the part that PXE would do:
> 
> dhcpclint, get an IP, netmask etc.
> and a file name (pxelinux.0) and maybe a server name.
> 
> use tftp client to get that file:
> juser at v550b:~$ tftp shaz
> tftp> get pxelinux.0
> 
> run it.
I doubt this will work:

I am pretty sure pxelinux.0 wants to run in real mode.

Normally: the nic rom runs in real mode, it is the nic driver for pxelinux.0
I was thinking it was OK because I would never "return from pxelinux.0 to
the
OS" and so it wouldn't matter if I somehow flipped into real mode.
I don't "come back" from pxelinux.0, but it does call into the OS,
which ..
won't be anything it can call into anymore
I was relying on the OS's pcmica nic support to get around "no pcmcia
nic pxe"
but the OS is all protected mode and so this isn't going to work, right?