Short list of differences between 1.7.2 and 1.7.4:

  - Second level file system cache.  Makes 286 based AT's happy and
    does away with the RAM disk for normal use.  The "scratch" partition
    is also obsoleted.

  - All the commands using <sgtty.h> have been changed to use <termios.h>.
    The this means that the entire system is now supposed to be as POSIX
    compliant as can be achieved given Minix limitations as a simple
    educational system.

  - File system limit upped to the somewhat arbitrary maximum of 1 Gb
    thanks to doing away with preloaded bitmap blocks in FS.  16-bit
    fsck is still limited to 128 Mb.

  * Virtual Consoles are now standard.  The default kernel has two defined.

  (Things marked with a '*' were changes from the deadborn 1.7.3 to 1.7.4.)

Contributions:

  Richard Henderson <rth@tamu.edu>
	Bitmap block code changed to no longer preload bit map blocks.

  Kouichi Hirabayashi <kh@mogami-wire.co.jp>
  Saeko Hirabauashi
	New AWK program and fix to calendar.

  Paul Ashton <paul@cosc.canterbury.ac.nz>
	Many alignment problems, null pointer dereferences, string constant
	writes and network code bug reports and fixes.  (Does SunOS-Minix).

  Albert S. Woodhull <awoodhull@hampshire.edu>
	Speling error fixes, extra code comments, code rearrangements.
	General pain in the neck.  (Does the new Minix book in co-op
	with Andy.)

  Michael Temari <temari@ix.netcom.com>
	Updates to his network programs.  Mktime() fix.

  Christophe Lizzi <lizzi@ecoledoc.ibp.fr>
	French keyboard map checked and fixed.

  Osamu Ishibashi <NCD02424@niftyserve.or.jp>
	Change to let the Adaptec driver know Magneto Optical disks.
	Repaired long standing bug in XT wini.

  Chr <root@pc1.fa1.cie.uva.es>
	Security bug report on the recover command.

Long list of differences between 1.7.2 and 1.7.4:

  (Warning: This list is riddled with lame jokes and other silly things that
  happen to sneak in when doing something as boring as compiling this list.)

  include/curses.h
	<sgtty.h> -> <termios.h> by porting it back from Minix-vmd.

  include/limits.h
	UINT_MAX and ULONG_MAX changed to hex constants like 0xFFFFFFFF to
	make gcc stop complaining.

  include/minix/config.h
	[IZ]_MAP_SLOTS made obsolete and thus removed.
	ENABLE_CACHE2 added to enable or disable the second level cache.
	ENABLE_COMPAT removed
	ENABLE_BINCOMPAT added to enable or disable support for old binaries
	using obsolete system calls.
	ENABLE_SRCCOMPAT added to enable or disable support for old sources
	using obsolete system calls.
*	NR_CONS can now be 1 to 8 to enable virtual consoles.

  include/minix/const.h
	SIG_PUSH_BYTES removed, because the old V7 signal code support is
	removed.  (Software emulation of signal() still present.)

  include/signal.h
	SIGSTKFLT removed (unused).
	SA_COMPAT removed (old signal).

  include/stdio.h
	Definitions for vfscanf(), vscanf(), and vsscanf() added.

  include/string.h
	char * -> void * for bcopy(), bcmp(), and bzero().

  include/sys/ioctl.h
	Final touch to the <sgtty.h> -> <termios.h> changeover, TIOCGETP
	etc. now defined to use higher level emulation calls (SRCCOMPAT)
	instead of the old "pack it into a message" calls (still emulated
	under BINCOMPAT.)

  include/sys/sigcontext.h
	struct sigframe moved into here from kernel/system.c.

  include/sys/types.h
	zone_t, block_t, and bit_t changed to unsigned types to avoid type
	bug problems (and possible invite new bugs).

  include/tiny-fcntl.h
  include/tiny-unistd.h
	Removed in favour of the normal include files.

  man/cat2/fcntl.2
	Removed in favour of a new man2/fcntl.2.

  man/man0/as
  man/man0/awk
	New manual pages derived from the Reference Manual.

  man/man0/fsck
	Mention fsck1 as the V1 file system checker.

  man/man0/kermit
	Removed some nonsense about "set the line speed before starting
	kermit".  POSIX termios ttys always reset on close, so a terminal
	program must set the line itself.

  man/man0/ls
	Adapted to tell that -l now lists the group by default.

  man/man0/mkfs
	The maximum file system size is 1 Gb.

  man/man0/sh
*	Made it look good on a screen thanks to lots of '.ti' nroff things.

  man/man0/users
*	Removed

  man/man1/synctree.1
	Spellchecked by an American, who, unlike most Americans, can spell
	better then me.  :-)

  man/man1/vol.1
	Explain that vol can now do without the volume size argument if
	the volume size equals the floppy size.  Also allows mixing of
	floppy types within one vol run.

  man/man2/fcntl.2
	A new manual page for fcntl() listing all the gory details.

  man/man4/console.4
  man/man4/dev.4
	New manual pages describing the console in particular and all devices
	in general.
*	Added info about Virtual Consoles.

  man/man8/add_route.8
  man/man8/pr_routes.8
	Describes the command to specify fixed network routes, and a command
	that lists the TCP/IP driver's routing table.

  man/man8/usage.8
	Explains the new situation with the 2nd level disk cache.
*	'Setup' (formerly instdist) can now run after migrating to disk
	to install floppy sets.
*	A few words on Virtual Consoles added.

  src/boot/
	As usual things changed, but its mostly Minix-vmd related.

  src/commands/aal
	/usr/bin/aal is linked to /usr/bin/ar on installation.  Same
	situation as on 68000 based machines.
*	Added proper <stdarg.h>/<varargs.h> code.

  src/commands/advent/verb.c
	There was some confusion over what should happen if you meet the
	bird carrying a rod.  (Or maybe there wasn't any confusion except
	with me.)  Anyway, I unchanged the change made between 1.7.1 and
	1.7.2.  I demand a screen dump of a PDP-11 adventure game in action
	before I change it again.

  src/commands/awk
	This is a replacement of bawk.  Not tested much, but compared to
	bawk it must be infinitely better.

  src/commands/awk/m.c
*	Null pointer dereference bug fixed.

  src/commands/bawk
	"Dead.  All of them.  And good riddance."  -- Londo Mollari.

  src/commands/de/
	[IZ]_MAP_SLOTS, <sgtty.h> out, <termios.h> in.

  src/commands/elle/
  src/commands/elvis/
	<sgtty.h> out, <termios.h> in.

  src/commands/ftp/
*	New and improved ftp command.

  src/commands/ftpd/
	Our network application Guru is making this more useful by the day.

  src/commands/ibm/cdplay.c
  src/commands/ibm/mixer.c
  src/commands/ibm/part.c
  src/commands/ibm/recwave.c
	<sgtty.h> out, <termios.h> in.
	Geometry guessing code added to 'part' to crosscheck with what the
	device driver claims.

  src/commands/ibm/term.c
	Nothing IBM dependend here, so moved to ../simple/.

  src/commands/ic/ic_input.c
  src/commands/kermit/
  src/commands/mined/
	<sgtty.h> out, <termios.h> in.
*	Mined: fixed varargs bugs by using <stdarg.h>/<varargs.h>.

  src/commands/m4/main.c
*	Write to a string constant bug fixed.

  src/commands/patch/patch.c
*	Null pointer dereference bug fixed.

  src/commands/scripts/DESCRIBE.sh
	Describe "virtual console" devices.

  src/commands/scripts/checkhier.sh
	Also check setuid or setgid binaries.

  src/commands/scripts/instdist.sh
	Added support for an "upgrade", i.e. move contents of /usr into
	/usr/.old and extract new stuff on the old file system.
	No longer make a scratch subpartition.
	Install using a second level file system cache.
*	Renamed to `setup'.

  src/commands/scripts/mkdist.sh
	Adapted to the new situation where /minix is a directory.

  src/commands/scripts/setup.sh
*	New name for instdist.sh.  When setup is run when Minix is already
	on disk it now offers to unpack a floppy set.  /usr is now filled
	this way, not at the early installation phase.

  src/commands/sh/sh3.c
	Fixed an exit status bug.  (Can't remember the details.)

  src/commands/simple/animals.c
	<sgtty.h> out, <termios.h> in.  (This is getting boring.)

  src/commands/simple/calendar.c
	Bug fix by the author.

  src/commands/simple/chmod.c
	Don't stop on the first error, try all files.

  src/commands/simple/chown.c
	Simplified a bit assuming that chown is never setuid-root.

  src/commands/simple/cmp.c
*	Wrong use of perror() changed to right use of strerror().

  src/commands/simple/comic.c
	Removed before anyone thinks it is useful.  (Good compression
	program that is no longer so good compared to things like gzip.)

  src/commands/simple/df.c
	Return a useful exit code.

  src/commands/simple/diskusage.c
*	Changed 'struct stat *this_stat' to 'struct stat this_stat'.  It
	helps if an object actually exists.

  src/commands/simple/ftp.c
*	Replaced by src/commands/ftp/.

  src/commands/simple/getty.c
	Better protection against user abuse.

  src/commands/simple/gomoku.c
	<sgtty.h> out, <termios.h> in.

  src/commands/simple/in.rshd.c
	New version from Minix-vmd containing various fixes.

  src/commands/simple/join.c
*	Various null pointer dereference bugs fixed.

  src/commands/simple/leave.c:
*	Some kind of DST problem fixed.

  src/commands/simple/life.c
	<sgtty.h> out, <termios.h> in.

  src/commands/simple/login.c
	Better protection against user abuse.

  src/commands/simple/ls.c
	Default of 'ls -l' is now to also list the file group.  Cleanup.

  src/commands/simple/men.c
	<sgtty.h> out, <termios.h> in.
	Calls to the obsolete 'getlf' changed to 'echo;read'.

  src/commands/simple/mkfs.c
	Z_MAP_SLOTS things removed.  Max file system size set to 1 Gb.

  src/commands/simple/modem.c
	Copied from Minix-vmd.  From useless to possibly useful?

  src/commands/simple/recover.c
*	Glaring security bug fixed.

  src/commands/simple/rlogin.c
	<sgtty.h> out, <termios.h> in.  Non-Minix code deleted.

  src/commands/simple/roff.c
	<sgtty.h> out, <termios.h> in.  Why does a text formatter need
	terminal parameters?

  src/commands/simple/sed.c
	Added \:xxx: that is equivalent to /xxx/, but allows you to choose
	the delimiter, ':' in this example.  Null match loop and exit code
	bug fixed.

  src/commands/simple/tcpd.c
	Added -DPARANOID for the truely paranoid that demand heavy logging.

  src/commands/simple/term.c
	Moved in here from ../ibm/.
	Revamped interface.  Type `CTRL-] h' to see how.  Very useful in
	combination with ZMODEM (rz/sz).  I ditched kermit in favour of
	this new term.

  src/commands/simple/test.c
	<sgtty.h> out, <termios.h> in.  (For 'test -t')

  src/commands/simple/time.c
	return((status & 0377) ? -1 : (status >> 8));   What else?

  src/commands/simple/users.c
*	Removed because it is both broken and useless.

  src/commands/simple/vol.c
	Allow one to omit the volume size for floppies.  Vol will ask the
	floppy driver how large the floppy is and act accordingly.
	My apologies to Andy for making one of his programs Big & Ugly.

  src/commands/simple/write.c
	<sgtty.h> out, <termios.h> in.
	Setgid 'tty' to allow writing to terminals that are now mode
	620, group tty by default.  Prevents misuse.

  src/commands/telnet/ttn.c
	<sgtty.h> out, <termios.h> in.
	Used to always used local port 1234 preventing two simultaneous
	telnets.

  src/commands/simple/yes.c
*	String constant write fixed.  (In one of my programs.  *deep shame*).

  src/commands/telnetd/
	Fixes by our network program wizard.

  src/commands/yap/
	<sgtty.h> out, <termios.h> in.
	Yap should not write to string constants, as one SunOS-Minix
	found out after he made text and string constants read-only.

  src/commands/zmodem/
	You know the drill: <sgtty.h> out, <termios.h> in.

  src/etc/fstab
	tmp=/dev/TMP line removed.

  src/etc/protocols
*	Initial /etc/protocols file; list of tcp, udp, etc protocol numbers.

  src/etc/ttytab
*	Added Virtual Console devices.

  src/fs/buf.h
	I_MAP_BLOCK and ZMAP_BLOCK definitions replaced by MAP_BLOCK using
	a lax writing policy.  (Map blocks can be restored easily by fsck.)

  src/fs/cache.c
	Calls to transfer blocks to/from the second level cache added to
	normal cache routines.  #if ENABLE_CACHE2 armour to allow it to be
	configed out.  (And out of the book listings.)
	Calls to alloc_bit() and free_bit() changed to use a new interface.

  src/fs/cache2.c
	The second level block cache.  The code in this file writes any
	block expelled from the normal block cache somewhere into the
	RAM disk.  A small list is kept that records where blocks went.
	Note that this is a read-only cache, so writes are still slow.
	This cache mainly helps by caching executables.  This helps
	compilations and shell scripts a lot.  Useless on the 386 where
	you can simply use a very big normal cache.

  src/fs/inode.c
	Changed alloc_bit() and free_bit() calls.

  src/fs/mount.c
	Do not load or unload bit map blocks anymore.

  src/fs/protect.c
	Third argument of forbidden() done away.

  src/fs/super.c
	Load_bit_maps() and unload_bit_maps() removed.  Alloc_bit() and
	free_bit() rewritten to get or put bit map blocks as needed.  This
	means that bit map blocks no longer claim a large portion of the
	block cache.  Unused file systems can be kept mounted without cost.
	More file systems can be mounted.

  src/fs/super.h
	*s_imap[I_MAP_SLOTS] and *s_zmap[Z_MAP_SLOTS] memory eaters removed.

  src/inet/
	Various uninteresting changes.  Can be compiled with -DDEBUG now.

  src/kernel/
	Several little changes and code rearrangements.

  src/kernel/aha_scsi.c
	Magneto-Optical disks superficially recognized as some kind of disk.  
	Prevent/allow medium removal left on the TODO list.

  src/kernel/console.c
*	Virtual Consoles.

  src/kernel/keyboard.c
*	A few changes to allow one to select a Virtual Console.

  src/kernel/keymaps/french.src
	Checked and fixed by someone whose feet are rooted in solid French
	soil instead of sticky Dutch clay.

  src/kernel/klib*.s
	Old signal() needed build_sig(), so it is gone.
	25 microsec delay added to the 16-bit A20 line toggling code.

  src/kernel/system.c
	Support for old signal() (SYS_OLDSIG) removed.
	Struct sigframe moved to <sys/sigcontext.h> so it can be used in
	the library.

  src/kernel/tty.c
	ENABLE_SRCCOMPAT or ENABLE_BINCOMPAT placed around various bits
	of <sgtty.h> emulation code.
*	Speaks of "16-bit", or "32-bit" mode now, instead of "protected"
	or "386" mode.  Using "386" sounds to retarded to people running
	this on their super fast Pentium.  Does not help to sell books.
	Bloody Politics.

  src/kernel/xt_wini.c
	Living in the country where the Sun rises first apparantly allows
	one to see better.  XT wini now works.

  src/lib/ansi/errlist.c
	Spelchecked so that eror messsages dont look stoopid anymore.

  src/lib/ansi/memcmp.c
	Characters are unsigned to memcmp() says ANSI.

  src/lib/ansi/mktime.c
	Bug computing across the start of a month fixed.

  src/lib/ansi/strcmp.c
  src/lib/ansi/strncmp.c
	Unsigned characters.

  src/lib/curses/
  src/lib/editline/
	<sgtty.h> out, <termios.h> in.

  src/lib/ip/gethostent.c
	Alignment problem fixed, you can't write a long into a char array.

  src/lib/ip/rcmd.c
	rcmd() expects needs a network byte order port number, not host
	byte order!  Sleep(1) added as a hack so that we do not listen
	too soon, or something.

  src/lib/ip/res_mkquery.c
*	Assignments to dh_flags[12] changed to '|=' where there was '='
	by mistake.  Caused overwrite of earlier assignments.

  src/lib/other/bcmp.c
  src/lib/other/bcopy.c
  src/lib/other/bzero.c
*	`char *' changed to `void *'.

  src/lib/other/getpass.c
	Replaced by the Minix-vmd version that uses <termios.h> and is
	more disaster-proof.

  src/lib/posix/_gtty.c
  src/lib/posix/_stty.c
	Very old <sgtty.h> calls removed.

  src/lib/posix/_ioctl.c
	Old <sgtty.h> "pack it in a message" code removed.

  src/lib/posix/_isatty.c
	<sgtty.h> out, <termios.h> in.

  src/lib/posix/_readdir.c
	(char) -1 need not be negative.

  src/lib/stdio/perror.c
	Fixed to get the error string before destroying to with fprintf()!

  src/lib/stdio/vscanf.c
  src/lib/stdio/vsscanf.c
	New functions.

  src/mm/alloc.c
	Mem_left() obsolete and removed.

  src/mm/break.c
	Stack_fault() obsolete and removed.

  src/mm/forkexit.c
*	Let fork() return ENOMEM if out of memory instead of EAGAIN.  (This
	is debatable, some systems returns EAGAIN if memory could come
	available in the future, and ENOMEM if there is certainly not
	enough memory ever.  But ENOMEM leads to a better error message.)

  src/mm/signal.c
	Old signal() removed.

  src/mm/utility.c
	Find_proc() obsolete and removed.

  src/test/
	Why do test programs have more bugs themselves than they help fix?

  src/tools/mkboot
	Manage a /minix directory for kernel images instead of the scratch
	test boot partition.