The Design Guide is subdivided into sections; with each section corresponding to a hardware device or adapter class. Most users of the Microsoft® Windows® 95 Device Driver Kit (DDK) are interested in just one, or at most two, of these sections and can ignore the others. For example, when device driver engineers use the DDK, they are usually building a driver for one specific device or adapter class and are only interested in that section in the guide. For example, an engineer developing a driver for a display adapter is only interested in the Display Drivers section of the guide.
Topics of interest to device driver developers for all classes of devices, such as Plug and Play and device installation, are in the Programmer's Guide.
Sections in the Design Guide correspond roughly to the Windows Hardware Quality Labs (WHQL) hardware categories. The WHQL hardware categories are changing and evolving as more and more certification tests are developed by WHQL. One goal for the guide is to make it clear which WHQL certification tests apply to a device or adapter driver developed with the help of a particular section of the guide.
The following table shows the relationship between the sections of the Driver Design Guide and the WHQL hardware categories.
| WHQL hardware category | Design Guide section |
|---|---|
| Audio adapters | Multimedia |
| Display adapters and monitors | Display |
| Input devices | Multimedia (joystick), Keyboard, Mouse, and Pen |
| Modems | Modems |
| Network adapters | Networks and Infrared |
| Printers | Printers |
| Storage adapters and devices | Storage |
| Computer Systems | Communications |
| Video capture adapters | Multimedia |
The Communications section covers writing drivers for serial (COM) and parallel (LPT) ports; the WHQL Computer Systems hardware category includes entire platforms, not just the serial and parallel ports. WHQL has a hardware category called Microprocessors (mother boards); there is no comparable section in the Design Guide.
The catch-all Multimedia section may disappear in the future, both as a WHQL device class category and a DDK Design Guide section, as WHQL develops certification tests for display, audio, joystick, and modem devices that use hardware designs recommended for running DirectX software.