Software Types of Programs

Software

A computer that is dedicated to running a program that controls another device is an embedded system. An embedded system is usually embedded inside the device it controls. Usually they run just one program that is permanently kept in a special kind of main memory called ROM (for Read Only Memory). More processor chips are sold per year for embedded systems than for all other purposes.

Software is the programs and data that a computer uses. Software is kept on some hardware device such as a hard disk or floppy disk, but it itself is intangible. Say that you have a floppy disk with a program saved on it. Now say that you erase the program from the disk. The atoms and molecules of the disk are the same ones as before, but now the program is "gone." The intangible software has been removed without removing anything tangible.

Software consists of both programs and data. Programs are lists of instructions for the processor. Data can be any information that a program needs: character data, numerical data, image data, audio data, and countless other types. The distinction between programs and data is not as clear-cut as you might think, however.

Fundamental Idea: Both programs and data are saved in computer memory in the same way. The electronics of computer memory (both main memory and secondary memory) make no distinction between programs and data.

The insight that both programs and data can be saved using the same electronic methods is one of the most important ideas in computer science. Computer systems can use their memory for whatever needs arise.

Types of Programs

There are two categories of programs. Application programs (usually called just "applications") are programs that people use to get their work done. Computers exist because people want to run these programs. Systems programs keep all the hardware and software running together smoothly. The difference between "application program" and "system program" is fuzzy. Often it is more a matter of marketing than of logic.

Application Programs	Systems Programs
·     Word processors ·     Game programs ·     Spreadsheets ·     Data base systems ·     Graphics programs ·     Web browsers	·     Operating system. ·     Networking system. ·     Database system. ·     Programming language software. ·     Web site server. ·     Data backup.

The most important systems program is the operating system. The operating system is always present when the computer is running. It coordinates the operation of all the hardware and software components of the computer system. The operating system is responsible for starting application programs running and finding the resources that they need. When an application program is running, the operating system manages the details of the hardware for it. For example, when you type characters on the keyboard, the operating system determines which application program they are intended for and does the work of getting them there.

Modern operating systems usually come with a user interface that enables users to easily interact with application programs (and with the operating system itself) by using windows, buttons, menus, icons, the mouse, and the keyboard. Examples of operating systems are Unix, Windows 98, Windows NT, Linux, Solaris, and System 7.