Library /sys$common/syshlp/bkm$help.hlb E-inv-dev-spec  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Invalid device name.  Enter a device name (such as, DKB0:).

    Meaning:  You entered a device name that is not a valid device name.

    Action:   Reenter a valid device name.  Press PF3 to display a box of
              known disk devices.  Use the arrow keys to scroll through
              the selection options, and press Return to select a device.
              Selecting a device from this box places the selection in
              the name field.

              If you do not want to select a disk device press PF3 again
              (or Ctrl/Z) to cancel the box.