Real-Time Programming

[Guest]

I need to write a simple test. But it has to be real-time. It will show some
objects on the display and user will have to response to them by pressing
space key, for instance. I know that Windows XP is not a Hard Real Time
System. Is it possible to make it? I tried to use RTOS by Venturcom, but it
doesnt have GUI. I have CeWin, but I dont really understand if it's possible
to use it. Any suggestions? May be you know what RTOS I can use to accomplish
this task. Thank you...

 

[frodo]

I need to write a simple test. But it has to be real-time. It will show some
objects on the display and user will have to response to them by pressing
space key, for instance. I know that Windows XP is not a Hard Real Time
System. Is it possible to make it? I tried to use RTOS by Venturcom, but it
doesnt have GUI. I have CeWin, but I dont really understand if it's possible
to use it. Any suggestions? May be you know what RTOS I can use to accomplish
this task. Thank you...

Well, your app doesn't sound like it's "too" real-time. Have you set the
Multimedia Timer in your app? By doing so you can lower interrupt latency
to less than a millisec, which aught to do fine for you. Note that all
that you need to do is init and set the MM Timer in your app, you don't
actually use the timer, nor its event; simply setting its resolution to 1
mSec has the side effect of lowering the overall system-timer resolution
too. read msdn, and these:

http://www.opcware.com/XtraTimer/MultimediaTimers.html

http://discuss.joelonsoftware.com/default.asp?joel.3.224702.15

there's more out there too, google for "soft realtime windows"

 

[Guest]

Well, your app doesn't sound like it's "too" real-time. Have you set the
Multimedia Timer in your app? By doing so you can lower interrupt latency
to less than a millisec, which aught to do fine for you. Note that all
that you need to do is init and set the MM Timer in your app, you don't
actually use the timer, nor its event; simply setting its resolution to 1
mSec has the side effect of lowering the overall system-timer resolution
too. read msdn, and these:

http://www.opcware.com/XtraTimer/MultimediaTimers.html

http://discuss.joelonsoftware.com/default.asp?joel.3.224702.15

there's more out there too, google for "soft realtime windows"

I need hard real-time, as I need to record the time when object was shown
and when user responded to it, I need a determinism here. I will have a great
number of test, and I will need to biuld statistic using results.
Thank you...

 

[V Green]

I need hard real-time, as I need to record the time when object was shown
and when user responded to it, I need a determinism here. I will have a great
number of test, and I will need to biuld statistic using results.
Thank you...

Program in DOS, or, even better
x86 assembly language.

Lower system overhead.

XP is FAARRR too busy with other things
(housekeeping) to respond in "hard" real-time,
every time.