Re: [Discuss-gnuradio] High Data rate File Sink dropped data

[Marcus D. Leech]

On 08/02/2011 08:11 PM, Tom Rondeau wrote:
> On Mon, Aug 1, 2011 at 10:24 AM, Jason Thomas<address@hidden>  wrote:
> > I am trying to record data directly from a UDP stream to file. I have four
> > channels at 1.2MHz sample rate the code is below. Basically it opens a UDP
> > source and connects to a file sink. However, It is losing data when writing
> > to the file. If I stream a signal with a one second burst the spacing is not
> > correct. Also, I have another c++ program that reads the UDP packets and
> > records directly to file, and there are no lost UDP packets nor lost data
> > with this program. Also I have checked that the UDP packet size is less than
> > 1472, it is currently at 1024 bytes.
> >
> > Is there a way to see if file_sink is not able to handle that data rate, or
> > to see if the UDP source cannot keep up?
>
> It's most likely that your disk is not able to keep up. I've used GNU
> Radio's file sink to save gigabytes of data at 25 MHz float I&Q, but I
> used a RAID5 device to do it. You probably need more spindles.
>
> Tom
Tom:

It's not strictly disk-limited, since Jason observes that with a non-Gnu 
Radio program, he can record direct to disk from
  the raw UDP stream, and not lose anything.




--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org