*TUBE       - error
*TUBE ON    - enables Tube immediately until Break
*TUBE OFF   - disable Tube immediately until Break
*TUBE <num> - selects CPU to use after next Break

Can't configure Tube ON/OFF via transient as needs to hook into
service call 1.

*TUBE OFF needs to turn EVENTV off as it will still be pointing
to Tube Host.

Need thoughts on ROM *TUBE command semantics. *TUBE ON|OFF
takes immediate temporary effect, what syntax to select
permanant effect?

*CONFIGURE NOTUBE - disables Tube after next Break
*CONFIGURE TUBE   - enables Tube after next Break
*TUBE OFF         - disables Tube immediately until next Break
*TUBE ON          - enables Tube immediately until next Break
   ???            - disables Tube immediately and after next Break
   ???            - enables Tube immediately and after next Break

*TUBE ENABLE
*TUBE DISABLE

*TUBE <cr>        - display information?
                  - so, make transient *TUBE <cr> not a syntax error.


  TUBE  (ON|OFF|ENABLE|DISABLE|<num>)

*TUBE OFF - stop now
*TUBE DISABLE - stop after Break
*TUBE OFF DISABLE - stop now and after Break

*TUBE ON - start now
*TUBE ENABLE - start after Break
*TUBE ON ENABLE - start now and after Break


*CONFIGURE (NO)OPTION counterpart to *OPTION (EN|DIS)ABLE
eg:
*CONFIGURE TUBE <-> *TUBE ENABLE

*TUBE    (ON|OFF|ENABLE|DISABLE) - ON/OFF doesn't persist, ENABLE/DISABLE persists
*EXPLODE (ON|OFF) - persists
*MIDI    (ON|OFF) - doesn't persist
*LCD     (ON|OFF) - doesn't persist
*SERLINK (ON|OFF) - persists
*MOUSE   (ON|OFF) - doesn't persist


ReselectFS doesn't reselect TAPE or ROMFS as they don't respond to service
calls.