Need QNX timer and network info

Need QNX timer and network info

Post by Tycho Lamerig » Tue, 12 Sep 1995 04:00:00



We are in the process of selecting a RT OS for PC so maybe one
of you could/would fill me in a bit on the RT capabilities of
QNX. I have all the adverti*ts and read the stuff on the
QNX-site but I need more specific information.

First of all, on a normal PC (ISA or PCI bus) do you know what
timer resolution/accuracy/granularity QNX would give me? I'm
interested in, for example, repetitive interval timers (min
interval, jitter for a task tied to itimer?), interval
measurement like timer_start, do_something, timer_stop
(accuracy, granularity (us, ms) etc?)).

Also I'm very interested in the low-level networking stuff.
How do I speak with network drivers (I heard Clarkson/Crynwr
packet driver interface, correct?, but isn't that a 16 bit
interface while QNX is 32 bit?). Is there any way one can enforce
deterministic network traffic (end-to-end delays) or does QNX just
do a best effort at quickly delivering stuff?

TIA,
Tycho Lamerigts
Delft University of Technology
The Netherlands

 
 
 

Need QNX timer and network info

Post by Wayne Frankl » Wed, 13 Sep 1995 04:00:00



>First of all, on a normal PC (ISA or PCI bus) do you know what
>timer resolution/accuracy/granularity QNX would give me? I'm
>interested in, for example, repetitive interval timers (min
>interval, jitter for a task tied to itimer?), interval
>measurement like timer_start, do_something, timer_stop
>(accuracy, granularity (us, ms) etc?)).

I am not a QNX expert, but I am a developer using QNX.  As near as I've been
able to determine, timer resolution is determined by your system tick size.  
This is user configurable from 0.5 ms (milliseconds) to ????.  This tick size
only affects timers, not any other system performance, though.  There is a
note in the pub that mentions the 0.5 ms period is not available on some
slower PCs.  The quickest time, then would be 1 ms.  The default is 10 ms.

************************************

Crystal Computer Corporation

 
 
 

1. Need info for my X10 TC262 X10 powerhouse timer

I have an old X10 TC262 8-unit clock/timer with some nice
features i don't want to give up even though i bought
an activehome kit to replace the timer functions.

The sliding switch on the TC262 to select units 1-8 is flaky
and i would like to repair it myself. The problem appears to
be a broke or dislodged spring. I can't open the case to get
to it because of a plastic tab going from the plastic case
through the circuit board preventing the board from being
removed. There isn't enough room to slide it away to get it
out and and i don't want to force it.

Doea any one have any experience with this, advice or
suggestions?

thank you in advance
sol gongola

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