
            Documentation for Enabling and Using Multihead on 
            Compaq Optimized Windows NT Driver for
            ELSA GLoria Synergy Graphics Options.

			      Version 2.0e
			      04-Jan-1999



The Compaq Optimized Windows NT Driver for ELSA GLoria Synergy supports
the Alpha based platforms Compaq Professional Workstation XP1000 and
Digital Personal Workstation 433a, 500a and 600a enhanced.  This
document describes the supported Multihead configurations on Alpha
Platforms and how to enable Multihead.

Please read the entire document before planning to use the Compaq
Optimized ELSA GLoria Synergy driver in a Multihead configuration. 


1.0 What is Multihead ?

The Windows NT 4.0 graphics interface, GDI, does not handle the use of
multiple graphics boards. It is left as a task for the display drivers
to adapt a customized setup that creates a virtual window spanning
multiple screens, with each screen connected to its own graphics board.
This is commonly known as Multihead (also known as Multimonitor).

The Compaq Optimized ELSA GLoria Synergy driver contains the necessary
code to support Multihead configurations.  The driver can accelerate GDI
calls (2D Multihead) in Multihead configurations. In the current
implementation, only Homogeneous Multihead is supported.  Homogeneous
Multihead refers to support of configurations containing identical
devices.  For example, Multihead will function correctly in a system
containing multiple 8MB ELSA GLoria Synergy's, however, it will not
function correctly in a system containing a mixture of 4MB or 8MB
PowerStorm 4D10T and ELSA GLoria Synergy boards.


2.0 Supported Configurations for 2D Multihead

The Digital Personal Workstation Series and the Compaq XP1000 line of
systems that use ELSA GLoria Synergy can support 2D Multihead, up to
three 8MB ELSA GLoria Synergy's can be installed on the same system.


3.0 How to enable 2D Multihead

This section assumes that you have a working system with one ELSA GLoria
Synergy. To enable Multihead:

- Shut the system down and turn the power off.
- Disable VGA on all the ELSA GLoria Synergy cards except the one which
  will be the VGA console.  The Multihead system should contain only one
  ELSA GLoria Synergy card with VGA enabled.  Note:  To disable VGA, set
  the switch on the ELSA GLoria Synergy to the ON position.  To enable
  VGA, set the switch on the ELSA GLoria Synergy to the OFF position.
- Plug in all the cards into the system.  Connect the monitors to all
  the cards.
- Power on the system. Power on the monitors.

The monitor connected to ELSA GLoria Synergy with VGA enabled will
display the boot process.  It is very likely that once the system
completes the boot procedure and enters Graphics mode, the login box
will be on a different monitor. It is very important to power on all
the monitors and make sure they are connected to their respective cards
properly.

After login, go to Display Properties (either by right-clicking your
mouse on the desktop or from the Control Panel).  Select settings and
modify the resolution.  You will be able to select resolutions that span
multiple screens.  Select a suitable resolution for your system
configuration and apply the change after testing it.  At this point,
the different monitors should reveal parts of a large Desktop.  You
should be able to run 2D applications, move them from one screen to
another and maximize the application windows to cover all the different
monitors. 

If after login, you are not able to modify the resolution to cover
multiple monitors, please check the following:

- Are all the ELSA GLoria Synergy's plugged in properly ?
- Is VGA disabled on all but one ELSA GLoria Synergy's ?
- Did you select a resolution that will enable all your
  boards? To enable 3 boards, you must pick a resolution
  that's three times that of a single screen, for example
  [3072 by 768] for 3 * [1024 by 768].

4.0 3D HW Acceleration in Multihead Configurations

3D is supported only in single head configurations.


Copyright (c) 1999 Compaq Computer Corporation
