What Does Windows Driver Model Mean?

If you are looking for the meaning of WDM or Windows driver model, then know everything there is related to the model right in this blog.

The Windows Driver Model, often known as WDM, is an architecture or framework for drivers that ensures that source code runs on Windows Me, Windows 98, Windows XP, and every subsequent version of Microsoft Windows. This only includes the 32-bit Windows. The “VxD” driver technology that was used on earlier versions of Windows, like Windows NT, Windows 3.1, and Windows 95, was intended to be replaced by such driver technology.

You may already know that executing a Windows driver update can enhance your PC’s performance and speed, the task of this driver model is quite similar as well. The Windows Driver Model is a layer that was added to the intermediate layer of the kernel-mode drivers in Windows 2000. Its purpose was to improve the efficiency and usefulness of the process of creating drivers for Windows. This may not always be desirable, and specialized drivers may be built for each operating system, despite the fact that this was primarily meant to be binary- and source-compatible across Windows 98 and Windows 200.

The Windows Driver Model is not typically backward-compatible. This means that it is not guaranteed that such a driver will operate on any previous version of Windows. For instance, Windows XP is able to utilize a driver that was developed for Windows 2000, but it is unable to use any of the additional capabilities that were included in Windows XP. On the other hand, a driver that was designed for Windows XP may not load at all on Windows 2000.

By adhering to such specifications, drivers have the ability to be binary-compatible and source-compatible across several versions of Windows, including Windows Vista, Windows Server 2003, Windows XP, Windows 2000, Windows Me, Windows 98 2nd Edition, Windows 98, and (for backward compatibility) on x86-based machines.

Know More about the Model in Respect to OS

Such drivers are supposed to be forward-compatible, which means that such a driver may operate on a version of Windows that is newer than the version of Windows that the driver was first created for. However, if this were to occur, the driver would not be able to make use of any new capabilities that were included with the new version of Windows.

I/O request packets, often known as IRPs, are the means through which such drivers interact with one another inside a stack. The Windows Driver Model from Microsoft unified driver models for the Windows NT and Windows 9x product lines. This was accomplished by standardizing requirements and lowering the total amount of code that needed to be developed. Such drivers may not be compatible with operating systems released before Windows 2000 or Windows 98. This includes Windows NT4.0, Windows 3.1, and Windows 95.

The Windows 98 operating systems (Windows 98 2nd Edition, Windows Me, and Windows 98) are compatible with the VxD drivers and such drivers in equal measure. However, in most cases, such drivers provide additional functions, such as a TV tuner card’s capability to collect pictures at a better quality.

Common Complaints of Driver Software Creators Regarding WDM

The following are some of the complaints that driver software creators have voiced in response to the driver:

• There is an absence of technical help available for the process of building “user-mode drivers,” often known as customized special-purpose drivers.
• There are hundreds of lines of support code necessary for every driver.
• Canceling (input/output) instructions presents a significant number of challenges.
• It may be challenging to navigate the interconnections between power management events and plug-and-play.
• The fact that it is really difficult to comprehend.

There is some uncertainty over the quality of both the documentation and the sample drivers.

The Windows driver paradigm is much more efficient when compared to the VxD model due to the fact that it requires less source code and has a specific standardized code requirement. But, such drivers should not be confused with other backward compatible drivers with versions of Windows that were released before Windows 98. This includes Windows NT 4.0, Windows 95, and Windows 3.1, as well as any versions of Windows that are older than one OS that the drivers were developed for.

This model is backward-compatible with versions that came after it. Because of this, new features of the operating system (OS) may/may not operate properly while utilizing drivers that were developed for older OS versions.

Distinct Categories for Such Drivers

There are three distinct categories for such drivers, which are as follows:

• Filter drivers may be some non-device drivers; but, when the driver does enable the devices, they either provide value to a certain device or affect the behavior of several devices.
• Bus drivers are intended for a bridge, adaptor, or bus controller (although software vendors are free to develop their own bus drivers). Examples of popular types of buses that need bus drivers are USB, SCSI, and PCI.
• Writers create function drivers specifically for a certain piece of hardware, such as a printer.

Summing Up

So, after having a look at the above definitions, you must know everything that is related to the driver. In case of any queries, do connect with us using the comments section below. Subscribe to our newsletter for more such interesting updates.