. First and foremost, before beginning the installation process, .Em make sure you have a reliable backup of any data (e.g., an old IRIX installation) you wish to preserve.
p Booting .Nx*M for the first time is most commonly done from the network. You must set up DHCP, TFTP, and NFS for the installation procedure to be successful. Some SGI bootproms, such as the ones found on O2s, can read ELF kernels directly from the network, others require that you boot an ECOFF version of the kernel. You will notice this from the following message from PROM:
p .Dl Illegal f_magic number 0x7f45, expected MIPSELMAGIC or MIPSEBMAGIC.
p You can convert the standard ELF format kernel into an ECOFF kernel using the
a elf2ecoff tool.
p Different SGI hardware will require the executable code in the loadable image to start at a different address. You must decide which image your system is capable of loading. The current options are: .(bullet Indigo2, Indy, Challenge S t O2 .bullet)
p Additionally there may be a third type in the future for 64bit machines. From now on this document assumes you are familiar with selecting the correct image for your system.
p Note that some older bootproms have an interesting bug in reading the kernel via TFTP. They handle the port number as a signed entity, and can thus not connect to ports >32767. You can work around this problem on the TFTP server (given that it is a NetBSD host) by using .Dq sysctl to set .Dq net.inet.ip.anonportmin and .Dq net.inet.ip.anonportmax to more suitable values.
p The O2 internal MACE Ethernet chip isn't supported yet, so to boot the O2 and mount nfsroot, you will need an external NIC in the PCI slot.