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Path: utzoo!linus!vaxine!wjh12!genrad!decvax!mcnc!idis!pitt!hoffman
From: hoffman@pitt.UUCP
Newsgroups: net.unix
Subject: Re: Need help getting v7m to run on 11/23: clock problem
Message-ID: <590@pitt.UUCP>
Date: Mon, 18-Jun-84 23:01:51 EDT
Article-I.D.: pitt.590
Posted: Mon Jun 18 23:01:51 1984
Date-Received: Wed, 20-Jun-84 00:52:53 EDT
References: <1361@emory.UUCP>
Organization: Univ. of Pittsburgh, C. S. Dept.
Lines: 27

Your KWV11-C clock resembles the KW11-P clock for UNIBUS machines.
What UNIX wants is something that looks like a KW11-L 60-cycle
line clock.  That translates to a single CSR at 0177546 with exactly
two bits defined:  0200 is the 'monitor' bit, which simply alternates
between 1 and 0 every sixtieth of a second, and 0100 which is the
interrupt enable bit.  The interrupt vector is 0100.

We have used a KW11-P clock for performance monitoring by writing a
special driver for it, but have never used it as the system clock.

There are several ways to get a 60-cycle clock on your Q-bus:
	1. Buy a BDV11-AA.  This widget does all sorts of neat things,
	   including bootstrapping, diagnostics, bus termination, and
	   includes a line clock.
	2. Buy a KPV11.  This is a board designed to be used as a power
	   controller in a system with a non-DEC power supply.  It also
	   includes a line clock.
	3. Buy an Emulex SC0x disk controller.  Most of these (all?) have
	   a line clock.
	4. Buy an 11/73 CPU (KDJ11-AA).  Not only is it 3-5 times faster
	   than your 11/23, it includes a clock!
	5. Build one.  I did.  It ain't fancy but it works.

Cheers,
-- 
Bob Hoffman
Pitt Computer Science