Included in this directory is a modified version of the
	Fermilab CD: driver from the Fall, 1982, RSX SigTape.
	The modifications are primarily to extend the driver
	to support 11M-Plus; however, they are conditionalized
	for 11M also, and provide the 11M user with the 22-bit
	support that is lacking from the original CDDRV.

	What is CDDRV?  It is a CPU-to-CPU communications package
	which allows two CPU's (PDP11's, or a PDP-11 to a VAX, once
	Fermilab's VAX version becomes available) to communicate
	using a DR11W high-speed DMA interface at each end.

	CDDRV is, in fact, really a message-switching system as well
	as a driver.  Its means of determining data packet routing
	is a user-assignable packet-type-code.  A task which is to
	receive data must declare the packet type codes which it is
	to accept; there being no conflicts with existing assignments,
	the task then becomes sole "owner," or receiver, for packets
	with those packet-type-codes.

	The driver also implements an AST mechanism which gives
	a receiver task an immediate indication when one
	of its "owned" packet types is being transmitted.
	This allows receiver tasks to "listen" for data without
	actually having to have an I/O operation pending
	until there is data to be received.

	Everything needed to build the driver should be present in this
	directory. The files should be copied to a privileged UIC,
	then CDC.CMD should be executed to set up the conditionals file,
	and CDDRV.MAK executed to build the driver.

		CDC.CMD		command file to create conditionals file
		CDPREF.MAC	prefix file
		CDDRV.MAC	driver source code
		CDTAB.MAC	database source code
		CDDRV.MAK	command file to assemble & build driver
		PN172.MEM	Original Fermilab documentation file,
				the CDDRV portion of which should apply to
				this version of CDDRV.
		PN172.RNO,.RNT,.BTC  Various files used by Fermilab to generate
				their PN172.MEM?

	The changes were developed and tested on PDP-11/70's
	and on an LSI-11/23, using MDB's DR11W interfaces, but
	they should work on Unibus systems with any of the other
	DR11W available. On a Q-bus system, however, the changes for
	22-bit mode are specific to MDB's MLSI-DR11-W board.  This is due
	to the fact that there is no standard as yet, other than MDB's,
	for extending the DR11W device registers to 22 bits.

	This version is relatively new, but so far appears to be reliable
	after about two months of experimental use.  We would appreciate
	hearing about problems, or better yet, fixes for problems you might
	find.

	For more information and for the related CDPACK subroutine package,
	refer to the Fall, 1982, RSX Sig tape; or to the latest release by
	Fermilab of their CD:-related software (look elsewhere on this tape
	for a new release by Fermilab).