Windows should work as expected.
QNX is probably (from a historical standpoint) using segmented with
limits and a base that is non-zero, something that doesn''t work well
with Xen... There are several of places within Xen where segments are
mismanaged (assumed to have base=0 and limit that is "big enough" [and
the latter isn''t much of a problem unless the code is incorrect in the
first place or using some "funny tricks" - but having a weird
overwriting of some memory area instead of a blue-screen/kernel panic
type situation is of course not a nice thing to have happen!]).
You do always need Dom0.
Also, real-time-ness of something running on top of Xen with full
virtualization will NOT be anywhere near "realtime", unless you play
lots of tricks with the scheduling settings on the system. And even
then, there will still be a bunch of overhead in Xen that determines the
worst-case real-time-ness. It''s probably fine if you don''t
have any HIGH
real-time requirements [i.e. your real-time-ness is in the milliseconds
rather than microseconds range].
Please DO TRY to install QNX, and let us know how it works out - it is
entirely possible that I''m wrong in my understanding of QNX and
it''s
usage of segment registers [it''s been more than 5 or more years since I
last had any connection with QNX].
--
Mats
________________________________
From: xen-users-bounces@lists.xensource.com
[mailto:xen-users-bounces@lists.xensource.com] On Behalf Of Bryan
Prosser
Sent: 31 August 2006 15:15
To: xen-users@lists.xensource.com
Subject: [Xen-users] Xen, Dual Core, Windows and QNX
I''m fairly new to both Xen and Linux, my boss wants me to try
and get Xen working on a new dual core running both Windows and QNX (we
need to do some real time processing). Ideally he wants Windows to be a
host (although from what I have read this isn''t possible yet?) and QNX
as a guest. I''m guessing a Linux Dom0 will be needed and then the
others
run as guests. Does anyone know of any issues involved with installing
QNX on Xen and getting real-time performance from it, so far ive only
run Xen on FC5 with an FC5 guest and have read the instructions on the
Zen Wiki about windows installations but don''t know how supported QNX
will be.
Any help or advice would be greatly appreciated!
Bryan
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