HP Brio ba200 hp desktop pcs, plug and play for Microsoft Windows 2000 (Micros - Page 14

QGVBÃ6I9ÃQG6`Ã9@WD8@ US@@ The Plug and Play Manager maintains a device tree, viewable through Device Manager, which keeps track of the active devices in the system and information about those devices. The Plug and Play Manager updates the device tree as devices are added and removed or as resources are reallocated. The device tree is hierarchical, with devices on a bus represented as children of the bus adapter or controller. The registry is the central repository for static hardware information. Plug and Play system components and drivers build, maintain, and access new and existing subtrees in the registry . During enumeration, data for each device is stored under a new HKEY_LOCAL_MACHINE\System\CurrentControlSet\Enum key in the registry (this is the enum tree). Plug and Play makes decisions about which device drivers are loaded based on the results of enumeration. Thus, there is an important connection between the enum tree and the services list in HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services. Figure 2 shows a Plug and Play device tree for a hypothetical ACPI system configuration. In practice, a device tree would consist of many additional devices, but Figure 2 shows only the devices needed in this discussion. Windows 2000 White Paper 10