boot(8) - NetBSD Manual Pages

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BOOT(8)             NetBSD/sgimips System Manager's Manual             BOOT(8)


NAME

     boot -- sgimips system bootstrapping procedures


DESCRIPTION

     Silicon Graphics MIPS-based computers all feature essentially similar
     firmware systems.  However, as of the Indigo R4x00 series (IP20), quasi-
     ARCS (Advanced RISC Computing Specification) compatible features are also
     present.  All known PROM implementations support loading executables from
     disk devices, as well as from the network via BOOTP and TFTP.

Disk Booting
     SGI provides a small filesystem at the beginning of each bootable disk
     called a Volume Header, which contains a boot loader and other standalone
     utilities.  Booting NetBSD requires that we write our bootloader into to
     the volume header using sgivol(8).

     Once a bootloader is present in the volume header, it may be executed
     directly by the PROM either manually, or at boot time using the
     ``OSLoader'' PROM environment variable.  The NetBSD bootloader will
     obtain the kernel filename to boot from the PROM or EEPROM.  This is
     specified by setting the PROM environment variable ``OSLoadFilename'' to
     an appropriate value.  For instance, ``/netbsd.ecoff''.

     For example, the following will configure the PROM to use the bootloader
     ``aoutboot'' to load the kernel ``netbsd.old''

           setenv OSLoader aoutboot
           setenv OSLoadFilename netbsd.old

Network Booting
     The system firmware will obtain an IP address, TFTP server address, and
     an optional filename from the BOOTP server and download it via TFTP.  The
     PROM's configurable network address environment variable ``netaddr'' must
     match the address provided by the BOOTP server.

     An example BOOTP entry for dhcpd(8) follows:

                host indigo3k {
                     hardware ethernet 08:00:69:42:42:42;
                     fixed-address 192.168.0.2;
                     option host-name "indigo3k.foo";
                     #filename "/netbsd.ecoff";
                     next-server 192.168.0.1;
                     option root-path "/export/indigo3k/root";
                     server-name "192.168.0.1";
                }

     To boot a kernel named ``netbsd.ecoff'' the user would type:
           boot -f bootp():/netbsd.ecoff

     See dhcpd.conf(5) for more information on configuring as a BOOTP server.


SEE ALSO

     dhcpd.conf(5), dhcpd(8), sgivol(8)


CAVEATS

     Some older PROM revisions do not support loading of ELF images.  The
     build system automatically prepares ECOFF versions, which are correctly
     interpreted.


BUGS

     NetBSD does not support booting from disk on systems lacking an ARCS-com-
     patible firmware (presently supported systems include Personal Iris and
     Indigo R3000).  It is possible to work around this by creating a suffi-
     ciently large volume header and placing the kernel in it, or by network
     booting.

     Some firmware revisions have a bug, which precludes them from communicat-
     ing with TFTP servers using ports above 32767.  When using NetBSD as the
     TFTP server, this problem may be worked around as follows:

           sysctl -w net.inet.ip.anonportmin=20000
           sysctl -w net.inet.ip.anonportmax=32767

     Another bug exists in some firmware revisions, which precludes the PROM
     from communicating with TFTP servers that employ PMTU (Path MTU) discov-
     ery.  This bug may be worked around by disabling PMTU on the TFTP server.
     This does not presently affect NetBSD servers.

     This man page is horribly incomplete.

NetBSD 5.0                      August 11, 2007                     NetBSD 5.0