boot - from power on to the login prompt
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
Init reads /etc/ttytab and starts a getty(8) for each enabled terminal
line to allow a user to log in.
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
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 (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
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 tape device st7 can be set to target 4, lun 1 with
MCD = I/O-addr:irq
I/O address (hex) and IRQ (decimal) of the Mitsumi CD-ROM driver, by
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.
The machine is configured with a fixed IP address: 126.96.36.199. 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
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
Use hostaddr -e to find out what the six octet ethernet address of a host
is. Use the address as printed: lowercase hex digits, no leading zeros.
The /etc/hosts file shows their IP addresses:
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...
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
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:
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.)
/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.
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).
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
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.
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 address translation tables fixed,
or make a hosts file.
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.
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
Kees J. Bot (firstname.lastname@example.org)