Re: [rtl] stability of OS clock

["Norm Dresner" <ndrez@att.net>]

A friend of mine wrote a demonstration program which was an NT ring-0 kernel driver which just toggled the voltage at the internal
speaker;  when the machine was quiescent, the speaker emitted a constant 1 KHz hum.  As soon as he started to move a window around
on the screen the frequency dropped and if the window was moved fast enough it sounded like the speaker stopped completely.  There's
no possible way to do hard real-time programming in NT because the wrong tasks have the highest priority: screen update is higher
than a kernel timer!

If you can disconnect the keyboard and mouse and guarantee that no other tasks are running, pseudo real-time is possible in NT.  But
I wouldn't use it for anything the least bit important.

Norman Dresner
Fellow Avionics Support Systems Engineer & (SGI) Advanced Signal Processing Laboratory Administrator
Radar Systems Engineering Department
Electronic Systems and Sensors Segment
Northrop Grumman Corporation
Baltimore-Washington International Airport
7323 Aviation Boulevard
Baltimore Maryland 21240

Voice: (410) 993 - 2096 Mornings; all-day voice-mail
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----- Original Message -----
From: <dzambotto@infinito.it>
To: <rtl@rtlinux.org>
Cc: <dzambotto@infinito.it>
Sent: Wednesday, September 05, 2001 9:32 AM
Subject: [rtl] stability of OS clock


> Dear All:
>        I have two questions:
>         1. Is there a tool or someone else that compare            rtlinux and windows NT on realtime (I want              to use
win NT for control a device and I                want to know if the clock of NT is stable or            not!);
> 2. If there isn't a tool, how can I try to test        the effectivness stability of the clock of    win Nt?.
> Thanks for all.
> Demis
>
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>
>
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