Drivers & device stacks
Function, filter, bus, class, and miniport drivers in layered request handling.
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I/O & drivers
From I/O Manager and IRPs through driver stacks and PnP power.
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Why it matters
Most real device interactions involve layered drivers. Seeing the stack explains why debugging I/O often means following a request across several components.
Mental model
A device stack is a pipeline of specialists. Each driver adds, inspects, or refines part of the work.
Go one level deeper
Extra detail for readers who want more precision before opening a child topic.
- Filter drivers can sit above or below class drivers (upper/lower filters).
- WDM and KMDF are frameworks; the IRP model is the common contract.
How it works
- 1Bus drivers enumerate hardware and expose child devices.
- 2Function/class drivers implement the main device behavior.
- 3Filter drivers observe or modify requests before they continue.
Key terms
- Filter driver
- A driver that inspects or changes I/O passing through a stack.
- Bus driver
- A driver responsible for enumeration and management of devices on a bus.
A storage request through layered drivers
The request may travel from a file system to a volume driver, then a disk class driver, a port driver, and finally a miniport driver.
Common misconception
Not every driver talks to hardware directly; many only cooperate inside the stack.
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