Handler installation instructions.

ibv2.c is the handler source code.
ibudp.c is the source code for the gpib() function.
ibup.c is the source code for the ibup() function.
ibic.c is the source code for the interactive program, ibic.

To install the handler:

1. edit conf.c (or c.c) to add the following line at the end of
   the cdevsw initializer:

	&ibopen, &ibclose, &ibread, &ibwrite, &ibsgtty, /*GPIB11V-2*/

2. make a character special file:

	/etc/mknod /dev/ib c N 0

   where N is the index of the line added in step 1.

3. edit low.s (or l.s) to add the following lines at the appropriate
   locations:

	. = 310 ^ .
		ibio; br4

	.globl call, _ibintr
	ibio:   jsr r0,call; jmp _ibintr

   where 310 should be editted to correspond to the switch selected
   vector address of the GPIB11V-2, and br4 should be editted to
   reflect the jumper selected interrupt priority level.

4. move the file ibv2.c to .../dmr/ibv2.c and edit the definitions
   at the front of the file:

   IB   should reflect the value of the switch selected Q-bus
	address of the GPIB11V-2.
   PPENAB should be made undefined to eliminate Parallel Poll code
   SAC  should be left undefined if the GPIB11V-2 is NOT the System
	Controller, and defined if it is the System Controller.
   TRI  should be 0 for open-collector buses; it may be 0 or 4 for
	three-state buses.
   EXT  is 1 for normal GPIB addressing and 2 for extended GPIB
	addressing.
   MSA  is 0140 for normal GPIB addressing and 0-036 for extended
	GPIB addressing; the value chosen in the range 0-036 is
	used to make the secondary address of the GPIB11V-2.
   MA   is a number in the range 0-036 which is used to make the
	Talk and Listen addresses of the GPIB11V-2.
   ONLYC should be left undefined if the gpib has multiple devices
	with Controller capability connected; otherwise, it may be
	defined to reduce the size of the code in a single
	Controller environment.

5. compile conf.c; assemble low.s

6. compile ibv2.c and archive it in ../lib2

7. re-load unix

To install the other software:
1. edit the devtbl[] initializer in ibup.c to contain as many devices
   as needed.

2. compile ibup.c and ibudp.c and archive in your favorite library,
   making sure that the ibup.o module precedes the ibudp.o module.

3. compile ibic.c and load with the modules archived above, putting
   the result in /usr/local/ibic.

NOTE:
A routine for cancelling posted timeouts is required by the handler
to remove unwanted timeouts which would otherwise cause the callout
table to overflow.  Since such a routine is not available in V6 Unix
one is included in the handler code.  If one already exists in your
system, simply delete the routine in the handler, and modify the handler
code to call your routine with the proper name and arguments.
