Programs tell a computer what to do. There are two different kinds of programs: systems programs and applications programs. All programs accomplish some kind of work. Systems programs help operate the computer itself; the goods systems of a computer are controlled by systems programs. An applications program carrier out a task for the user. In fact, application programs get users work done, and systems programs help a computer manage itself.
A few of the systems programs, that a PC needs to manage its operating, are permanently built into it. These are called firmware, because they are permanently stored in read only memory. These programs do the most fundamental supervisory and support work, such as providing essential services that all the application programs use. These service programs are called the Basic Input/Output system (BIOS).
Other systems programs built on the foundation created by the BIOS provide a higher level of support services. Operating systems, such as DOS and windows are examples of there higher-level systems programs.
