Handling IRPs: Introduction

Introduction

The Microsoft® Windows® family of operating systems communicates with drivers by sending I/O request packets (IRPs). The data structure that encapsulates the IRP not only describes an I/O request but also maintains information about the status of the request as it passes through the drivers that handle it. Because the data structure serves two purposes, an IRP can be defined as: 

·         a container for an I/O request

– or –

·         a thread-independent call stack

 

Considering IRPs from these two perspectives may help driver writers understand what their drivers must do to respond correctly to I/O requests.

For current documentation on routines and issues discussed in this paper, see the most recent version of the Microsoft Windows Driver Kit (WDK).