Table of Contents
Introduction
In Computer Science, the term software means a set of instructions in the form of a program to control the processing of a computer. These programs are used for various purposes in the computer system. A series of instructions that performs a particular task is called a “program“. The process of software development is also called programming.
Computer software can be broadly classified into two categories according to its purpose. System Software and Applications Software.
System software supports a general programming environment for the development and security of different units of programs by programmers. Such environment is not supported at the hardware level. Operating system is a part of system software.
Application software is used for solving a specific problem for inventory, payroll, spreadsheet, word processor and presentation software, etc.
There is a common misconception amongst individuals that software is data [or set of data]. But it is not. Software tells the hardware how to process the data. Computer software provides instructions that tell the computer how to operate.
Both hardware and software are necessary for a computer to do a useful job. Both are complementary to each other. To take an analogy, a cassette player and the cassettes purchased from the market are hardware. However, the songs recorded on the cassettes are a form of software. The software and hardware are necessary components of the computer. To understand computer software it is desirable to understand programming language. Programming languages constitute the vehicle for understanding the operations of computer hardware and software.
Classification Of Software
The term software in computer science can be compared to the life of any living organism without which it has no significance. If you use a player piano as an analogy, the piano can be thought of as the hardware and the role of music as the software.
A computer can neither think nor make any judgment on its own. Also, it is impossible for any computer to independently analyze a given data and follow its own method of solution. It needs a program to tell it what to do. A program is a set of instructions that are arranged in a sequence that guides the computer to solve a problem. These instructions are written in programming languages [like; BASIC, PASCAL, C…] to help simplify the development of applications. Computer software provides instruction that tells the computer how to operate. Software is also called programs. Programs are usually developed using some language called “programming language“.
Computer Software Can Be Categories Into Two Main Categories: These Are [1]-System Software [2]-Application Software. Function Of Systems Software Are:
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System Software
System Software is that category of software, which manages all the resources of the computer, and is loaded at the beginning or booting of the computer. These are designed to make the computer easier to use. System software controls the operation of input/output devices, memory, and processor, etc. Windows operating systems such as Windows 95, Windows 98, Windows 2000, Windows XP, Windows Vista, etc., are some examples of system software.
Some Functions Of System Software Are:
1- Used by the computer to accomplish a task.
2- Manages all the resources of the computer.
3- Create database and keep it update after every transaction.
4- Arrangement of files in alphabetical order.
5- Controls the internal functions of the computer.
6- Controls other devices connected to the CPUs.
System software can be further compared as a type of program that acts like a conductor in an orchestra. It directs all the activities and sets all the rules for how the hardware and software work together. MS-DOS and Microsoft Windows are examples of system software or operating system software.
Some System Software is inbuilt into the computer. Examples of such software can be given as ROM chips. This software helps to set up the computer and start it.
Types Of System Software: 1- Operating System. 2- Translator. 3- Utility Programs.
From the application programmer’s point of view, the system software should initialize hardware timely and efficiently and also provide a better programming environment. For example, the libraries may consist of a math library [for performing mathematical functions], input/output library, graphics library [to draw different kinds of images, etc.].
Operating System
The operating systems [OS] are the most important system software to run the computer system. Every system must have an operating system. It directly interacts with all kinds of hardware to provide an interface to other system software and application software whenever it wants to access system resources such as CPU, memory, I/O devices.
The fundamental objective of the operating system is to optimize, utilize and control various kinds of resources: CPU, memory, I/O devices, etc. so that the executions of user programs become easier.
The operating system must be loaded into the main memory which is also called booting from the system. One part of an operating system also called the supervisor program, which remains in the primary memory all the time. Other parts of the program are loaded into primary memory whenever it is required, otherwise, it resides on the hard disk. Commonly used operating systems are MS-DOS, MS-WINDOWS, UNIX, LINUX, XENUX, etc.
- History Of Operating System
In the early 1900s, there were no operating systems. The lack of any operating system meant that only one person could use a computer at a time. Even in the research lab, there were many researchers competing for limited computing time. The first solution was a reservation system, with researchers signing up for specific time slots, for performing computing.
The high cost of early computers meant that it was essential that the rare computers be used as efficiently as possible. The reservation system was not particularly efficient. If a researcher finished work early, the computer remained unused until the next time slot or next user comes. If the user time ran out, the researcher might have to pack up his or her work in an incomplete state at an awkward moment to make room for the next user. Let us now discuss the idea of the common operating system which came into existence by computer researchers in the early 1900s.
- Common Operating System
Originally the operating system was created by each company that manufactured a processor and motherboard. So each operating system was proprietary, that is, unique to each manufacturer.
Problem: Changing to a new computer meant your software had to be replaced? Not good marketing. So there was pressure early on to standardize things so that software could be transferred to the new computer [another computer]. This required more standardization in operating systems.
The winner in the PC market was MS-DOS, Microsoft’s Disk Operating System, and its twin at IBM, PC-DOS, also OS written by Microsoft. Now it’s hard to recall those days when each computer had its own unique operating system.
An operating system is system software which may be viewed as an organized collection of software, consisting of procedures for operating a computer and providing an environment for execution of programs. Operating system manages resources of the computer system, such as memory, processor, file system, and I/O devices. Other programs rely on facilities provided by the operating system to gain access to computer system resources.
An operating system may process its task serially [sequentially] or concurrently [several tasks simultaneously]. It means that resources of the computer system may be dedicated to a single program until its completion or they may be allocated among several programs in different stages of execution.
- Functions Of Operating System
The operating system resides in the main memory of the computer system. Following are the basic functions performed by an operating system:
Resource Management: Operating System is responsible for allocating various resources such as I/O devices, memory, etc. to the user effectively. It schedules the processes by time management and memory management. It also keeps track of all the I/O devices and CPU so that there would be no wastage of time and all the devices remain busy all the time.
File Management: File Management Program makes it easier to manage your files and folders. Many programs were written to help the user find files, create and organize directories, copy, move, and rename files.
Disk Management: Programs involve formatting and de-fragmenting disks. The term de-fragmenting means, putting files on the disk so that the whole file is in sequence. This reduces the time to access the file. Some disk management programs even let you specify the files that are accessed often, like the operating system itself and other frequently used programs.
Memory Management: Memory management software handles where programs put their current data in RAM. They move certain memory-resident items out of the way. This can effectively increase the memory available by getting all the unused pieces together in one spot.
Security Of Data: The operating system handles different programs and data in the memory, so that they do not mix or interfere with each other. It protects your computer and data from attacks and damage from outside. Only trusted websites and programs could be allowed to access your computer with security software.
Translator
The translators are the system software. They are used for translating the instructions into computer readable form i.e., binary form. The instructions are written in any computer programming language such as C or some other programming language and are converted to computer-readable form. There are many programming languages such as machine language, assembly language, high level language. These languages allow a person to write the software programs for system maintenance as well as applications. These instructions are converted to binary form by translator software such as assembler, compilers, and interpreters.
1- Assembler:-
The first step in the evolution of programming language was the development of the assembly language. In an assembly language mnemonics are used to represent the operation codes and strings of characters to represent the address. It is the translator program which is used to translate the assembly language instructions in binary form. The assembler converts the symbolic instructions code of assembly language into machine language.
In order to execute an assembly language program on a computer, it should first be translated to its equivalent machine language program. The translator which does this is known as assembler. The input to an assembler is the assembly language program and is known as source program. Its output is the equivalent machine language program and is known as the object program.
The assembler is a system program which is supplied by the computer manufacturer. Assembly language programs are also called low level language programs. The main advantage of using an assembly language programming is the efficiency of the machine language programming resulting from it. Some of the commands which are used in assembly language programs are READ, ADD, STO & HLT, and the function of these commands are read, add, stop and halt of the execution of instruction of a program.
Disadvantages Of Assembly Language Are:-
1- It is machine dependent i.e., the programs written for one model of computer can’t be executed on another model.
2- It is very difficult to write programs in assembly language and needs rigorous training and expertise.
3- Assembly language programming is time consuming in comparison to high level language programming.
2- Compiler:-
Since, computer doesn’t directly understand high-level language programs, written in English language to which it has to process. There is need for translators to translate the high-level language into machine language called compiler. Compilers take input as high level language programs and produce output the machine language code of the machine on which it is executed.
These high level language programs must be translated first into machine language and the software which is used to convert high level language programs into machine language [in the form of the binary number, 0 & 1], is called compiler.
Compiler scans the entire program first and then checks for syntax [grammatical] errors. If there is any error, the computer generates a printout of the errors it has detected. Process of detecting and removing errors from a high-level language program is called debugging.
3- Interpreter
It is another translator program for high level language. It analyzes and executes high level language program statements line by line without looking entire program at one go [as in the case of the compiler]. Each time of the program is executed; every line is checked for syntax errors and then, is converted to equivalent machine code. It is slower than the compiler.
Difference Between Compiler And Interpreter
Compiler: [1] – Scans entire program first and then converts it into machine code. [2] – Translates the entire program to machine code, after debugging the program and execution takes place in the end. [3] – Program execution time is less. [4] – Debugging process is slow. [5] – Suitable for large programs. [6] – Programs produced by compilers run much faster than interpreters.
Interpreter: [1] – Scans program line by line. [2] – After each execution every line is checked for syntax errors and then converted to object code. [3] – Program execution time is more. [4] – Debugging process is fast. [5] – Suitable for small programs. [6] – Programs produced by interpreters run slower than compilers.
Utility Programs
A utility program performs tasks related to the maintaining of your computer’s hardware or data. Some utility program is included with the operating system and some is updated every year/time you become online with internet. By updating it becomes better equipped to handle the needs and security of computer systems.
A Few Examples Of Utility Programs Are:
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- Software to convert a .pdf file format into a .doc format and vise versa.
- Multimedia converter software to convert mp3 file format to mp4 or MPEG etc. and vise versa.
- Sort/Merge software for sorting and merging large volume of business data into a single sorted list.
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Application Software
Although system software is essential for running your computer and managing all its resources. You need application software to enable the computer to solve a specific data processing task such as payroll processing, inventory control, and insurance company data. A software package is a group of programs for solving a specific task.
A number of powerful application software packages, which do not require significant programming knowledge, have been developed. These are easy to learn and use as compared to the programming languages. Software can be used by people to solve general problems. It can be used to do more than one task such as
- Planning
- Writing
- Record Keeping
- Calculating
- Communicating
- Drawing
- Painting etc.
There is no limitation of activities that can be done by this software. What can be done with general purpose application software is only limited by the imagination of the user. Use of variety of software depends upon the requirement of the type such as letter typing, making presentations, making tables, and storing data in a database.
Some Examples Of Such Application Software Are:
1- Word Processing Package.
2- Spreadsheet Package.
3- Graphics Software.
4- Database Management Software.
Word Processing Package
Word processing means typing, editing, and formatting the documents such as letters, documents, books, and balance sheets, etc. In general word, processing refers to the processing of words i.e., simple text. A word processor is such a software package that allows the user to create and edit documents.
Creating the documents involves typing text in the internal memory of the computer system and saving it on the disk. Editing a document involves correction of spelling mistakes and deleting or moving words, sentences or paragraphs, i.e., arranging text at the appropriate place in the document.
Microsoft Word is a word processing software which can be used to create, edit, save, and print documents. Let us now discuss the menus of this software.
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- Title Bar: It displays the name of the program, name of the currently active word document, and the control button, etc.
- Menu Bar: It is placed below the title bar and is used for performing various tasks, such as open, close, format, etc. of the document.
- Status Bar: It displays information about the active task on which user is currently working. This includes the page number, line number, etc. on which the user is currently working.
Advantage Of MS-Word:-
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- Type a document through the keyboard and save it on the disk.
- Correct, delete and insert characters, words, lines anywhere in the document.
- Retrieve documents from the disk as and when required.
- Move or copy paragraphs from one place to other or from one file to other.
- Formatting of the document as per the need of the user.
- Searching of files in folders of the system.
- Save the edited document on the disk.
- Print a letter or document.
Electronic Spreadsheet Package
Although MS-Word is a very good software package for word processing tasks, but it is not convenient in entering data in tabular form, doing the mathematical calculations, and presentation of results in graphical form.
MS-Excel software package is used in place of the paper sheet or ledger used by the people in management. It is used to store information in the memory of computer system, calculate the result, and display information on computer screen in a desired manner. Some common applications of MS Excel worksheets are: Inventory Control, Payroll, Income Tax Calculation, Price List, and Invoice Billing. Let us now discuss the menus of this software.
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- Title Bar: It displays the name of the program, name of the currently active MS Excel worksheet, and control button, etc.
- Menu Bar: It is placed below the title bar and is used for performing various tasks, such as open, close, format, etc. of the worksheet.
- Status Bar: It displays information about the active task on which user is currently working. This includes the page number, line number, etc. on which user is currently working.
Features Of Spreadsheet:-
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- Worksheet contains rows and columns. There are 65536 rows and 256 columns in a worksheet of MS Excel.
- Intersection of rows & columns gives a cell, which is used for data entry.
- Each cell of the worksheet has a unique address.
- New rows and columns can be inserted into a worksheet.
- Cell address is used for defining formula in any worksheet.
- Entry in worksheet may be numbers, character values, or numeric values.
- Currently active cell is identified by the position of the cell pointer.
- The cursor can be moved from one cell to another by arrow keys.
Advantage Of MS-Excel Spreadsheet:-
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- Result of calculation is accurate and fast.
- Project reports can be prepared easily and quickly by the user.
- Worksheet is saved in electronic file and can be modified when required.
- Mathematical formula’s such as trigonometric formulas, statistical formula’s are inbuilt along with this software and can be used for the analysis of project results.
- Data can also be used to generate graphs for the comparison and analysis of project reports.
- Two worksheets can be merged for the purpose of report generation from two worksheets.
Graphic Software
Graphics software is used to create and manipulate presentation graphics, freehand graphics, charts, etc. Some common graphic software’s are MS Power Point, Lotus-Graphics, Harvard Graphics, etc. Image processors such as Photo-paint and Photoshop are also called graphic software.
Here, we will discuss some components of graphics software, Power-Point. Power-Point is a complete presentation graphics package. It gives you everything you need to produce a professional looking presentation text handling, outlining, drawing, graphics, clip and art, and so on. It also offers rich speaker support and aids to help you create truly effective presentations.
Power-Point makes you the presenter and independent producer of your own high equality presentations.
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- Title Bar: It is located at the top of the screen, displays the name of the presentation.
- Menu Bar: It is located below the title bar and lists the options.
- Status Bar: Used to display messages regarding page number, slide number etc. at the bottom of the window.
Advantage Of Power-Point:-
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- Create a blank presentation.
- Text can be added by using the text box.
- Change the fonts, size, and color of the text.
- Add drawing objects.
- Presentations can be saved in the memory of the computer.
- Pictures and sound files can be inserted at the appropriate place in the presentation.
- Project reports can be presented by using PowerPoint.
Database Management System [DBMS]
DBMS has its role in almost every field of our life such as school, office, industry, etc. It allows storing and managing a large amount of data. Various DBMS software’s are FoxPro, Oracle, SQL, Sybase, MS Access, etc.
Features Of DBMS:-
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- Creating data files on a computer.
- Maintaining these files by adding, deleting, editing, and updating a given set of data items.
- Generating reports based on data files.
- Querying on those data files.
- Generating reports.
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