

			DD README FILE

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Version v2.0: 
=============
CW May 18, 1995: only three weeks left before I go
		hiking in  Pakistan!!!

Added:	- Tcl/Tk user interface dd_ui, dd_fifo_mon
	- better handling of detaching processes
	  when they crash (using semaphores to
	  decide whether the process is still around)
	- fixed minor bug in dd_dcom when a process
	  attaches only (but has not a fifo).
	- add user guide 



Version v2.1: 
=============
Three major changes:
1. performance tests done at CEBAF showed that the
	DD is rather slow (1000 ev/sec).
	How to speed up?

	a) SGI Performance analyzer reveals
	several problems:
	- ddu_attached() is called from several
	places for each event and turns out to
	be very time consuming (ftok, shmget and
	getenv).
	change such that it is only called
	when dbfi_get/put_fev reports an error
	- dd_attached:
	new routine, is called every time before
	dbfi and checks whether dd_dcom is still
	around. ddu_attached is no longer called
	before dbfi_put/get_fev
	- because of these two changes, must 
	add some code for graceful exiting...


2. producer and consumer can now change their
	dd wait mode back and forth between
	sleep and async.

3. directory structure for different oper. sysstems

