There are a number of reasons to be interested in the writing of linux device computer drivers. The rate at which new hardware becomes available (and obsolete!) alone guarantees  that driver writers will be busy for the foreseeable future. Individuals may need to know about drivers such like windows drivers in order to gain access to a particular device that is of interest to them. Hardware vendors, by making a linux driver available for their products, can add the large and growing linux user base to their potential markets. And the open source nature of the linux system means that if the driver writer wishes, the source to a driver / driver download can be quickly disseminated to millions of users.

When writing drivers, a programmer should pay particular attention to this fundamental concept / write kernel code to access the hardware, but don’t force particular policies on the user, since different users have different needs. The driver should deal with making the hardware available, leaving all the issues about how to use the hardware to the applications. A driver, then, is flexible if it offers access to the hardware capabilities without adding constraints. Sometimes, however, some policy decisions must be made. For example, a digital I/O driver may only offer byte-wide access to the hardware in order to avoid the extra code needed to handle individual bits.