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

[Jeff Brower]

Chris-

> I'm using the USRP/DBSRX to record data for GPS.  GPS tracking demands a
> continuous stream of data -- dropped bits make tracking impossible.
> 4Msps of complex data supplies 16 MB/s -- within USB2 bandwidth and my 4
> disk RAID0 bandwidth.
> 
> I record the data using my own c++ version of cfile.  I never get an
> error or overrun condition from usrp_standard::read so it appears that
> everything is working fine.  However, when I process the data it is
> clear that data is dropped -- approximately a few thousand samples every
> minute or two.  I typically record data for one hour at a time.
> 
> I read data from the USRP in batches of 8192 16 bit short samples.
> 
> Anyone have any tips on tracking down why I am dropping data?

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