0ef41a6718
boot(8) claims that boot will launch /$objtype/init; that is incorrect. It launches /$cputype/init (so says both boot.c and cpurc(8)). That's the more sensible choice. This patch fixes the man page to resolve the mismatch.
307 lines
5.9 KiB
Text
307 lines
5.9 KiB
Text
.TH BOOT 8
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.SH NAME
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boot, bootrc \- connect to the root file server
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.SH SYNOPSIS
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.B /boot/boot
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[
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.B -fkm
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]
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[
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.BI -u username
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]
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[
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.IB method ! fs-addr
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]
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[
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.I args
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]
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.SH DESCRIPTION
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.I Boot
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is the first program run after a kernel has been loaded. It
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mounts
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.B bootfs.paq,
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a compressed filesystem contained in
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.IR root (3),
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sets up the
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.IR rc (1)
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environment and executes
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.I /boot/bootrc
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passing on its arguments.
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.I Bootrc
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connects to the file server that will serve the root, performs any
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authentication needed to connect to that server, and executes the
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.IR init (8)
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program. Both
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.I boot
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and
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.I bootrc
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are started by the kernel, never run directly by the user.
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See
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.IR booting (8)
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for information about the process of loading the kernel (and
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.IR boot )
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into memory.
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.PP
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Once loaded, the kernel initializes its data structures and devices.
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It sets the two environment variables
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.B /env/cputype
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and
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.B /env/terminal
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to describe the processor.
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It then binds a place-holder file server,
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.IR root (3),
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onto
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.B /
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and crafts an initial process whose sole function is to
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.IR exec (2)
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.BR /boot/boot ,
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a binary which is compiled into
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.IR root (3).
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.PP
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The command line passed depends
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on the information passed from boot ROM
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to kernel.
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Machines that boot directly from ROM (that is, most machines other than PCs)
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pass the boot line given to the ROM directly to
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.IR boot .
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.PP
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On the PC, each line in the file
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.IR plan9.ini (8)
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of the form
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.IB name = value
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is passed to the boot program as an environment
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variable with the same name and value.
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The command line is
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.IP
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.B /boot/boot
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.IB method ! server
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.PP
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After
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.I boot
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passed its execution to
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.I bootrc,
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it must determine the file
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.I server
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to use
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and a
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.I method
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with which to connect to it.
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Typically this will name a file server on the network,
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or state that the root file system is on local disk and name the partition.
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The complete list of methods is given below.
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.PP
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.I Bootrc
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must also set a user name to be used
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as the owner of devices and all console
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processes and an encryption key to be used
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when challenged.
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.I Bootrc
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will prompt for these.
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.PP
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Method and address are prompted for first.
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The prompt lists all valid methods, with the default in brackets, for example:
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.IP
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.EX
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bootargs is (tcp, local!device) [local!/dev/sdC0/fscache]
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.EE
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.PP
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A newline picks the default. Entering
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.B !rc
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breaks into the
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.IR rc (1)
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shell.
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Other possible responses are
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.I method
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or
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.IB method ! address\f1.
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.PP
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The other interactions depend on whether the system
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is a
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terminal or a CPU server.
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.SS Terminal
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A terminal must have a
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.I username
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set.
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If not specified with the
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.B user=
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.IR plan9.ini (8)
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parameter or the
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.B -u
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option,
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.I boot
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will prompt for one on the console:
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.IP
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.EX
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user:
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.EE
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.PP
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The user will also be prompted for a password to
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be used as an encryption key on each
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.IR attach (5):
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.IP
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.EX
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password:
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.EE
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.PP
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Once connected,
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.I boot
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mounts
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the root file system before
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.B /
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and makes the connection available as
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.B #s/boot
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for subsequent processes to
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.B mount
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(see
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.IR bind (2)).
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.I Boot
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completes by
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.IR exec (2)'ing
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.B /$cputype/init
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.BR -t .
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If the
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.B -m
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option is given it is also passed as an option to
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.IR init .
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If the environment variable
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.B init
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is set (via
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.IR plan9.ini (8)),
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it is used as an argument to
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.IR exec (2)
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instead.
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.PP
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If the
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.I bootfs.paq
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has been built with the cache file system,
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.IR cfs (4),
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the local disk partition
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.BI /dev/sd XX /cache
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(where
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.B XX
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is a unit specifier)
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exists, and the root file system is from a remote server,
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then
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.I bootrc
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will insert a user level cache
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process between the remote server and the local namespace
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that caches all remote accesses on the local partition.
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The
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.B -f
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flag commands
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.IR cfs (4)
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to reformat the cache partition.
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.SS CPU Servers
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The user owning devices and console processes on CPU servers
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and that user's domain and encryption key are
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read from NVRAM on all machines except PCs.
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PCs keep the information in the disk partition
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.BI /dev/sd XX /nvram.
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If a
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.B -k
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option is given or if no stored information is found
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.I boot
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will prompt for all three items and store them.
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.IP
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.EX
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password:
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authid: bootes
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authdom: research.bell-labs.com
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.EE
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.PP
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The key is used for mutual authentication of the server and its clients.
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The domain and id identify the owner of the key.
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.PP
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Once connected,
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.I boot
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behaves as on the terminal except for
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.IR exec (2)'ing
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.B /$cputype/init
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.BR -c .
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.SS Booting Methods
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The methods available to any system depend on what was
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compiled into the kernel.
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The complete list of booting methods are listed below.
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.TP 8
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.BR tcp
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connect via Ethernet using the TCP protocol.
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The
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.I args
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are passed to
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.IR ipconfig (8)
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when configuring the IP stack.
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The
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.IR plan9.ini (8)
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variables
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.B fs
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and
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.BR auth
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override the file server and authentication server IP addresses
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obtained (if any) from DHCP during
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.IR ipconfig (8).
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.TP 8
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.B local
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connect to the local file system.
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The first argument is a disk holding a file system.
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.I Boot
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inspects the disk.
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.I Boot
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will configure the IP stack by passing
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.IR args ,
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if any, to
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.IR ipconfig (8).
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.RE
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.PP
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For the
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.B tcp
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method,
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the address must be a numeric IP address.
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If no address is specified,
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a file server address will be found from another
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system on the network using the BOOTP protocol and
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the Plan 9 vendor-specific fields.
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.SH EXAMPLES
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On PCs, the default arguments to boot are constructed using
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the
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.B bootargs
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variable in
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.IR plan9.ini (8).
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.PP
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Start
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.IR cwfs (4)
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in config mode:
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.IP
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.EX
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bootargs=local!/dev/sdC0/fscache -c
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.EE
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.LP
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Use an IP stack on an alternate ethernet interface
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with a static address and fixed file server and authentication
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server addresses.
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.IP
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.EX
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fs=192.168.0.2
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auth=192.168.0.3
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bootargs=tcp!-g 192.168.0.1 ether /net/ether1 \e
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192.168.0.50 255.255.255.0
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.EE
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.LP
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(The
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.B bootargs
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line is split only for presentation; it is one line in the file.)
|
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.SH FILES
|
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.B #s/boot
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.br
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.B #//boot/boot
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.br
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.B #//boot/bootfs.paq
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.SH SOURCE
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.B /sys/src/9/boot
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.SH "SEE ALSO"
|
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.IR root (3),
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.IR dhcpd (8),
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.IR init (8)
|
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.SH BUGS
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The use of
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.B bootargs
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in general is odd.
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