[hpsdr] Penelope PTT

[Gerd Loch]

Hi Bill,

I really like your objective answer.
I already supposed that your intention was to protect the power amplifier
which is of course reasonable.
However I believe that a moderate timeout of about a second would not harm
the hardware in case of ...

Probably I will follow your advice and change to XP. I have it here for
about a year but I hate to reinstall a lot of programs and utilities with
which it always ends up when changing the os.
I rely on your statement that the USB2 stack has a much better performance
with XP.

73, Gerd
DJ8AY



-----Ursprüngliche Nachricht-----
Von: Bill Tracey [mailto:bill at ewjt.com] 
Gesendet: Dienstag, 19. August 2008 20:58
An: g.loch at nt-electronics.de; 'Phil Harman'
Cc: hpsdr at hpsdr.org
Betreff: Re: [hpsdr] Penelope PTT


You're not going to like my answer, but I'd say use Windows XP.  The 
USB2 stack in Win2K is a bolt on and it's performance is 
miserable.  During the original development of Ozy and Janus I ended 
up moving to XP to get away from perf issues in the Win 2k USB2 
stack.  Moving to XP made things much better.

The reason for making PTT dependent on HAVE_SYNC was to avoid leaving 
an external amp keyed down in the case of the PC hanging up and going 
away.  We're trying to have the hardware do the right/safe thing even 
if the PC blows up.  That being said, I don't think  we need to 
declare the PC broken after 1 lost sync, think adding some sort of 
moderate timeout in there to deal with a occasional dropped frame 
would be a good thing.

One other suggestion - try running PowerSDR at higher than normal or 
real time priority (there's a drop down for priority in the setup pages).

Regards,

Bill (kd5tfd)

At 01:55 AM 8/19/2008, Gerd Loch wrote:
>***** High Performance Software Defined Radio Discussion List *****
>
>Hi Phil,
>
>Of course you are right that this will only cure the issue but I doubt 
>that you can totally avoid dropouts in the system Windows-USB. I am 
>running W2k and my cpu load ist somewhere about 25% and I am not 
>willing to run PowerSDR exclusively on this PC. I always had poppings 
>and I do not know how I could avoid them in practice. Maybe you can 
>reduce the number per timeunit. USB is not realtime. On the other side 
>what is the practical use of making PTT dependent on HAVE_SYNC so that 
>this workaround would not make sense?
>
>Can you offer a concept how to totally avoid the fifo running empty?
>
>73, Gerd
>DJ8AY



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