Conference bulova::decw_jan-89_to_nov-90

    VMS DECwindows and Multi-head Workstations
    ==========================================

    What is a multi-headed workstation?
    -----------------------------------

    A multi-headed workstation consists of one system, one keyboard, one
    mouse and more than one monitor with its graphics controller. It is
    a single user workstation. This is distinguished from a multi-seat 
    workstation which is one system with multiple keyboards, mice, and
    monitors. 

    How does VMS DECwindows handle multi-headed workstations?
    ---------------------------------------------------------

    Starting with VMS V5.3, DECwindows was enhanced to handle multi-
    headed workstations. 

    The X11 server was modified to allow multiple X11 screens to be 
    connected to a single server. The mouse cursor can be moved freely 
    across the screens, and a single keyboard can be used to generate 
    input to windows on any screen. The server implementation handles
    each monitor as a separate X11 screen. This means that a single
    window cannot cross screen boundaries, e.g. you cannot drag a window
    from one monitor to another. However, it does allow the monitors to
    be of different types. For instance, you can mix a monochrome frame
    buffer screen with a GPX or SPX color screen. 

    Although no bundled applications do so, an application can be 
    designed to use both screens.  This can be done with standard X11 
    capabilities.

    To start applications which are designed only to use a single screen
    on screens other than screen zero, you can use the /SCREEN switch on 
    the SET DISPLAY command, e.g. 
    
    	$ SET DISPLAY /CREATE /NODE=FOOBAR /SCREEN=1
    
    The session manager was also enhanced for multi-headed workstations.
    In these configurations, the session manager starts a separate window
    manager on each screen. A new entry appears on the session manager's 
    customize menu called "Screen Number...". This let's you control which
    screen applications are started on, and also let's you control which
    screen the printscreen function applies to. 
   
    Directions for customizing DECwindows to run on multi-headed 
    configurations can be found in the file:

	SYS$MANAGER:DECW$PRIVATE_SERVER_SETUP.TEMPLATE

    Are there any known limitations with the software implementation?
    -----------------------------------------------------------------

    VMS V5.3 handles a maximum of 3 screens; VMS V5.3-1 handles up to 4.
    The device drivers for the MFB, GPX, and SPX graphics controllers do
    not have SMP support, so you cannot do a mix of VS35x0 (Firefox) and 
    anything else if you have SMP enabled. If you have a mixed mono/color 
    system, the color system should be configured as screen zero. Testing
    with more than 2 screens has been limited.

    Additional hints and kinks can be found in the DECWINDOWS notes
    conference on BULOVA in note 282.

    What multi-headed hardware configurations are possible?
    -------------------------------------------------------

    Using Q-bus based VAXstationII or VS3500 & VS3600 systems, you can 
    configure multi-head systems by plugging more than one graphics 
    controller into the Q-bus. For instance, on a VS3600, two head GPX 
    controllers can be configured. There are power and slot restrictions 
    that apply, so you should contact field service for details. Dual
    head VS3500 & VS3600 systems have not been FCC qualified.

    VS3100 and VS2000 systems are busless, however, dual headed mono/color 
    configurations are possible. All VS3100 and VS2000 systems have the 
    monochrome frame buffer logic on the system card. When GPX or SPX 
    controllers are added, the MFB logic remains. A special cable is being 
    produced that will allow both a color and monochrome monitor to be 
    attached to any VS3100/GPX or VS3100/SPX system. This cable is expected 
    to be announced in the Spring of 1990 with an anticipated price of 
    around than $50. Jim PVX:: Kovac is the product manager. Only the
    VS3100 systems will be FCC qualified.

    What does VMS DECwindows officially support?
    --------------------------------------------

    VMS engineering will accept bug reports on multi-headed configurations
    beginning with VMS V5.3-1. 
    

	...and as a use of a multi-head VS3100, I can say that it's the
	greatest thing since sliced bread. I have a VR290 (19" color)
	and a VR262 (19" mono) hooked up. I have the best of both worlds
	now.. A color tube for doing color things and a mono tube for
	comfortable reading of text. If I run an application that
	takes up one whole screen, I still have another for reading mail
	and stuff.

	How easy was it to get used too? Incredibly.

	What else needs to be done? I'd say that the ability to specify
	screens in the Autostart menu. Other than that, it's been working
	great for quite a while.

	BTW, Friday I was playing with Motif. I ran the Motif window manager
	on my color system and the DEC window manager on my mono. No problem.


	BTW, don't come to be for a cable.. I have a pre-proto cable that 
	looks nothing like the one that will be sold.

	For Sales folks, this is a VERY cheap way of getting your customers
	into multi-head configurations.

							mike

    > What else needs to be done? I'd say that the ability to specify
    > screens in the Autostart menu. Other than that, it's been working
    > great for quite a while.
    
    To accomplish this, add "-d :0.n" to your application definitions, where
    n is the screen number where you want your appilcation started.
    

RE: .3

	That works fine if the commands are started up as a foreign command
	but not all are..

								mike

    You might be interested in an example I posted in ELKTRA::DW_EXAMPLES
    note 401, which can allow you to control several (in theory, any
    number) of independent workstations or X-terminals from a single
    keyboard/mouse.  It's a crude hack, totally unsupported, and has many
    limitations (e.g. can't use standard window managers), but may be worth
    a look since it requires  no special hardware support, and could
    control non-Digital workstations if necessary.
    
    -- Rob

  We needed a two-headed configuration to allow us to do some troubleshooting.
Since you can't buy the *real* cable yet, I got out the prints and figured out
the pinouts.

  My "cable" is really an adaptor that is about 6" long with a 6 foot cable
hanging off that connects to the monochrome monitor.  It allows me to 
connect a monochrome monitor to a 2000 GPX or 3100 GPX.  You still will use
the cable you already have to connect the color monitor/keyboard/mouse.

  There is no "trick" to the cable.  What it does is pull the monochrome video
signals out, and passes the color video, keyboard, and mouse signals along. 
One end of the adaptor cable connects to the workstation, and the other end 
connects to the BC19S color video/mouse/keyboard cable.

  The cable is simple to build.  Get male and female 15 pin connectors, (you
might be able to get them from your local network people, they are the same
15 pin connectors used to connect to ethernet transceivers) and wire all 15
pins straight thru except for 3 and 9.  Use a piece of thin ethernet cable
for the monochrome video.  Wire the center conductor to pin 9 and the shield
to pin 3.  Be sure to wire the mono video signal to the *workstation* side of
the adaptor.

  Be careful to not to cross any pins.  It is possible to blow up your 
workstation, mouse, or keyboard.  If you do, don't say I didn't warn you! B-)

Jeff.

but I couldn't post it in this conference because the notes server was too
old.  The next will be a retry of that posting.

I should add that I've since ECO'd this design to cut down on the interference
between the B/W and RGB signals, but as usual I haven't updated the engineering
drawing, but what do you expect from a software engineer. :)

    I heard today that the official cable adpater will be shipping
    in july.
    
    Jeff
    

    I am quite successfully running a VS3100 with two screens. However,
    although I started to use the cabling as show a bit before, my
    soldering skills made that after some movements and so on, a short
    circuit happened, and disjoncted the VS. Pretty impressive.
    Therefore, while waiting for the official cable that I will buy, no
    doubt about it, I decided to make something a bit more accurate, and
    used these flat wide cables with 15 wires, and a serie of connectors (2
    males, one female) that you just have to squeeze on the cable.
    Then, I just had to connect  a color cable, and a monochrome cable,
    each of these picking the signals it is interested by. 
    Result is fine, except some 'noise' on certain background patterns,
    probably due to the lack of isolation.
    
    Pierre.

The cable number from the new Systems and Option Catalogue is

   BC09E-06	Dual Monitor adapter, Includes a 6 foot monochrome cable