[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Discuss-gnuradio] Losing data during long collects

From: Jeff Brower
Subject: Re: [Discuss-gnuradio] Losing data during long collects
Date: Wed, 04 Jun 2008 22:55:39 -0500


> > Is there a way for you to temporarily take file-write out of the equation?  
> > I.e. can
> > your code look at the bitstream and know if it remains continuous / intact?
> >
> > The "every minute or two" thing makes me suspicious that some HDD related 
> > thing is
> > going on.  16 MBbyte/sec is around 1 GByte/minute.
> Jeff,
> Thanks for your recommendation.  I can indeed pipe the output of my
> "data gathering app" to the input of my GPS processor and see if the
> problem goes away.

Were you able to verify that?

> However, I suspect the problem is not HDD related
> for these reasons:
> 1. I'm using a 4 disk RAID0 (external eSATA) drive that supposedly can
> handle the throughput
> 2. When I was disk bound in the past, I would receive USRP overrun
> errors.  I do not receive these errors when I am presently losing a few
> thousand samples out of every 480e6

I've seen cases before where the drive does handle the throughput as 
advertised, but
on an average basis.  Under sustained, continuous write circumstances, when the 
reaches a new sector, multiple of sectors, or some other internal space 
extra time is taken for allocation... or something along those lines.  That's 
why I
mentioned the 1 GByte figure.  It's been some time since I encountered this so 
just a shot in the dark (happened when working on high speed DSP based data
acquisition applications).


reply via email to

[Prev in Thread] Current Thread [Next in Thread]