Path: utzoo!attcan!uunet!pcserver2!kdenning
From: kdenning@pcserver2.naitc.com (Karl Denninger)
Newsgroups: comp.unix.sysv386
Subject: Re: ESIX File System Selection
Summary: You can fix this too!
Message-ID: <1991Mar5.153033.11952@pcserver2.naitc.com>
Date: 5 Mar 91 15:30:33 GMT
References: <1991Jan24.033437.152@cocktrice.uucp> <1991Jan24.143542.19808@nstar.rn.com> <3021@sixhub.UUCP>
Organization: AC Nielsen, Bannockburn IL USA
Lines: 36

In article <3021@sixhub.UUCP> davidsen@sixhub.UUCP (bill davidsen) writes:
>In article <1991Jan24.143542.19808@nstar.rn.com> larry@nstar.rn.com (Larry Snyder) writes:
>
>| what type of controller?  I did have this problem on
>| one of our machines last year (running 386/ix) with
>| a WD 1006-SRV2 (1:1 16 bit RLL controller) and replacing
>| the controller (actually returning it as DOA) solved
>| the problem..
>
>  This sometimes happens with two drives on a WD 1006 or 1007 with
>multiple drives. My understanding is that an i/o is started on one
>drive while a seek is started on the other. If they both finish at the
>same time a single interrupt is issued and the driver has to check the
>controller status to get both conditions.
>
>  I was told that ISC said it was a hardware problem and SCO just
>issued the fix for the driver (xnx133). 

Turning on the flag "CCAP_NOSEEK" in the HPDD driver config file will fix
this problem with ISC machines.

I have seen it too.  It is caused by a little-used (for DOS) capability in
the WD series of controllers; that is the ability to do some operations on
two drives at once.  Specifically, you can seek one drive and while it's
moving the heads, do an I/O operation on the other.

The CCAP patch to the space.c file has fixed the problem every time I have
encountered it on ISC 2.x.

--
Karl Denninger - AC Nielsen, Bannockburn IL (708) 317-3285
kdenning@nis.naitc.com

"The most dangerous command on any computer is the carriage return."
Disclaimer:  The opinions here are solely mine and may or may not reflect
  	     those of the company.