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From: aryeh@eddie.MIT.EDU (Aryeh M. Weiss)
Newsgroups: comp.unix.xenix
Subject: Re: Need help w/Apparat Ram Card with Microport 2.2
Message-ID: <6143@eddie.MIT.EDU>
Date: Sun, 21-Jun-87 08:54:06 EDT
Article-I.D.: eddie.6143
Posted: Sun Jun 21 08:54:06 1987
Date-Received: Mon, 22-Jun-87 06:42:29 EDT
References: <114@qetzal.UUCP> <6120@eddie.MIT.EDU> <117@ddsw1.UUCP>
Reply-To: aryeh@eddie.MIT.EDU (Aryeh M. Weiss)
Organization: MIT, EE/CS Computer Facilities, Cambridge, MA
Lines: 44
Keywords: double fault panic 256k dram 64k dram
Summary: Fixes for uport unix 80287 crashes and clock problem

In article <117@ddsw1.UUCP> karl@ddsw1.UUCP (Karl Denninger) writes:
>In article <6120@eddie.MIT.EDU>, aryeh@eddie.MIT.EDU (Aryeh M. Weiss) writes:
>> Also, users of Microport UNIX will be glad to know that the 80287
>> floating point crash (system hangs when there is a floating point
>> error) has been fixed, and the patch has been sent to uport for inclusion
>> in their next release. Also, the clock problem has been fixed.
>
>
>Note: 2.2.2's release notes still list the 80287 bug as an open problem.
>
The clock fix and 80287 fix are quite new, were done in our lab and
forwarded to Microport. They should be included in the next release.
I will briefly describe them, but you will need a source licence to 
fix them yourself.

In clock.c (rel.2.2/i*/i*/os) remove the first two #ifdef IBMAT, except to
move time++ out of the second one into the regular code. This removes the
kludges with which Microport tried to "fix" the problem. Also, set 
RTCCNT (/usr/include/sys/clock.h) to 19885 (decimal).

In trap.c (same directory) add the following line

		outb (0xF0, 0);	/* M001 - Clear busy condition */

after the asm ("   fnclex") instruction (there is only one of them).

Having done this,  run make in that directory to get a new lib1, and
then make a new kernal. After you have installed the new kernal, use
/etc/patch to check .clocktic -- it should be 19885. If it is not, patch it.
This value may need tuning if your system has slightly differnet internal 
oscillators.
It was very nice to force a divide by zero and have the system dump core
and return cleanly...

The system is running well (no obscure compiler errors) with the 4 Meg
Micron extended memory board at 10 MHz 1 Wait state. However, it did
not run properly at 8 MHz 0 wait states. I wonder if other people with
clones based on the Chips and Technology chip set have had such 
problems (mine is a Wells A*Star II).


-- 
aryeh@eddie.mit.edu
mit-eddie!lees-rif!aryeh