HP Brio ba200 hp desktop pcs, plug and play for Microsoft Windows 2000 (Micros - Page 12

device from which other devices are enumerated is referred to as

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Windows 2000 White Paper 8 Upper-level filter drivers usually provide added-value features for a device. For example, an upper-level device filter driver for a keyboard could enforce additional security checks. 9…v‰r…ÃGh’r…† For a given device, there are two or more driver layers: a bus driver for the underlying I/O bus (or the Plug and Play Manager for root-enumerated devices) and a function driver for the device. Optionally, one or more filter drivers can be provided for the bus or device. 9r‰vprÃPiwrp‡† A driver creates a device object for each device that it controls; the device object represents the device to the driver. From the Plug and Play perspective, there are three kinds of device objects: physical device objects (PDOs), functional device objects (FDOs), and filter device objects. PDOs represent a device on a bus; every Plug and Play API that refers to a device refers to the PDO. FDOs represent the functionality of a device to a function driver. Filter device objects represent a filter driver as a hook to add value. These three kinds of device objects are all of the type DEVICE_OBJECT, but are used differently and can have different device extensions. 6qqv‡v‚hyÃXvq‚†ÃD‡r…shpr† Windows 2000 Plug and Play drivers are not limited to using the WDM interfaces. Drivers can call other interfaces to support legacy Windows NT drivers, detection, or other Windows-specific capabilities that are not provided under WDM. Notice that a driver that supports features specific to Windows NT is no longer compatible with Windows 98. If a driver will be used under both Windows NT and Windows 98, only WDM interfaces can be used. X9HÃ7ˆ†Ã9…v‰r…† Bus power management and Plug and Play are controlled by WDM bus drivers, which are standard WDM drivers that expose bus capabilities. In this context, any device from which other devices are enumerated is referred to as a bus. A bus driver responds to new Plug and Play and power management I/O request packets (IRPs) and can be extended using filter drivers. The bus driver is primarily responsible for the following: • Enumerating the devices on its bus. • Reporting dynamic events on its bus to the operating system. • Responding to Plug and Play and power management IRPs. • Multiplexing access to the bus (for some buses). • Generically administering the devices on its bus. During enumeration, a bus driver identifies the devices on its bus and creates device objects for them. The method that a bus driver uses to identify connected devices depends on the particular bus.

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Windows 2000 White Paper
8
Upper-level filter drivers usually provide added-value features for a device. For
example, an upper-level device filter driver for a keyboard could enforce
additional security checks.
For a given device, there are two or more driver layers: a bus driver for the
underlying I/O bus (or the Plug and Play Manager for root-enumerated devices) and
a function driver for the device. Optionally, one or more filter drivers can be provided
for the bus or device.
A driver creates a device object for each device that it controls; the device object
represents the device to the driver. From the Plug and Play perspective, there are
three kinds of device objects: physical device objects (PDOs), functional device
objects (FDOs), and filter device objects. PDOs represent a device on a bus; every
Plug and Play API that refers to a device refers to the PDO. FDOs represent the
functionality of a device to a function driver. Filter device objects represent a filter
driver as a hook to add value. These three kinds of device objects are all of the type
DEVICE_OBJECT, but are used differently and can have different device
extensions.
Windows 2000 Plug and Play drivers are not limited to using the WDM interfaces.
Drivers can call other interfaces to support legacy Windows NT drivers, detection, or
other Windows-specific capabilities that are not provided under WDM.
Notice that a driver that supports features specific to Windows NT is no longer
compatible with Windows 98. If a driver will be used under both Windows NT and
Windows 98, only WDM interfaces can be used.
Bus power management and Plug and Play are controlled by WDM bus drivers,
which are standard WDM drivers that expose bus capabilities. In this context, any
device from which other devices are enumerated is referred to as a
bus
. A bus
driver responds to new Plug and Play and power management I/O request packets
(IRPs) and can be extended using filter drivers.
The bus driver is primarily responsible for the following:
•
Enumerating the devices on its bus.
•
Reporting dynamic events on its bus to the operating system.
•
Responding to Plug and Play and power management IRPs.
•
Multiplexing access to the bus (for some buses).
•
Generically administering the devices on its bus.
During enumeration, a bus driver identifies the devices on its bus and creates
device objects for them. The method that a bus driver uses to identify connected
devices depends on the particular bus.