1# HDF Overview<a name="EN-US_TOPIC_0000001051611604"></a> 2 3- [Introduction](#section0649162112376) 4- [Driver Loading](#section68701942154319) 5- [Driver Service Management](#section12453133414412) 6- [Driver Message Mechanism](#section129410710451) 7 8## Introduction<a name="section0649162112376"></a> 9 10The Hardware Driver Foundation \(HDF\) provides the following driver framework capabilities: driver loading, driver service management, and driver message mechanism. This unified driver architecture platform is designed to provide a more precise and efficient development environment, where you can perform one-time development and multi-system deployment. 11 12## Driver Loading<a name="section68701942154319"></a> 13 14Both on-demand loading and sequential loading are supported. 15 16- On-demand loading 17 18 Drivers can be loaded by default during the operating system \(OS\) startup or be loaded dynamically after the OS startup. 19 20- Sequential loading 21 22 Drivers can be loaded based on their priorities during the OS startup. 23 24 25## Driver Service Management<a name="section12453133414412"></a> 26 27The HDF centrally manages driver services. You can directly obtain a specified driver service by using the API provided by the HDF. 28 29## Driver Message Mechanism<a name="section129410710451"></a> 30 31The HDF provides a unified driver message mechanism, which allows message interactions between user-level applications and kernel-level drivers. 32 33