Drivers and Motor Carriers Am I Subject to the ELD Rule? Some devices operate as stand-alone units, some have the capability to connect to a system where you can monitor and supervise a large fleet of vehicles. If you have one or two vehicles, you could consider purchasing a stand-alone unit—just be sure it supports all the minimum. But if i loaded two drivers for a device with same major no and different minor no,and if only one driver is being used for the device,how can I find which driver is used for that device? – Deepu Jun 27 '12 at 6:34.

-->

Non-HID keyboards and mice can connect over multiple legacy buses but still use the same class driver. This section contains details on the class drivers themselves. The following sections goes into details on the controllers.

This topic describes the typical physical configuration of keyboard and mouse devices in Microsoft Windows 2000 and later.

The following figures show two common configurations that employ a single keyboard and a single mouse.

Ruling Input Devices Driver License Test

The figure on the left shows a keyboard and a mouse connected to a system bus through independent controllers. A typical configuration consists of a PS/2-style keyboard operated through an i8042 controller, and a serial-style mouse operated through a serial port controller.

The following additional information is important for keyboard and mice manufactures:

Keyboards are opened in exclusive mode by the operating system stack for security reasons
Windows supports the simultaneous connection of more than one keyboard and mouse device.
Windows does not support independent access by a client to each device.

Class driver features

This topic describes the features of the following Microsoft Windows 2000 and later system class drivers:

Nec modems driver download for windows xp. Kbdclass, the class driver for devices of GUID_CLASS_KEYBOARD device class
Mouclass, the class driver for devices of GUID_CLASS_MOUSE device class

Kbdclass implements the Kbdclass service and its executable image is kbdclass.sys.

Mouclass implements the Mouclass service and its executable image is mouclass.sys.

Kbdclass and Mouclass each feature:

Generic and hardware-independent operation of the device class.
Plug and Play, power management, and Windows Management Instrumentation (WMI).
Operation of legacy devices.
Simultaneous operation of more than one device.
Connection of a class service callback routine that a function driver uses to transfer data from the input data buffer of the device to the data buffer of the class driver.

Configuration of device objects

The following figure shows the configuration of device objects for a Plug and Play PS/2-style keyboard and mouse device. Each class driver creates an upper-level class filter device object (filter DO) that is attached to a function device object (FDO) through an optional upper-level device filter DO. An upper-level device filter driver creates the upper-level device filter DO. I8042prt creates the function DO and attaches it to a physical device object (PDO) created by the root bus driver.

PS/2 Keyboard

The keyboard driver stack consists of the following.

Kbdclass, the upper-level keyboard class filter driver
One or more optional upper-level keyboard filter driver
I8042prt, the function driver

PS/2 Mouse

The mouse driver stack consists of the following.

Mouclass, the upper-level mouse class filter driver
One or more optional upper-level mouse filter driver
I8042prt, the function driver

Kbdclass and Mouclass can support more than one device in two different modes. In the one-to-one mode, each device has an independent device stack. The class driver creates and attaches an independent class DO to each device stack. Each device stack has its own control state and input buffer. The Microsoft Win32 subsystem accesses input from each device through a unique file object.

In the grandmaster mode, the class driver operates all the devices in the following way:

The class driver creates both a grandmaster class DO that represents all of the devices and a subordinate class DO for each device.
The class driver attaches a subordinate class DO to each device stack. Below the subordinate class DO, the device stack is same as that created in the one-to-one mode.
The grandmaster class DO controls the operation of all the subordinate DOs.
The Win32 subsystem accesses all device input through the file object that represents the grandmaster class device.
All device input is buffered in the grandmaster's data queue.
The grandmaster maintains a single global device state.

Kbdclass and Mouclass operate in the one-to-one mode if their registry entry value ConnectMultiplePorts is set to 0x00 (under the key HKLMServicesCurrentControlSet<class service>Parameters, where class service is Kbdclass or Mouclass). Otherwise Kbdclass and Mouclass operate in grandmaster mode.

Open and close via the class driver

The Microsoft Win32 subsystem opens all keyboard and mouse devices for its exclusive use. For each device class, the Win32 subsystem treats input from all the devices as if the input came from a single input device. An application cannot request to receive input from only one particular device.

The Win32 subsystem dynamically opens Plug and Play input devices after it receives notification from the Plug and Play manager that a GUID_CLASS_KEYBOARD or GUID_CLASS_MOUSE device interface is enabled. The Win32 subsystem closes Plug and Play devices after it receives notification that an opened interface is disabled. The Win32 subsystem also opens legacy devices by name (for example, 'DeviceKeyboardLegacyClass0'). Note that once the Win32 subsystem successfully opens a legacy device, it cannot determine if the device is later physically removed.

After Kbdclass and Mouclass receive a create request they do the following for Plug and Play and legacy operation:

Plug and Play Operation
If the device is in the Plug and Play started state, the class driver sends the IRP_MJ_CREATE request down the driver stack. Otherwise the class driver completes the request without sending the request down the driver stack. The class driver sets the trusted file that has read access to the device. If there is a grandmaster device, the class driver sends a create request to all the ports that are associated with the subordinate class devices.
Legacy Operation
The class driver sends an internal device control request to the port driver to enable the device.

Connect a service callback to a device

The class drivers must connect their class service to a device before the device can be opened. The class drivers connect their class service after they attach a class DO to a device stack. The function driver uses the class service callback to transfer input data from a device to the class data queue for the device. The function driver's ISR dispatch completion routine for a device calls the class service callback. Kbdclass provides the class service callback KeyboardClassServiceCallback, and Mouclass provides the class service callback MouseClassServiceCallback.

A vendor can modify the operation of a class service callback by installing an upper-level filter driver for a device. The sample keyboard filter driver Kbfiltr defines the KbFilter_ServiceCallback callback, and the sample mouse filter driver Moufiltr defines the MouFilter_ServiceCallback callback. The sample filter service callbacks can be configured to modify the input data that is transferred from the port input buffer for a device to the class data queue. For example, the filter service callback can delete, transform, or insert data.

The class and filter service callbacks are connected in the following way:

The class driver sends an internal device connect request down the device stack (IOCTL_INTERNAL_KEYBOARD_CONNECT or IOCTL_INTERNAL_MOUSE_CONNECT). The class connect data is specified by a CONNECT_DATA structure that