The first component runs in user mode and presents the user interface. The second component runs in kernel mode and has access to the core operating system data. The component that runs in user mode is called an application, and the component that runs in kernel mode is called a software driver.
A software driver is not associated with a hardware device. This diagram illustrates a user-mode application communicating with a kernel-mode software driver. Software drivers always run in kernel mode.
The main reason for writing a software driver is to gain access to protected data that is available only in kernel mode.
However device drivers do not always need access to kernel-mode data and resources. So some device drivers run in user mode. For more information about processor modes, see User Mode and Kernel Mode.
There is a category of driver we have not mentioned yet, the bus driver. To understand bus drivers, you need to understand device nodes and the device tree.
For information about device trees, device nodes, and bus drivers, see Device Nodes and Device Stacks. As long the driver you're downloading comes from a reputable source, like the manufacturer of the device, it is considered safe. If you have to download a driver from a third party , it's difficult to know if they've modified the driver code.
Unfortunately, like any computer software , drivers can also be infected with viruses and other malware. We recommend having an antivirus installed and running on a computer before you download and install a driver from a third party. If you mistakenly download the wrong driver and attempt to install it on your computer, it will fail during the install.
However, it's possible to install a driver for a device that does not exist. However, even if this is done, you'd only get errors about the device not being detected or see problems with the non-existent device in Device Manager. Installing the wrong driver on a computer that's working would not cause it to stop working. However, if you removed a working device and then installed the wrong drivers, that may cause problems. What devices need drivers?
What devices may not need drivers. What happens if a driver is not installed? They give guest operating systems the illusion of accessing hardware. Drivers are often updated by the manufacturer for multiple reasons. Manufacturers often discover glitches or errors called bugs that can be fixed with an update. Updates can be used to add new features to a device or increase its performance. Security patches are also implemented through updates to remove vulnerabilities.
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This compensation may impact how and where products appear on this site including, for example, the order in which they appear. TechnologyAdvice does not include all companies or all types of products available in the marketplace. Sign in. Log into your account. Forgot your password? Password recovery. Recover your password. Here are a few additional resources related to drivers:. Many problems that can be isolated to a particular piece of hardware aren't problems with the actual hardware itself, but issues with the device drivers that are installed for that hardware.
Some of the resources linked above should help you figure all that out. When a driver update is available from a hardware manufacturer, it will be available for free from their website.
You should never have to pay to update drivers unless you're paying for a driver updater program, but even then, the specific drivers themselves should not need to be purchased. Beyond the basic software-driver-hardware relationship, there are some other situations that involve drivers and that don't that are kind of interesting.
While this is less common these days, some software is able to communicate directly with some types of hardware — no drivers necessary! This is usually only possible when the software is sending very simple commands to the hardware, or when both were developed by the same company, but this can also be thought of as a kind of built-in driver situation. Some device drivers communicate directly with a device, but others are layered together.
In these situations, a program will communicate with one driver before that driver communicates with yet another one, and so on until the last driver actually performs the direct communication with the hardware. These "middle" drivers often don't perform any function at all other than verifying that the other drivers are working properly. Regardless, whether there is one driver or multiples working in a "stack," all of it is done in the background without you having to know, or do, anything.
Windows uses. SYS files as loadable device drivers, meaning they can be loaded on an as-needed basis so that they're not always taking up memory — other drivers are in the DLL or EXE format.
The same is true for Linux. KO modules. WHQL is a testing process by Microsoft that helps prove that a particular device driver will work with a specific version of Windows. You might see that a driver you're downloading is or isn't WHQL certified. You can read more about Windows Hardware Quality Labs here. Another form of the driver is the virtual device driver.
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