From mboxrd@z Thu Jan  1 00:00:00 1970
From: dfevans@bbcr.uwaterloo.ca (David Evans)
Date: Wed, 19 Mar 2003 18:15:16 -0500
Subject: [pups] Progress on 2.11BSD kernel
In-Reply-To: <200303192308.h2JN8kD04865@moe.2bsd.com>; from sms@2BSD.COM on Wed, Mar 19, 2003 at 03:08:46PM -0800
References: <200303192308.h2JN8kD04865@moe.2bsd.com>
Message-ID: <20030319181516.A18264@bcr10.uwaterloo.ca>

On Wed, Mar 19, 2003 at 03:08:46PM -0800, Steven M. Schultz wrote:
> >   OK.  From what I recall (that turned-off machine again...) the entire
> > discussion on tuning MAXUSERS and friends is based on allocation of UMRs.
> > Might be a good idea to slip in a note about what to do when you don't have
> 
> 	It is less a matter of MAXUSERS than it is of NBUF.   NBUF sets
> 	the number of disc cache buffers.

  Yeah, sorry, it was NBUF that I was thinking of.  It's been aboutn a month
since I've had a chance to fiddle with my /73.

> 	The other constraint, even for Qbus systems, is the D space requirement.
> 	The 1KB portion of the disc buffer is "external" to the kernel (is 
> 	mapped in/out as needed) but there is a header structure which is
> 	part of the kernel's permanent address space.  Each buffer header is
> 	24 bytes so even without UMRs around it's not feasible to have a 200KB
> 	cache because that'd use 4800 bytes of kernel D space (which is always
> 	on the edge of being overflowed it seems).
> 

  Cool, thanks.

-- 
David Evans          (NeXTMail/MIME OK)             dfevans at bbcr.uwaterloo.ca
Ph.D. Candidate, Computer/Synth Junkie     http://bbcr.uwaterloo.ca/~dfevans/
University of Waterloo         "Default is the value selected by the composer
Ontario, Canada           overridden by your command." - Roland TR-707 Manual