Software
A PC is incapable of performing any task with the hardware alone. It requires instructions that determine whether it will function as desired or not. Like data, instructions are also entered via the keyboard. In computer terminology, a set of instructions is called a program and one or more programs are called software.
Software used on computers may be of different types. Some important classes of software are:
Application Software
We spoke of computer applications and identified certain areas where computers are being used today. Software specially suited for specific applications is now available in the market. For example, software for billing systems, accounting software or software that enables the creation and storage of documents. Such software is called application software since it is designed for a specific application.
Application software that takes care of a variety of business and corporate needs can now be bought off the shelf. These are also called standard software packages. They are reasonably priced and can run on any standard PC.
Two popular standard software packages are Financial Accounting and Inventory Control packages.
In case a user is not satisfied with the available package, because it does not meet all the requirements, the package can be modified.
However, if the package cannot be modified, the user can opt for a customized software package. A customized package is developed for a user's specific needs and may not be relevant to any other user.
Though these packages are for very specific applications, there are general application softwares like database management systems (DBMS), spreadsheets and word processors.
Using a DBMS software, a user can maintain large volumes of data that can be modified, updated and queried.
A spreadsheet package allows a user to enter numeric data, specify formulae and perform calculations. Graphs can also be generated from the given data. The special feature of automatic recalculation allows changes made in any one item to reflect in all items dependent upon the first one.
A word processing package converts a PC into a sophisticated typewriting machine. It has the facility to perform spell checks, provide for synonyms, and allow changes or corrections in the document without having to re-type the entire document.
Compiler Software
Consider the case of four persons, Leonardo, Chou, Ivan, Hari, who understand and speak Spanish, Chinese, Russian and Hindi, respectively. To be able to understand each other, they would require some person or persons who could translate whatever is spoken into the language each understands.
Similarly, since there are so many programs written in different computer languages, the hardware also needs a translator to convert the computer language into a form that it can understand.
The computer only understands a language of electrical signals, called machine language.
Software called the compiler converts the computer language into machine language. For example, there is a C compiler that converts programs written in the C language to machine language.
Operating System
Besides the application software and compiler software, there is a third kind of software, called the operating system, which is very important for the working of the PC.
When a user wants to store any data or program, the data or program is stored at a location that is known only to the operating system. Therefore, the operating system performs the task of storage management.
Besides storage management, the operating system also performs device management. For instance, when a user wants to print information on the printer, or display information on the VDU, he or she does not have to bother about the actual transportation of the information from the internal storage to the VDU or to the printer. The operating system takes care of it.
Computer Languages
All application software packages are written in computer languages. There are various computer languages like C, C++, FORTRAN and Pascal. Each language is best suited for a particular application.
C and C++ languages are used to develop highly complex software. FORTRAN is used for scientific applications
Each language has its own vocabulary. There are some packages like FoxPro, MS Access and Sybase that are more English-like. Thus, even non-computer professionals, like executives and managers who have never studied computer science, can learn to use these languages.
Since each language has its own vocabulary, each language differs from the other.