[pups] Progress on 2.11BSD kernel
dfevans at bbcr.uwaterloo.ca
Thu Mar 20 09:15:16 AEST 2003
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).
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
More information about the TUHS