./ed1/chg1/description
added raw (binary) line printer driver (no skip over perforations)
added accounting protection in kill and exit.
./ed1/chg2/description
added rk05 registers to error messages
./ed1/chg3/description
add Harvard tm-11 multi-file driver
./ed1/chg4/description
add Illinois fix for file names over 14 chars (return error)
add Illinois scheduler fix to use 'nice' value in determining
	swapping priorities.
./ed1/chg5/description
modify tty driver to observe xon/xoff protocol.
modify tty driver to put out bell at input of col 72.
./ed2/chg0/description
This edition is the pre-production consolidation
of all previous changes to the kernel, with the
expansion of the file tables to prevent further
occurrences of the 'no file' plague and of the
mounted file systems table to allow for the
rp06 file systems (8 per drive).
./ed2/chg1/description
This change includes the rp06 driver from NSA.
./ed2/chg2/description
This change includes:
Not being able to kill (signal 9) process 1(init).
	(or send it any signal except hangup (1)).
Removal of ptrace and profile code (sys4.c and sysent.c).
Removal of core file generation code.
./ed3/chg1/description
This version is the first production version of Unix,
designed to run on either the WP34 or 11/35 system.
In building this version, we assumed certain things:
1.  Special device codes on each system would be
constant.  I.e., /dev/mt0 would always be 800 bpi
tape, /dev/ttya-ttyp would be on dh #0.
2.  There would be only one kind of tape drive,
while there may be many kinds of disks.
3.  Each system would have certain configuration
dependent routines that were isolated in the
config directory.  When you constructed a kernel
for a system, you should recompile the entire
kernel to propagate those dependent items 
throughout all routines.
./ed3/chg2/description
Description of Edition wp0, Change 2
Removal of core file generation
Removal of ptrace code.
Removal of profil code.
./ed3/chg3/description
Description of Edition 3, change 3
Installation of Alternate block allocation algorithm.
This involves changes to:
buf.h 	a new entry in the structure
filsys.h		pad at structure end converted alternate block numbers
subr.c		block # references in bmap() changed
bio.c		altblk() added, mods to breada, bread, bwrite, and getblk
A new subroutine "altblk" is added to bio.c for alternate block
assignment. 
This change must be used with "mkfs" version 2.0 to become effective,
and then only when the filsystem is mounted.

Also implements swap error recovery algorithm.
./ed3/chg4/description
Description of Edition 3, change 4
Change /etc/init to /sys/init.
Fix 2 bugs having to do with hung processes on hangup.
	1.  When dmint routine detects a hangup it now makes
	sure it unblocks all waiting I/O, and wakes up all
	waiting on blocked I/O.
	Change is to dmint in dhdm.c.

	2.  Hangups are now given priority in the signal
	system over all other signals except KILL.  This
	prevents the DEL signal generated by spurious line
	transients at hangup from being posted over the
	hangup for that tty.
	Change is to psignal in sig.c.

	3.  3 Sep 79. Change dm open and close routines to properly
	disable scan, and check for proper stop.  Before code would
	disable scan by stuffing line register, this was causing
	other lines to go disabled.

Tune number of character (clist) buffers to system sizes.
This should prevent users from clogging the system with long
input lines, and keep lots of simultaneous I/O from being
lost.

Implement system call for system ID information.

Changed wraparound pid from 0 to 100.

Partially implemented ability to have more than 127 directories
under another directory.  Removed this change when found that
kernel uses negative number (char size) to determine end of open list.
Opened "chown" system call to use by all users.
	Possible because quota processing on our systems
	does not use the owner of files, just home directory.
Removed IBM 2741 half-duplex "feature" to save kernel space.
