[ale] dd /dev/cdrom queryosity

[aaron]

I'm ripping some distro CD's to burn copies, eg:

       dd  if=/dev/cdrom  of=/mydir/distro1x4.iso

The CD's seem to be reading fine and the ISO's are getting generated, but dd 
is reporting an exit error after completing process:

      dd: reading `/dev/cdrom': Input/output error

The first test burn from one of the generated ISO's still seemed to come out 
OK. The byte counts of the duplicate CD match the original, and the new CD 
boots up without problems. 

According to a couple HOWTO pages, the dd command line is correct and no other 
flags or options are suggested.  I just don't recall seeing this error noted 
in the past, though I'm not sure if I've done any data rips with this 
particular CD writer, which is a fairly recent upgrade. Tried un-mounting the 
cdrom before running dd but still saw the error.

Mostly a queryosity since the ripped ISO's and resultant CD's seem to be fine, 
but any guesses as to WHY I am seeing this error?

thanks
peace
aaron