Currently there is no “button” to eject or load virtual CD media. However, you can eject/load the media issuing a command from OpenVMS or Tru64 (see the subsections below).
Currently you cannot specify another CD image name on the fly. However, you can put another image in the file with the same name and mount it again. The virtual medium is loaded automatically, if the file is present.
On OpenVMS.
you can use the RZT tools for it. First define the symbol:
$ rzt:==$sys$etc:rztools_alpha
Unload the CD:
$ rzt dka400 /stop
Load the CD:
rzt dka400 /start
On Tru64/Digital UNIX.
You can eject the CD as follows:
scu -f /dev/rdisk/cdrom0c eject