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.)
          See hd(4).

     dosd = file | fat
          Choose the driver that is to be used  as  the  "DOS  virtual  disk",
          either the "file" or the "FAT" driver.  See dosd(4).

     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:mem_size  (WD80x3)
     DPETHn = I/O-addr:irq:0                  (NE2000)
     DPETHn = I/O-addr:irq:flags              (3c503)
          Set the I/O address (hex),  IRQ  (decimal),  memory  address  (hex),
          memory  size  (hex),  or  flags (hex) of the n-th ethernet board and
          turn it on.  By default  they  are  configured  as  280:3:D0000  and
          300:5:CC000  with  the  memory  size  set  to  2000,  4000,  or 8000
          depending on the type of board found.  For the Western Digital cards
          the  IRQ  must  be what the board expects, but the memory address is
          programmed into the board by the driver.  The SMC EtherEZ  board,  a
          WD8013  successor, has only 8K memory.  This confuses the driver, so
          you need to explicitly specify the board size as  being  2000.   The
          memory  address  and  size  have  no meaning for the Novell ethernet
          boards, but the address may be explicitly set to  zero  to  indicate
          that  the  board is a Novell ethernet board.  For the 3Com 3c503 the
          third parameter are flags, with the low bit indicates that  the  on-
          board  tranceiver  must  be  used  if  0 (thin ethernet), or that an
          external tranceiver is used on the AUI port if set to 1.  The IRQ is
          software  settable,  and  must be specified as 2 (XT), 3, 4, 5, or 9
          (AT).  The memory address is set  on  the  board  by  jumpers.   The
          driver  does  not  support I/O mode for the 3c503.  (Note the little
          differences  between   board   types.    For   the   8003/8013   and
          NE1000/NE2000  the IRQ is fixed and the memory address variable, for
          the 3c503 the IRQ is variable and the memory address is  fixed,  but
          need not be specified.  Messy.)

     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
          default 300:10.

     dosdn = file
     dosdn = partition:file
          Tells the DOS virtual disk driver for device dosdn (n is 0 or 5)  to
          use  a given MS-DOS file as a disk.  Depending on whether the "file"
          or the "FAT" driver is being used dosdn is either set  to  a  normal
          DOS  file name, or to a Minix hard disk partition name followed by a
          simple DOS file name.  See dosd(4).

     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 and NE2000, 3Com Etherlink II (3c503).  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.

     If rarpd notices that there is no connection to the outside world then it
     will  configure  the  default  network  to address  You need to
     create one file, /etc/hosts, that should look like this (using  the  name
     "flotsam" as the example name of the machine):


  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  rarpd.   Suppose  your
     machine  is  to be named "flotsam", and another machine in the network is
     named "jetsam".  The file /etc/ethers should at least  contain  an  entry
     for flotsam:

          0:0:c0:a:77:23   flotsam

     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 all IP addresses of the machines flotsam  needs
     to know about, and the netmask of the 10.*.*.* network:


     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

     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.

     An important parameter of a network is the netmask.  A netmask is  a  bit
     mask  that  you apply to IP addresses to find out if two IP addresses are
     on the same network.  So if a network interface has address
     with  netmask then the 32 addresses through are all on the same network as   The  rarpd
     daemon  figures  out  the  netmask  by  repeatedly looking up the netmask
     corresponding to an interfaces' network address: ip-address AND  current-
     netmask.  Suppose for example  that  the  address  for  an  interface  is    The  initial  netmask  for  this  class  B  address  is  So we  look  up  the  netmask  associated  with
     (  &  This lookup yields, so now
     look  up  to  find   Lastly  we  look  up  to find again so we use it as the netmask.
     These netmasks can be specified in /etc/hosts as follows:

     This should not be necessary on a large network that has name servers  if
     the  Network  Administrators  have  done their jobs properly.  Check with
     ifconfig if the netmask is as it should be.  If not then try to find  the
     netmask manually with host commands on the appropriate *.*.*
     names.  The initial netmask you start with is  for  a  class  A
     network  (0.*.*.*  to  127.*.*.*),  for  a  class  B network
     (128.*.*.*  to  191.*.*.*)  and  for  class   C   networks
     (192.*.*.*  to  223.*.*.*).   If  you've  found  the mistake then you can
     either try to convince your Network Administrator to fix it, or  you  can
     add the appropriate entries to /etc/hosts to please rarpd.

  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 -n netmask

     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

     Edit /etc/rc just above the point where the network daemons  are  started
     to  add  the  calls  to  ifconfig and add_route.  Remove the names of the
     daemons that no longer needed.  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.

     /etc/resolv.conf    Name resolver configuration.

     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),  resolv.conf(5),


     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. 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.

     The 10.*.*.* network can be used for  private  networks.   Next  to  this
     class  A  network  there  are  16 private class B networks, 172.16.*.* to
     172.31.*.*,  and  256  private   class   C   networks,   192.168.0.*   to
     192.168.255.*.   RFC-1597  will  tell you why they are good, and RFC-1627
     why they are bad.

     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.

     Rarpd should learn to also speak the BOOTP and DHCP protocols.

     Kees J. Bot (