this directory gives a simple demonstration of how shared data works
and in fact how it can be used !!

sd.s	shared data area - will contain a few locks
	+ commons subroutines say printf read write !!

sd.h	included by sd[12].c

sd1.c	first shared data program
	read from terminal exit if an 'x' typed
	otherwise pass what was typed (via sdbuf)
	to sd2.

sd2.c	second shared data program
	wait for a message to print sd1 read the message
	and sd2 will print it as required.

mk	will make all three programs

test.c	run the two demo processes (one sd1 and one sd2)

test2.c	run the two demo processes (one sd1 and two sd2s)
	NOTE how each sd2 is using the same lock ....
	the output of each sd2 in this instance
	is garbled !!
	another lock needed !!

these programs are not meant to be definitive in useage
but merely a guide to what is possible ....

			Ian Johnstone
			6/12/77
			UNSW

