From: utzoo!decvax!harpo!seismo!hao!hplabs!sri-unix!ask.ISL@Sumex-Aim
Newsgroups: net.unix-wizards
Title: Re: uba0: too many zero vectors
Article-I.D.: sri-arpa.889
Posted: Mon Mar 28 19:56:00 1983
Received: Mon Apr 18 23:58:55 1983


	I experienced a similar problem while trying to install an AED512
DMA interface on our 11/780 running 4.1BSD.  The problem was that the
NPR jumper was not removed (the default is NPR installed) on the Unibus and
this led to the bypassing of the device when a bus grant was made.  Thus the
CPU sees no interrupt vector.  This happens at boot-time  whenwhen all the
devices on the bus are recognized and their addresses etc. are loaded.

When the NPR jumper was removed, the problem went away.  To find out 
which pins correspond to the jumper, check the Unibus descriptions 
(my recollection is that the pins are CA1-CA2, but I am not quite sure).
					
						   Krishna
					Information Systems Lab.
					   Stanford University

						ask@SU-DSN.ARPA or
						ask@SU-ISL.ARPA
				(I think this is how I can be reached)