md5sum /dev/scd0 problems

[ToddAndMargo]

Hi All,

If I turn off all my instances of virtual machines,
I can do a "md5sum /dev/scd0" on my cdrom drive
from the command line (in Linux). With a virtual
machine running, I get an input/output error, due
to Virtual XP mounting the CD in the drive.

I like the way I have my virtual machines
configured and do not want to change them.

Questions: is there a (Linux) command line
work around for this?

Many thanks,
-T