Understanding Device Drivers

Device drivers play a critical role in the functioning of your computer. Every device attached to your computer from the keyboard to the graphics card requires a driver. The best device drivers will increase performance and enhance stability. A malfunctioning driver can bring your system to a grinding halt or even hide malicious software. Understanding how all this is possible can lead to a safer and more enjoyable computing experience.

Before getting into the details of how a device driver works, you need to know a little bit about what separates them from other software. While the specifics vary depending on your operating system (be it Windows, Linux or OS X) some general concepts remain the same.

One of the key points of separation is who is going to be using it. Unlike other software, device drivers are not designed to interact directly with users. Device drivers work with the hardware they support and the the lowest level of the operating system called the kernel. With help from device drivers, the kernel translates the raw electrical chatter from your computer's hardware into something easier for the rest of the operating system and the programs you interact with to understand.

Due to the critical role of the kernel, it will typically be the first thing to load when your computer starts. It will install its self in a protected area of the computer's memory that most programs have not direct access to. Since they perform a similar function and require similar access, device drivers are loaded shortly after and live in this protected and privileged area as well.

When an application requires hardware help, it must wait for the request to be translated by the device driver and the kernel. In this way, device drivers can affect every application on your system. If your keyboard driver was lazy, both your word processor and your email client would appear to be sluggish and unresponsive. Also, should the keyboard driver fail, all your running application would stop responding.

In addition to being stable and responsive, a device driver must be trustworthy. The higher levels of the operating system have no way of verifying the information given by device drivers. They must assume that their requests for action and information are fulfilled accurately. As a result, a malicious device driver can do things that not even your anti-virus program can detect.

Using the tools that operating system companies give developers to write device drives, malicious authors can create 'rootkits'. Software that masquerades as a legitimate translator, but in fact intercepts commands for it's own nefarious purposes. Since they function below the level of other software, they are very difficult to detect and can require special tools to detect and remove.

With the large number of hardware vendors creating hardware and software for it, the Microsoft's Windows operating system has had more than its fair share of device driver woes. These normally come from well intentioned manufactures releasing buggy drivers, but there have also been cases of intentional malevolence as well.

To combat both problems, Microsoft created the a driver signing program. Before making their software public, device manufactures can get Microsoft's digital seal of approval applied. When you attempt to to install a driver without this seal, you will either receive a warning message or in some cases, Windows will simply refuse to accept the driver. It is worth noting that some legitimate drivers are, for various reasons unsigned.

While device drivers that have been given Microsoft's approval are not likely to contain directly harmful code, driver software is rarely bug free on the first run. Whenever you are having system problems that seem to affect more than one application, regardless of what operating system you use, checking for updated device drives is a good place to start.