Windows Support Menu
Windows 9X Devices
Overview – Multiple Display Support
Windows 98 now supports both multiple video cards and video cards that have multiple outputs. This increases the usable desktop area and allows customers to keep applications open on different screens or expand them across multiple screens.
If you have a PCI computer with two or more PCI display adapters and monitors, you can take advantage of Multiple Display Support. You can, for example, click an HTTP link while you read e-mail and have the browser start on an adjacent monitor. Or you can play a game using different monitors for left, right, and center perspectives or as separate instrumentation consoles. Multiple display support can also be used for desktop publishing, presentations with notes, or as a way to expand the desktop.
Configurations have been successfully tested up to nine monitors (such as a 3 x 3 grid), although two or three are normally encountered.
Multiple Display Support is a set of related features that support the use of more than one display device at a time. Additional application programming interfaces and device driver interfaces are provided under Microsoft DirectX version 5.0.
The user interface has been modified to recognize a desktop that spans multiple monitors, with no restrictions on size or position. For monitors attached to the same system but showing different images simultaneously, the different displays may have differing (x,y) resolution and refresh rates, as well as differing display capabilities.
To support this capability, new APIs in the Win32 API set enable any application to take advantage of multiple monitors. Applications do not need to be modified to work on a computer with multiple monitors, but application developers can take special advantage of this feature by calling the new APIs.
In troubleshooting On-Now and ACPI, first thing to ask the customer is "Does the machine support the ACPI specification?" ACPI requires changes in both the BIOS and the chipset on the motherboard for full implementation.
Multiple Display Support uses the concept of primary and secondary displays. The hardware requirements for the two display types are the same. Both video display adapters must be PCI or AGP devices. The ability to change these types of device’s resources is what allows Windows 98 to work with two display adapters.
With Multiple Display Support, the operating system still needs a PCI VGA device, which becomes the primary display. The system BIOS picks the primary VGA device based on the PCI slot order — unless the BIOS offers an option for picking which device is to be treated as the VGA device. The VGA device cannot be stopped, which is an important consideration for docking units, such as the CP family with the C/Dock Expansion Replicator.
Note: Some laptops when "Hot docked" into a docking station that contains a display adapter will disable, or turn off, the laptop’s built in display. With the CP family and the C/Dock, using A04 for the CP or A00 for the Cpi, this feature is not an issue. The BIOS has been written to allow for the C/Dock PCI card to be primary and the Neomagic video to be secondary.
AGP (Accelerated Graphics Port) is a specification from Intel that boosts the performance and quality of accelerated 3-D graphics. AGP is a local bus that directly connects your graphics hardware to the CPU and system memory. This bypasses the PCI bus.
AGP graphics cards plug into an AGP slot. Graphics running through the AGP bus move about four times faster than a PCI bus graphics card. Microsoft is supporting AGP in DirectX 5.0 APIs. 3-D software gets the biggest benefit since programs can use the main system memory to store the 3-D graphics.
AGP graphics cards connect directly to the system chipset over a 64-bit AGP bus. The bus runs at 66 MHz, and is designed to handle two transactions per clock cycle. If your system has both, a PCI and AGP card, the PCI card will generally be seen first and acts as the primary display card but is dependant upon how the system will initialize the video subsystem.
These cards cannot be used in Multiple Display Support:
Primary and Secondary Display
The primary and secondary display, and all display adapters thereafter must be one of the following chipsets and use a DirectX 5.0, Multiple Display Support enabled, display driver (included in Windows 98):
These drivers have DirectDraw support:
This driver has Direct3D support:
Note: The list above are supported chipsets not display adapters. There are currently several display adapters that use the S3 ViRGE chip and all are Multiple Display Support capable with the appropriate display driver.
Customers can freely mix and match display hardware because the graphics adapters do not need to be identical. Each display device and monitor combination is separately enumerated and configured and can have completely different screen characteristics. This means that each monitor can have different resolutions and color depths. For example the primary display might be set for 1024x768x256 while the secondary is set to use 800x600x32K
Enabling Multiple Display Support
Multiple Display Support requires that all of the display adapters be PCI or AGP devices. The setup instructions vary according to the following two scenarios:
Onboard display chipset and display adapter
Follow these instructions when your motherboard has a PCI or AGP display chipset and you have a second PCI or AGP display adapter to plug in.
If your computer has built-in display chipset on the motherboard, follow these steps exactly when setting up Windows 98:
Two separate plug-in display adapters
If all the display adapters you want to put in your computer are on add-in cards (that is, none of the display adapters in the system are on the motherboard or built in), you can install all of them before setting up Windows 98.
If your computer has two plug-in PCI display adapters follow these steps exactly when setting up Windows 98:
Multiple Display Support Configuration
When implemented in a PC system, Multiple Display Support can be configured as multiple monitors, each connected to its own graphics adapter, or as multiple monitors connected to a single adapter that supports multiple outputs. Under either configuration, each display device can have different sizes or positions, and each device can use a different color depth.
Increasing Screen Real Estate
Multiple Display Support uses the concept of a virtual screen, where each monitor displays a piece of the larger virtual screen. The upper left corner of the primary display is considered X, Y point 0,0. This means that in the configuration shown above, any application that is being displayed on Display2 is being run in negative space. Negative space is where the X, Y coordinates are less than zero. This may cause some application compatibility issues.
The most common scenario is shown below using two screens with the secondary display extending the desktop to the left.
Tip: When troubleshooting application issues, try running the application in the primary display. Also test with the applets that come with Windows 98 (i.e. Paint, Wordpad…)
To change the order of the monitors go to the Control Panel – Display – Settings tab. The size of the monitor on the screen will give an indication of the resolution that the adapter is using. The larger the screen, the higher the resolution. In the example below you can see that monitor one is running at 1024x768 while monitor two is running at a lower resolution. To see the resolution click the Display drop down list box and select the second display.
The picture of the monitors above is a virtual layout of the display. You do not have to physically move the monitors to match the layout above.
Clicking and dragging the picture of the monitor to its desired location will change the monitor positioning on the virtual desktop. Given the example above this configuration will allow a mouse pointer dragged off the left side of Display 1 to appear on the right side of Display 2. This will allow the virtual desktop to be configured to match the physical layout of the monitors.
Clicking the "Advanced" button allows the customer to choose the specific display adapter’s settings (adapter and monitor settings, as well as performance and color management).
The positions of the screens in the control panel dictate the relative positions of the screens to each other. If one screen is located above the other, then the mouse pointer must be moved up or down to reach the other screen.