NAME

boot − start UNIX or a standalone program

SYNOPSIS

> b [ device [ (c,u ,p) ] ] [ filename ] [ −a ] boot-flags
> b? 
> b! 

DESCRIPTION

The boot program is started by the PROM monitor and loads the UNIX kernel, or another executable program, into memory. 

The form b?  displays all boot devices and their device arguments. 

The form b!  boots, but does not perform a RESET. 

Booting Standalone

When booting standalone, the boot program (/boot) is brought in by the PROM from the file system.  This program contains drivers for all devices. 

Booting a Sun-3 Over the Network

When booting over the network, the Sun-3 PROM obtains a version of the boot program from a server using tftp(1). The client broadcasts a RARP request containing its Ethernet address.  A server responds with the client’s Internet address.  The client then sends a tftp request for its boot program to that server (or if that fails, it broadcasts the request).  The filename requested (unqualified — not a pathname) is the hexadecimal, uppercase representation of the client’s Internet address, for example:

Using IP Address192.9.1.17 = C0090111

When the Sun server receives the request, it looks in the directory /tftpboot for filename.  That file is typically a symbolic link to the client’s boot program, normally ndboot.sun3.pub0 in the same directory.  The files ndboot.sun3.pub1 and ndboot.sun3.private are also valid (there may be others).  These files can be used to boot by default from an alternate public, or from a private nd(8C) partition.  If you link to one of these other files, then the client will boot from the corresponding partition by default.

The server then transfers the file to the client.  When successfully read in by the client, the boot program will jump to the load-point, and load vmunix (or a standalone program).  If the program is not read in successfully, boot responds with a short diagnostic message. 

Booting a Sun-2 Over the Network

The Sun-2 boots from its nd server directly.  The "boot block" loads /pub/boot, which in turn loads and runs vmunix, the system kernel. 

UNIX Startup

Once it is loaded and running, the kernel performs some internal housekeeping, configuration of device drivers and allocation of internal tables and buffers.  It then starts process number 1 to run init(8), to perform file system housekeeping, start system daemons, initialize the system console, and begin multiuser operation. Some of these activities can be skipped if init(8) is invoked when certain boot-flags, entered as arguments to the boot command, are passed along to init(8) by the kernel.

OPTIONS

device is one of:

ieIntel Ethernet
ec3Com Ethernet
leLance Ethernet (Sun 3-50)
sdSCSI disk
stSCSI 1/4" tape
mtTape Master 9-track 1/2" tape
xtXylogics 1/2" tape
xyXylogics 440/450 disk

cis a controller number,0 if there only one controller for the indicated type of device. 

uis a unit number, 0 if only one driver.  (Over the network, the unit number is the host portion of the file server’s IP address). 

pdesignates a partition.  The value you supply is exclusive-or’d with that of the default partition (indicated by the selected boot program, see Booting a Sun-3 Over the Network, above). 

filename
is the name of a standalone program in the selected partition, such as stand/diagor vmunix. Note that filename is relative to the root of the selected device and partition.  It never begins with /.  If filename is not given, the boot program uses a default value (normally vmunix). This is stored in the “vmunix” variable in the boot executable file supplied by Sun, but can be patched to indicate another standalone program loaded using adb(1).

−a prompt interactively for the device and name of the file to boot. 

boot-flags
The boot program passes all boot-flags to the kernel or standalone program.  They are typically  arguments to that program or, as with those listed below, arguments to progams that it invokes. 

−b Pass the −b flag through the kernel to init(8) to skip execution of the rc.local script. 

−h Halt after loading UNIX. 

−s Pass the −s flag through the kernel to init(8) for single-user operation.

FILES

/boot the standalone boot program

/tftpboot/???????? a symbolic link to the boot program for a client

/tftpboot/ndboot.sun3.pub[01] programs to boot from a public nd partition

/tftpboot/ndboot.sun3.private program to boot from a private nd partition

/tftpboot/ndboot.sun2.∗ Sun-2 boot programs (currently unusable)

/usr/mdec/installboot script to install boot blocks from a remote host

SEE ALSO

init(8), kadb(8S), monitor(8s), rc(8), reboot(8)

System Administration for the Sun Workstation

Installing UNIX on the Sun Workstation

BUGS

On the Sun-2, the PROM passes in the default name “vmunix”, overriding the the boot program’s patchable default. 

Sun Release 3.2  —  Last change: 30 June 1986