# 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 (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  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 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:

              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 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)