Devices and buses are grouped as classes in Windows 95, for purposes of installing and managing device drivers and allocating resources. The Registry contains a subkey for every class of device supported, and the hardware tree (as described in the following section) is organized by device class. Windows 95 uses class installers to install drivers for all hardware classes. Device Manager, for example, sends messages to the various class installers to tell them to add, remove, or configure specific hardware.
The following are some examples of class names defined in Windows 95:
Adapter Cdrom Display EISAdevices FDC HDC | Keyboard MCADevices Media Modem Monitor | Mouse MTD Net NetService Nodriver | PCMCIA Ports Printer SCSIAdapter System |
The Windows 95 hardware tree is a record of the current system configuration, based on the configuration information for all devices in the hardware branch of the Registry. The hardware tree is created in RAM each time the system is started or whenever a dynamic change occurs to the system configuration.
Each branch in the tree defines a device node with the following requirements for configuration:
Most information in the Windows 95 hardware tree can be seen by using Device Manager, which you can display by choosing the System option in Control Panel. Device Manager is described in Chapter 19, "Devices."
You can also see the information in the hardware tree in the Hkey_Dyn_Data\Dynamic\Enum section of the Windows 95 Registry.
The configuration process in Windows 95 uses the device nodes to identify the devices and resource requirements for establishing the working system configuration. For information about the components that work together in Windows 95 to configure the system, see Chapter 31, "Windows 95 Architecture."