This section defines the PC 98 requirements for ensuring system support for multiple adapters and multiple monitors. This support ensures that if the user adds a second adapter, resources will automatically be available and the operating system can automatically manage multiple display adapters.
The actual implementation a user might employ could be one of the following:
The support planned for both Windows and Windows NT requires multiple-adapter compatibility in both the graphics adapter and its driver. With this new multiple-adapter/multiple-monitor support, a single adapter that supports multiple monitors can display independent screen images. This support is beyond the current simultaneous display features of some mobile PCs, which simultaneously show the same Windows desktop on two monitors.
The operating-system support for multiple adapters and multiple monitors requires allowing any secondary graphics adapters to be enabled in VGA mode, thus requiring that VGA for the previous adapter be temporarily disabled.
The support for multiple monitors also assumes that for monitors attached to the same system, but showing different images simultaneously, the different displays might have differing X,Y resolutions, color depths, refresh rates, and display capabilities.
For technical details about implementing driver support for multiple adapters and multiple monitors, see the Windows NT 5.0 DDK.
17. Extended resources can be dynamically relocated after system boot
| Required |
To ensure Plug and Play for multiple-adapter/multiple-monitor capabilities, all non-VGA standard display resources (also known as extended resources, such as register sets and so on) must be capable of being dynamically relocated after system boot.
This is an extension of the “Graphics operations use relocatable registers only” requirement earlier in this chapter. It also is an addition to the “General Plug and Play Requirements” section later in this chapter.
18. VGA resources can be disabled by software
Required
A means must be provided to allow a driver to disable its adapter from decoding standard VGA addresses. The purpose of this is to ensure that the adapter is independent of all other graphics adapters in the system. The adapter must remain fully functional without the VGA addresses. See also the “Graphics operations use relocatable registers only” requirement earlier in this chapter.