Software is a set of computer programs, procedures, and documentation that perform some task on a computer system. Software can be divided into two categories: application software and system software. Application software includes word processors, spreadsheets, databases, and other specific applications that perform user-oriented tasks such as bookkeeping, managing customers or clients, preparing taxes, designing forms and labels, and writing letters. System software provides an interface between hardware and application programs. It includes the operating system (OS), which controls the basic operation of the computer; utility programs that maintain the integrity of the OS and support its functions; device drivers that control communication between specific hardware devices and the OS; compilers that translate instructions written in high-level programming languages into machine code for execution by the CPU; linkers that combine object code modules into an executable program; loaders that copy an executable program from secondary storage to main memory for execution; debugging tools that aid programmers in locating errors in source code or object code.
The term “software” was first used in print by John W. Tukey in an article published in 1958 entitled “New Tools for Mathematics.” However,Tukey’s definition was restricted to mathematical algorithms implemented on punched cards. In 1969 Jürgen Hintikka proposed “software science” as a new field complementary to mathematics and physics. This term was also used in print by American Heritage Dictionary editors in their second college edition (1982). By 1986 this usage had become common enough to appear on the cover of Scientific American magazine. In January 2000 IEEE Spectrum magazine suggested “computational science” as a more accurate name for what is now called scientific computing because it better reflects recent developments such as grid computingand distributed systems architectures suchas Web services.