page_type	sample
description	A tool to monitor and log any I/O and transaction activity that occurs in the system.
languages	cpp
products	windows windows-wdk

Minispy File System Minifilter Driver

The Minispy sample is a tool to monitor and log any I/O and transaction activity that occurs in the system. Minispy is implemented as a minifilter.

Universal Windows Driver Compliant

This sample builds a Universal Windows Driver. It uses only APIs and DDIs that are included in OneCoreUAP.

Design and Operation

Minispy consists of both user-mode and kernel-mode components. The kernel-mode component registers callback functions that correspond to various I/O and transaction operations with the filter manager. These callback functions help Minispy record any I/O and transaction activity occurring in the system. When a user can request the recorded information, the recorded information is passed to the user-mode component, which can either output it on screen or log it to a file on disk.

To observe I/O activity on a device, you must explicitly attach Minispy to that device by using the Minispy user-mode component. Similarly, you can request Minispy to stop logging data for a particular device.

For more information on file system minifilter design, start with the File System Minifilter Drivers section in the Installable File Systems Design Guide.