BOOT(8) UNIX System V BOOT(8)
NAME
boot - from power on to the login prompt
DESCRIPTION
At power on the machine reads the first sector of the boot
device into memory and executes it. This bootstrap code
loads /boot, the Minix Boot Monitor. The monitor loads the
kernel binaries from /minix, or the newest file in /minix if
it is a directory.
The Minix system is now running, the different tasks
initialize themselves and control is transferred to the last
one, init.
Init is the grandparent of all Minix processes, it is
responsible for starting login processes on each terminal,
but first it runs /etc/rc.
/etc/rc checks the state of the system and starts daemons.
First it sets the keyboard translation to the mapping in
/etc/keymap if present, then it reads the time zone from
/etc/timeinfo followed by a call to readclock(8) to set
Minix time from the hardware clock. Next the file systems
are checked if necessary and the /usr file system is
mounted.
The system is now ready for multiuser startup, /etc/rc
starts the update(8) and cron(8) daemons, and initializes
the network services. /etc/rc finally recovers crashed
editor buffers and cleans out the tmp directories.
Init reads /etc/ttytab and starts a getty(8) for each
enabled terminal line to allow a user to log in.
BOOT ENVIRONMENT
Many features of the drivers inside the kernel are
controlled by settings in the boot environment. The values
of these variables are usually colon or comma separated
numbers configuring the driver. DPETH0 = 300:10 tells the
ethernet driver to use I/O address 0x300, interrupt request
10, and the default memory address (0xD0000, values may be
omitted) for the first ethernet board. (Note that IRQ 2 is
redirected to IRQ 9 on AT's and PS/2's, so use 9 if a device
is jumpered for 2.)
Variables that are special to both the monitor and the
kernel are described in monitor(8). This section lists
extra variables or variable settings:
hd = at | bios | esdi | xt
Choose the driver that is to be used for the hard disk,
in order: IBM/AT (classic AT or newer IDE), BIOS
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(generic driver), ESDI (some PS/2's), or IBM/XT. By
default the first of these drivers that is enabled is
used. Most drivers are present in the kernel as
distributed, but may be taken out by modifying
/usr/include/minix/config.h. (An XT should always use
the BIOS driver, not the XT driver, because BIOS calls
are cheap on an XT. The XT driver can be used on AT
machines with an old XT controller.)
DPETHn = on | off
Turn an ethernet board on or off. The driver is by
default in "sink" mode for all boards. The sink mode
allows one to use the driver without an ethernet board
installed. The driver will play /dev/null for that
device, i.e. nothing comes in, and anything send out is
dropped on the floor. If the board is turned on then
the driver will use it to send out packets, if it is
turned off then the driver will fail for that board.
DPETHn = I/O-addr:irq:mem_addr
Set the I/O address (hex), IRQ (decimal) and memory
address (hex) of the n-th ethernet board and turn it
on. By default they are configured as 280:3:D0000 and
300:5:CC000. The memory address is ignored for the
Novell ethernet boards, but may be explicitly set to
zero to indicate that the board is a Novell ethernet
board. You do not need to specify the IRQ with modern
Western Digital 8013 compatible ethernet cards, the
driver asks the board what its IRQ is. (Note that the
default IRQ conflicts with the second serial line, so
the serial line is turned off if the ethernet board is
configured for IRQ 3.)
DPETHn_EA = e0:e1:e2:e3:e4:e5
Set the ethernet address of the n-th ethernet board.
The address is normally obtained from the ethernet
board, so only in exceptional circumstances is this
setting ever needed. (Use the address of the main
server if you want a career change.)
AHA0 = I/O-addr:bus-on:bus-off:tr-speed
Configure the Adaptec 154xA SCSI host adapter to use
the given I/O address (hex), Bus-on time (decimal),
Bus-off time (decimal) and transfer speed (hex). The
default is 330:15:1:00. The default transfer speed is
always 5.0 Mb/s (code 00) ignoring the jumper settings.
sdn = target,lun
Program SCSI disk sdn to have the given target and
logical unit number. The target and lun of a tape or
other SCSI device may be changed by setting the sdn
variable that would be used had it been a disk. So
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tape device st7 can be set to target 4, lun 1 with
sd35=4,1.
MCD = I/O-addr:irq
I/O address (hex) and IRQ (decimal) of the Mitsumi CD-
ROM driver, by default 300:10.
TCP/IP CONFIGURATION
To use TCP/IP you have to compile a kernel with networking
enabled, and unless you are running standalone you have to
enable the ethernet driver. See the DPETHn boot variable
above. The driver supports these ethernet cards: Western
Digital 8003, Western Digital 8013, SMC Elite Ultra 16,
Novell NE1000, Novell NE2000. Many newer variants of the
WD8013, now under the SMC brand, are also supported.
You are likely to use TCP/IP in one of three situations:
Standalone with no connection to a network.
In a small network with no support from a "big" host.
Connected to a large network with address and name
servers.
In each situation you need a different set of configuration
files.
Standalone
The machine is configured with a fixed IP address:
192.9.200.1. This is one of the addresses Sun used to give
to machines without a registered network address. This
address is normally blocked at gateways, so it can do no
damage if used in a real net by accident. You need one
file, /etc/hosts, that should look like this (using the name
"darask" as an example):
127.0.0.1 localhost
192.9.200.1 darask
Small Network
In a network where the Minix machine can't obtain its IP
address and name from a different host you need specify the
ethernet address to host name translation in the /etc/ethers
file for use by the RARP daemon. Suppose you have two
machines in your network then /etc/ethers could look like
this:
0:0:c0:a:77:23 darask
0:0:c0:a:68:ce burask
Use hostaddr -e to find out what the six octet ethernet
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address of a host is. Use the address as printed: lowercase
hex digits, no leading zeros. The /etc/hosts file shows
their IP addresses:
127.0.0.1 localhost
192.9.200.1 darask
192.9.200.2 burask
Warning! Do not add ethernet addresses of diskless
workstations to your ethers file. A Sun for instance has
the stupid habit of booting from the first RARP server that
answers, probably your Minix machine...
Large Network
In a network with a central network administration your
machine's IP address and name are given by the RARP and name
services of the special servers on the network. For a new
machine you need to apply for an IP address and host name
with your network administrator supplying the ethernet
address of your machine. You don't need any configuration
files now, the irdpd and nonamed daemons automatically find
a router and a name server.
Note that no knowledge of the IP address or hostname of the
Minix machine itself is necessary, it all comes from the
RARP and name servers. A series of Minix machines can
therefore set up identically. Even if you have no RARP or
name servers you can still set them up identically if you
list all the Minix hosts in the hosts and ethers files.
Simpler configuration tools
The rarpd, irdpd and nonamed daemons are complex little
programs that try to obtain information about their
surroundings automatically to tell the machine what its
place in the network is. It should come as no surprise that
there are simpler utilities to configure a machine. On a
memory starved machine it may even be wise to configure a
machine statically to get rid of the daemons. The first
daemon, rarpd, can be replaced by:
ifconfig -h host-IP-address
to set the IP address of the machine. Note that this is
only necessary if there is no external RARP service. The
second daemon irdpd can be replaced by setting a static
route:
add_route -g router-IP-address
(if there is a router.) The last daemon, nonamed, can be
replaced by an entry in /etc/resolv.conf that specifies an
external name daemon:
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nameserver nameserver-IP-address
The ifconfig and add_route calls can be placed in the file
/etc/rc.net. The calls to the daemons will have to be
edited out of /etc/rc. Note that these changes undo all the
efforts to make Minix TCP/IP autoconfigurable. Make very
sure that all the IP addresses are correct, and that the IP
address of your machine is unique. (Mistakenly using the
address of a main server will make all other machines look
at your machine, and will make all the users of all other
machines look at you.)
FILES
/boot Minix Boot Monitor.
/minix Kernel image, or directory containing
them.
/etc/rc First of the system initialization
files.
/etc/hosts Name to IP address mapping.
/etc/ethers Name to ethernet address mapping.
SEE ALSO
monitor(8), init(8), inet(8), loadkeys(8), readclock(8),
fsck(1), update(8), cron(8), ttytab(5), getty(8),
hostaddr(1), ifconfig(8), irdpd(8), nonamed(8), rarpd(8),
hosts(5), ethers(5), set_net_default(8).
DIAGNOSTICS
Checking File Systems.
If the system has crashed then fsck is called for the
root and /usr file systems. It is wise to reboot if
the root file system must be fixed.
Finish the name of device to mount as /usr: /dev/
If the name of the /usr file system has not been set in
/etc/fstab. You can type a device name, say fd0.
hostaddr: unable to fetch IP address
TCP/IP misconfiguration. The RARP may have failed
because the ethernet address of the machine is not
entered in either the remote or the local ethers file.
Either talk to your Network Administrator, or make an
ethers and a hosts file.
1.2.3.4 login:
If you see an IP address instead of a host name then
the system failed to translate the IP address. Either
talk to your Network Administrator to have the reverse
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address translation tables fixed, or make a hosts file.
NOTES
The names "darask" and "burask" are names of cities from the
Dutch translation of the novel "The Many-Colored Land" by
Julian May. The author of this text likes names of hosts to
be things that contain people, like cities and ships.
BUGS
Indefinite hangs are possible if I/O addresses or IRQ's are
wrong. A driver may babble about addresses and IRQ's, but
that does not mean that what it says is true, it may just be
configured that way. It is very difficult to find
peripherals on a PC automatically, and Minix doesn't even
try.
AUTHOR
Kees J. Bot (kjb@cs.vu.nl)
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