Incomplete FAQ? What is an 'i' underrun?

GNU Radio
1

I have been getting a lot of ‘iU’ outputs when I run my scripts, and I
found in the FAQ (here: http://gnuradio.org/trac/wiki/UsrpFAQ/Gen)
that:

"u" = USRP
"a" = audio (sound card)
"O" = overrun (PC not keeping up with received data from usrp or

audio card)
“U” = underrun (PC not providing data quickly enough)

aUaU == audio underrun (not enough samples ready to send to sound

card sink)
uUuU == USRP underrun (not enough sample ready to send to USRP sink)
uOuO == USRP overrun (USRP samples dropped because they weren’t
read in time.

So what type of underrun does the ‘i’ represent?

Jason

2

Looks like you’re using Mac OS X :wink: If you’re not, then please let
the list know what OS you’re using & ignore the rest of this message.

That "iU’ should get fixed, since it’s not in-line with that the FAQ
states those “codes” should be. It signifies that there is a read
overflow on the USRP, so it should instead read “uO”. For more info
load up “usrp/host/lib/legacy/fusb_darwin.cc” and then search for “iU”.