Re: [Discuss-gnuradio] Losing data somewhere between USRP and hard drive

[Chris Stankevitz]

Hi,

Thanks for your response.  I would still like an answer to this question:

> Q1: If I use a usrp_rx_cfile.py  to record data, and my app never reports 
> "Ou" on the console, have all the bits been written to disk?

> usrp_rx_cfile.py is known to work ;)

No doubt about it, but if the hard drive cannot keep up, I'm sure data 
will be lost.  My goal is to setup a system that can record data to disk 
even with a slower hard drive, perhaps by creating a threaded file_sink 
with a large memory buffer.

ubuntu 32 bit, with ext3.  I will try ext2.

> Have you tried benchmarking your filesystem i/o throughput?
> How about testing for any "pauses" where nothing else can get done.
> E.g., posting the ext3 journal.

I'm running on a laptop and I suspect I am going to have problem with 
hard drive speed and my solution will need to be in the "application 
layer."  But I will play with hdparm and family.

> 16MB/s * 8 bits/byte = 128Mbit/s
> Are you using gigabit ethernet?

Yes.  Network has plenty of room to spare according to "task manager." 
Using crossover cable.  The mystery here is why would gr give "Ou"s when 
sending data over gigabit to a server that simply throws the data away. 
 These Ous happen far less than the hard drive Ous.

Thanks again for your help,

Chris