Other Technology For Review

[Bill Hacker <wbh@xxxxxxxxxxxxx>]

Folks,

DIsparate/complementary techniques for handling some of the challenges
DragonFlyBSD addresses w/r SMP and other distributed resources may be 
worth a read:

1) Xen Virtual Machine Monitor, primarily Linux-centric, but on x86
PC-grade platforms, not mainframe, and seeking transparent SMP scaling.
DragonFly may make a more suitable candidate than Linux.

   http://www.cl.cam.ac.uk/Research/SRG/netos/xen/

 - also covers modification of subordinate or 'guest' OS' to live 
without direct access
to x86 'Ring 0'.

Related research of possible interest:

'Live' migration of Virtual Machines with running processes:
 http://www.cl.cam.ac.uk/netos/papers/2005-migration-nsdi-pre.pdf

Safe sharing of physical hardware devices:
 http://www.cl.cam.ac.uk/netos/papers/2004-oasis-ngio.pdf



2) A light-weight and highly deterministic scheduling method - perhaps of
interest as SMP becomes more affordable, dual-core and 'Cell' processors 
begin to
arrive in numbers:

XOberon 'Hard Real Time' system for (primarily) machine tool and
robotics control.
  http://www.ifr.mavt.ethz.ch/research/xoberon/

Appears dormant, still has some noteworthy features, w/r efficient 
scheduling and
shared resource control.

At present/future clock and bus rates, using near-real-time tools at the 
base of kernel may ease
uncertainties of resource and communications management at higher levels.

Recommending reading for comparison, not adoption...
these are very different from whereDragonFly is / can be expected to be.


Bill Hacker