How to upgrade from 1.7.x to 1.7.2.

Note: Things you have to do as root are marked with a # sign.  The ! sign
marks the actions of bin.

# Replace the sources, that's /usr/include, /usr/man, and /usr/src, with
  the 1.7.2 sources by extracting the SRC.nn images in the normal way.
  (Don't forget to move or remove the 1.7.x stuff.)

# First remove the encrypted passwords from the password file.  1.7.2
  encrypts and checks passwords differently.

! Almost all 1.7.2 compiled commands should run under a 1.7.x kernel,
  and vice-versa.  The the new stty and loadkeys commands will only run
  under 1.7.2, so make copies of them.  The old loadkeys command cannot
  run under the new kernel, so you have to compile a new loadkeys if you
  need it.  The mkfs command can only run well under the kernel it is
  compiled under.  If you follow this text point by point then the old
  mkfs will be used for 'make hdtest', and the new mkfs will be created
  once the 1.7.2 kernel is running when the commands are recompiled.

! Move to /usr/src/lib and type 'make install'.  You need new libraries
  for the new kernel.

! In /usr/src/boot type 'make install'.  The new kernel needs a new boot
  monitor.  (The 1.7.1 monitor can only boot 1.7.2 on an AT.)

# Copy /usr/src/etc/ttytab to /etc.  The ttytab file replaces /etc/ttys &
  /etc/ttytype in 1.7.2.  You need ttytab or you can't login!  Also update
  the RAM disk image if you are using the RAM disk:
  	# M root
  	# synctree /etc /root/etc
  	# U root

! If you are running 1.7.0 now then move to /usr/src/commands/simple and
  type 'make bin /usr/bin/dd'.  The next step uses a new dd option.

# The tty devices have changed in 1.7.2, so you have to create new ones:
	# cd /dev
	# sh /usr/src/commands/scripts/MAKEDEV.sh log tty00 tty01
  MAKEDEV is not installed yet, so you have to use this long name.  The
  tty0 - tty2 devices are now obsolete, you can remove them later.  If you
  have a RAM disk then update the /dev on the image as shown above for
  /etc.

! Customize /usr/include/minix/config.h to add or remove drivers.  In
  /usr/src/tools type 'make hdtest', or 'make fdboot'.  Test the new
  kernel.

! If the kernel works then go back to /usr/src/tools and type
  'make bootable' to install a new boot monitor on the root partition.

! Next use 'make hdinstall' to install an new kernel image on the root
  partition.  Reboot from the top.

! Your system is now running 1.7.2.  Use 'make install' in /usr/src to
  recompile the rest.  (Update the /bin on the RAM disk image.)

# Run 'checkhier' to check your top level directory tree.  It suggest
  commands to execute to fix descrepancies in the top level directory
  tree.  (Update /etc on the RAM disk image.)

# Compare all files in /usr/src/etc with those in /etc.  Some have
  changed and should be replaced.  Be careful not to lose changes you
  have made to files in /etc.  Remove /etc/ttys, /etc/ttytype, and
  /etc/psdatabase.  Install /etc/shadow if you want shadow passwords.
  Update /etc/passwd and /etc/shadow to the form described in passwd(5).
  (Update /etc on the RAM disk image.)

# You can remove /dev/tty[012] now.