Introduction (JavaStation- and sparc64-specific), Diskless NetBSD HOW-TO

Sun Firmware procedures

Which Sun machines can netboot

All JavaStation and sparc64 workstations and servers are capable of booting over a network interface. A network boot-strap procedure can be started by entering the appropriate OpenFirmware command. Some JavaStation-1 systems do not have OpenFirmware and should follow the OpenBoot sparc Diskless NetBSD HOW-TO.

Determining your ethernet hardware address

When you power on your machine, it will print out its MAC address. If it claims your ethernet address is ff:ff:ff:ff:ff:ff, then your NVRAM battery is dead. See the Sun NVRAM/Hostid FAQ. Your system will not netboot without a working NVRAM.

Obtaining an IP address via RARP

When instructed to boot "over the net", your workstation will first try to acquire an IP address by using the Reverse ARP (or RARP) protocol. Thus you need to run a RARP server somewhere in the same network broadcast domain as your workstation. The ethernet address of the machine (needed when setting up the RARP server) should be displayed in the banner when it is powered on or reset.

Sometimes the arp entry gets corrupt on the rarpd server. If this happens, you may need to run (on the rarpd server):

# arp -s client.test.net CC:CC:CC:CC:CC:CC temp

Note: if the client doesn't detect a rarpd server, it will patiently wait for one and will not display any error messages (as described in the rarpd pages).

Downloading the boot loader

If the RARP phase is completed successfully, the firmware in the workstation expects to be able to download a program via the TFTP protocol. It will do this by setting up a TFTP connection to the server that answered the earlier RARP request, and asking for a file named based on the machine's IP address.

Naming the boot loader

The netbooting machine will ask via tftp for a file named as follows:

The first eight characters are obtained by converting the four octets of the IP address into hexadecimal representation.

You can use bc(1) to calculate this name as follows:

$ bc
obase=16
192
C0
168
A8
1
1
10
A
quit

Thus, a machine which has been assigned IP address 192.168.1.10, will make an TFTP request for `C0A8010A'.

For sparc64 systems, this file should be a symbolic link to installation/netboot/ofwboot.net from the NetBSD/sparc64 distribution. For OpenFirmware-based JavaStation systems, this file should be a link to installation/netboot/bootjs.net from the NetBSD/sparc distribution. Of course this bootloader should be located in a place where the TFTP daemon can find it (remember, many TFTP daemons run in a chroot'ed environment).

Firmware commands

Open Firmware uses a generalized syntax to specify the boot device for use with the `boot' command. By default, the JavaStations will attempt to boot from the net automatically.

`boot net'; this will most likely work in all cases where there is a single network interface on the machine. In this case `net' will have been setup by the firmware as an alias to the full pathname of the network device.
You may want to specify a different kernel name or options. These are listed after the device name:
`boot net netbsd-GENERIC_SUN4U.gz -a'
You may also need to be explicit about the network device you want to use, e.g. because there's more than one interface in the machine, possibly connected to different subnets. In this case, use the full device path name in the boot command, for instance:
`boot /pci@1f,4000/network@1,1';
would select the on-board hme interface located on an Ultra 30.

Begin setting things up (suggested order):

Get installation/netboot/ofwboot.net (sparc64) or installation/netboot/bootjs.net from the NetBSD distribution. This is what is sent by TFTP. Copy this file to an appropriately named file in /tftpboot, as described above in the Naming the boot loader section.

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