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NDBOOTD(8) NetBSD System Manager's Manual NDBOOTD(8)
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ndbootd -- Sun Network Disk (ND) Protocol server
ndbootd [-s boot2] [-i interface] [-w windowsize] [-d] boot1
ndbootd is a server which supports the Sun Network Disk (ND) Protocol.
This protocol was designed by Sun before they designed NFS. ND simply
makes the raw blocks of a disk available to network clients. Contrast
this with the true namespace and file abstractions that NFS provides.
The only reason you're likely to encounter ND nowadays is if you have an
old Sun 2 machine, like the 2/120 or 2/50. The Sun 2 PROMs can only use
ND to boot over the network. (Later, the Sun 3 PROMs would use RARP and
TFTP to boot over the network.)
ndbootd is a very simple ND server that only supports client reads for
booting. It exports a disk that the clients consider to be /dev/ndp0 (ND
public unit zero). The disk is available only to clients that are listed
in /etc/ethers and have valid hostnames. (Sun 2 PROMs don't do RARP, but
they do learn their IP address from the first ND response they receive
from the server.)
boot1 is a file containing the mandatory first-stage network boot pro-
gram, typically /usr/mdec/bootyy. The layout of the exported disk is:
· block 0: normally a Sun disklabel (but ignored by the PROM)
· blocks 1-15: the first-stage network boot program
With the -s boot2 option, ndbootd will also make a second-stage network
boot program available to clients, typically /usr/mdec/netboot. When
boot2 is a filename, that file is the single second-stage network boot
program to be served to all clients.
When boot2 is a directory name, typically /tftpboot, ndbootd finds a
client's second-stage network boot program by turning its IP address into
a filename in that directory, in the same manner later Sun 3 PROMs do
when TFTPing (i.e., if a client has IP address 192.168.1.10, ndbootd
expects to find /tftpboot/C0A8010A.SUN2 ).
When used in this last manner with an ND-aware first-stage boot program,
ndbootd serves the same purpose in the Sun 2 netboot process as tftpd(8)
serves in the Sun 3 netboot process.
Any second-stage network boot program always begins at block 16 of the
exported disk, regardless of the length of the first-stage network boot
All first- and second-stage network boot programs must have all exe-
cutable headers stripped off; they must be raw binary programs.
The remaining options are:
Only listen for ND clients on interface interface. Normally
ndbootd listens for clients on the first non-loopback IP
interface that is up and running.
This adjusts the window size of the ND protocol. This is the
number of 1-kilobyte packets that can be transmitted before
waiting for an acknowledgement. Defaults to 6.
-d Run in debug mode. Debugging output goes to standard error
and the server will not fork.
Whether or not there is a second-stage network boot program, the exported
disk appears to all clients to have infinite length. The content of all
blocks not used by the first- or second-stage network boot programs is
undefined. All client reads of undefined blocks are silently allowed by
NetBSD 5.0 May 9, 2001 NetBSD 5.0