This will make the SunRay slim clients more useful: You can attach all kinds of USB mass storage devices to the SunRay USB ports. E.g., if you have your USB key chain drive, you can connect it and it will be automounted in
$DTDEVROOT/mnt
which resolves by default to
/tmp/SUNWut/(username)/mnt
CDs, DVDs and the like are not yet fully supported, but they might work.
To administer your drives and allow for graceful removal, use the /opt/SUNWut/bin/utdiskadm command.
It kinda seems obvious, but you will loose access to the drive if you hotdesk (i.e. switch from one terminal to the other).
This feature is available since the SSRS 3.0 release.