Queues and Other Support Objects

After the driver creates and initializes the device object, the driver creates additional objects that are associated with the device object. These additional objects provide services that the driver uses to control the device and handle I/O requests. Along with the device objects, they form the working structure of the driver.

Table 6-3 lists the additional objects that drivers most commonly create. Each of the objects in the table is typically a descendant of a device object.

Table 6-3: Common Objects
Open table as spreadsheet

Object	Description	Supporting framework
I/O queue object	Manages the flow of I/O requests to the driver.	UMDF and KMDF See Chapter 8, "I/O Flow and Dispatching"
I/O target object	Represents a target for I/O requests.	UMDF and KMDF See Chapter 9, "I/O Targets"
USB device, interface, and pipe objects	Represent a USB device and describe a USB configuration and the endpoints in a configuration.	UMDF and KMDF See Chapter 9, "I/O Targets"
Interrupt object	Represents an interrupt vector or interrupt message.	KMDF See Chapter 16, "Hardware Resources and Interrupts"
Lock object	Provides serialization for shared resources.	KMDF See Chapter 10, "Synchronization"
WMI provider and instance objects	Provide WMI features so that the driver can export information to other components.	KMDF See Chapter 12, "WDF Support Objects"
DMA enabler, transaction, and common buffer objects	Enable the use of the framework's DMA support and describe a DMA transaction and buffer.	KMDF See Chapter 17, "Direct Memory Access"

This chapter indicates where your driver should create and initialize these objects, but does not provide detailed explanations of what they do and how they work.