Specialized Device Drivers

All device drivers that are accessible to application logic are either: (1) Character device drivers that can be accessed via the standard driver operations (open(), close(), read(), write(), etc.), or (2) block drivers that can be accessing only as part of mounting a file system or other special use cases as described in the preceding paragraph.

In addition to this, there are also specialized “drivers” that can be used only within the OS logic itself and are not accessible to application logic. These specialized drivers are discussed in the following section.

Note

While special drivers are internal, in some cases there are also character/block drivers that sit on top of these special drivers and thus expose them to applications.