As, we earlier noted that software is instructions, programs for the computer, but there are various types of software. Software can be classified as
System Software
Software which control the operation of a computer system. They directly interface with the hardware of the computer system. They provide a platform over which application software runs. It controls the execution of application programs. For example Operating System like MS-DOS, MS-WINDOWS XP/ 2003, LINUX
Operating System Software
It is a type of system software. It is a master program which runs in the computer and controls the hardware and running of the application software. It is the software, which is loaded into the memory first, when a computer is started. The operating system manages the data in the computer system, various jobs or task assigned to it and is responsible for the security and proper functioning of the computer. Every general-purpose computer must have an operating system to run other programs. Operating systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers. LINUX, Windows XP/2003, MS-DOS are common examples of operating system.
The major functions of an Operating System are
- Resource management – The resource management function of an OS allocates computer resources such as CPU time, main memory, secondary storage, and input and output devices for use.
- Data management – The data management functions of an OS govern the input and output of the data and their location, storage, and retrieval.
- Task management – The Task management function of an OS prepares, schedules, controls, and monitors jobs submitted for execution to ensure the most efficient processing. A job is a collection of one or more related programs and their data.
- Command Interpretation – The OS establishes a standard means of communication between users and their computer systems. It does this by providing a user interface (Graphical based as in Windows or Character based as in DOS) and a standard set of commands that control the hardware.
Some of the typical uses of an Operating System are
- 1. Executing application programs.
- 2. Formatting floppy or hard or flash disk.
- 3. Setting up directories to organize your files.
- 4. Displaying a list of files stored on a particular disk.
- 5. Verifying that there is enough room on a disk to save a file.
- 6. Protecting and backing up your files by copying them to other disks for safekeeping.
Device Drivers
A device driver is a program that controls a particular type of device that is attached to computer. There are device drivers for printers, displays, CD-ROM readers, diskette drives, and so on. When you buy an operating system, many device drivers are built into the product. However, if you later buy a new type of device that the operating system didn’t anticipate, you’ll have to install the new device driver. A device driver essentially converts the more general input/output instructions of the operating system to messages that the device type can understand. In Windows operating systems, a device driver file usually has a file name suffix of DLL or EXE. A virtual device driver usually has the suffix of VXD.
Application Software
These types of software fulfill a specific user’s requirement. They run over the system software. Application programmers develop the application software. They carry out operation for a specific application. For example accounting software, word processor software, etc. Some of application packages are
Word Processing Software
This software is used to create and to edit documents such as letters, reports, essays etc. The word processing software provides several features for document editing and formatting. In. editing process, text is entered into the document, deleted, copied or moved to another location etc. In formatting process, different formats can be applied on the text to make the document more attractive before to print on the printer. The most popular word processing software programs are Microsoft Word, Word Perfect etc.
Spreadsheet Software
Spreadsheet software is used to store and process data in an electronic sheet having columns and rows. The data is entered into the cells of the sheet. The intersection of a row and a column is known as cell. Each cell is a unique address. The numbers and formulas are entered into the cells and the computer can automatically perform the calculation on numerical data in cells. The spreadsheet software is commonly used for business application such as for performing financial calculations and recording transactions. The most popular example of spreadsheet software is Microsoft Excel etc.
Database Management Software
Database management software is used to create and manage databases. A database is a collection of related information or records on any subject such as records of the books in a library, information about the students of a college etc. Database Management Software stores and manages records in databases. These records can be accessed very quickly when required. The Microsoft Access, Oracle etc. are most popular examples of Database Management Software.
Presentation Graphics Software
The presentation graphic software is used to create slides for making presentations. The presentation graphic software also has pre-drawn clip art images, which can be inserted into slides and can be modified. The PowerPoint is an example of presentation graphic software.
Communication Software
The Communication software is used to exchange information electronically. It is most commonly used software to send and receive information on the Internet. It also allows for sending and receiving faxes directly. The computer files can also be transferred from one PC to another through this software. The Internet Explorer is an example of this software.
Other Software Terms
Utility software
This software is a kind of system software designed to help analyze, configure, optimize and maintain the computer. A single unit of utility software is usually called a utility or tool. They are often rather technical and targeted at people with an advanced level of computer knowledge. Most utilities are highly specialized and designed to perform only a single task or a small range of tasks. However, there are also some utility suites that combine several features in one piece of software. Most major operating systems come with several pre-installed utilities. Disk defragmenter, disk cleanup, backup are common utilities of Windows.
Custom Made Software
Custom Made Software is the software, which is made for fulfillment of the user’s requirement. Software programmers develop the software for the customer, as per the customer’s needs.
Packaged Software
Off the shelf or packaged software is readymade software, which we purchase like a commodity.
Translators
A language translator or a language processor is a general term used for any assembler, compiler or other routine that accepts statements in one language and produces equivalent statements in another language. The language processor reads instructions in a language called source program and converts to other language usually in machine language, also called the executable program. Computers understand machine language which we humans do not understand hence, a translator between human and machine language is needed. Three types of translators are
Assembler
This is a program used to translate assembly language program to machine code. It was used earlier and is not widely used these days.
Compiler
A computer translates program written in high-level language into executable program. Compiler is more complex program than assembler or other system programs and hence they need more memory. The language processor translates the complete source program as a whole in machine code before execution. The C and C++ compilers are best examples of compilers.
Interpreter
It also translates high-level language into machine language. But unlike compilers it translates a statement in program and executes the statement immediately before to translate the next statement. When an error occurs in the program the program is halted and an error message is displayed. An interpreter does not generate a permanent saved object code file. Whenever a program is re-executed the translation process is repeated. The OWBASIC is an example of interpreter.
