Curious, what type of machine are you seeing these messages on?  I had a
problem with lost interrupt messages on my gateway laptop whenever the
drive spun down.  The system would not recover.  I worked up a patch to the
WD driver to correct the situation, but it was pretty ugly.  Eventually I
got a BIOS upgrade (gotta love flash BIOS) and the problem went away.

Dave

> Are these something to worry about ?
> 
> /netbsd: wdc0: lost interrupt: status 50<drdy,dsc> error 0
> 
> darren