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Plan 9 - man page for boot (plan9 section 8)

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BOOT(8) 										  BOOT(8)

       boot - connect to the root file server

       /boot [ -fkm ] [ -uusername ] [ method!fs-addr ]

       Boot  is  the  first  program run after a kernel has been loaded.  It connects to the file
       server that will serve the root, performs any authentication needed  to	connect  to  that
       server,	and  exec(2)'s	the  init(8)  program.	 It  is  started by the kernel, never run
       directly by the user.  See booting(8) for information about the	process  of  loading  the
       kernel (and boot) into memory.

       Once  loaded,  the  kernel  initializes	its data structures and devices.  It sets the two
       environment variables /env/cputype and /env/terminal to describe the processor.	 It  then
       binds a place-holder file server, root(3), onto / and crafts an initial process whose sole
       function is to exec(2) /boot, a binary which is compiled into root(3).

       The command line passed depends on the information passed from boot ROM to kernel.  On the
       MIPS Magnum and SGI Power Series the command line passed to boot is the same as that given
       to the ROM monitor.

       On AT&T Gnots the command line is

	      /68020/9gnot method!server

       On the Nextstation , no information is passed from the boot ROM or program.   The  command
       line is


       On  the	PC,  each  line in the DOS file plan9.ini of the form name=value is passed to the
       boot program as an environment variable with the same name and value.  The command line is

	      /386/9pc method!server

       Boot must determine the file server to use and a method with which to connect to  it.   It
       must also set a user name to be used as the owner of devices and all console processes and
       an encryption key to be used when challenged.  Boot will prompt for these.

       Method and address are prompted for first.  The prompt lists all valid methods,	with  the
       default in brackets.

	      root is from (il, tcp, hs, local)[il]:

       A  newline  picks the default.  Other possible responses are method or method!address.  To
       aid in automatic reboot, the default is automatically taken on CPU servers if  nothing  is
       typed within 15 seconds.

       The other interactions depend on whether the system is a terminal or a CPU server.

       The  terminal  must have a username to set.  If none is specified with the -u option, boot
       will prompt for one on the console:


       The user will also be prompted for a password to be used as  an	encryption  key  on  each


       With  most methods boot can now connect to the file server.  However, with the serial line
       methods 9600 and 19200, the actual mechanics of setting up the complete connection are too
       varied  to  put	into the boot program.	Instead boot lets the user set up the connection.
       It prints a prompt on the console and then simulates a dumb terminal between the user  and
       the serial line:

	      Connect to file system now, type ctrl-d when done.
	      (Use the view or down arrow key to send a break)

       The  user can now type at a modem or a Datakit destination please: interface to set up the
       connection to a TSM8 card.  At Murray Hill, a user  would  type	nj/astro/plan85  at  this
       point.	When  the user types a control-D, boot stops simulating a terminal and starts the
       file system protocol over the serial line.

       Once connected, boot mounts the root file system before / and makes the connection  avail-
       able  as  #s/boot  for  subsequent  processes  to  mount (see bind(2)).	Boot completes by
       exec(2)'ing /$objtype/init -t.  If the -m option is given it is also passed as  an  option
       to init.

       If  the kernel has been built with the cache file system, cfs(4), the local disk partition
       /dev/[sh]d[01]cache exists, and the root file system is from a  remote  server,	then  the
       kernel  will  insert  a	user  level cache process between the remote server and the local
       namespace that caches all remote accesses on the local partition.  The  -f  flag  commands
       cfs to reformat the cache partition.

   CPU Servers
       The  user  owning  devices and console processes on CPU servers and that user's domain and
       encryption key are read from NVRAM on all machines except PC's.	PC's keep the information
       in the disk partition /dev/[sh]d[01]nvram.  If a -k option is given or if no stored infor-
       mation is found boot will prompt for all three items and store them.

	      authid: bootes
	      authdom: research.att.com

       The key is used for mutual authentication of the server and its clients.  The  domain  and
       id identify the owner of the key.

       Once connected, boot behaves as on the terminal except for exec(2)'ing /$objtype/init -c.

   Booting Methods
       The methods available to any system depend on what was compiled into the kernel.  The com-
       plete list of booting methods are listed below.

       cyc     connect via a point-to-point fiber link using Cyclone boards.  If  specified,  the
	       address must be the number of the Cyclone board to be used, default 0.

       il      connect via Ethernet using the IL protocol.

       tcp     connect via Ethernet using the TCP protocol.  This method is used only if the ini-
	       tial file server is on a Unix system.

       hs      connect via Datakit using the high speed Datakit card.

       incon   connect via Datakit using the Incon interface.

       9600    connect via Datakit using the serial interface at 9600 baud.

       19200   connect via Datakit using the serial interface at 19200 baud.

       local   connect to the local file system.

       For the il and tcp methods, the address must be a numeric IP address.  If  no  address  is
       specified,  a  file  server address will be found from another system on the network using
       the BOOTP protocol and the Plan 9 vendor-specific fields.  For the  Datakit  methods,  hs,
       9600,  19200, and incon, the address must be specified and must be a relative path name to
       the file server.  If no address is specified, the address Nfs is used.



       root(3), bootp(8), init(8)

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