Software is a Program commercially prepared and tested in software by one or a group of programmers and system analyst to perform a specified task. Software is simply set of instructions that cause a computer to perform one or more tasks. The set of instructions is often called a program or, if the set is particularly large and complex, a system. Computers cannot do any useful work without instructions from software; thus a combination of software and hardware (the computer) is necessary to do any computerized work. A program must tell the computer each of a set of tasks to perform, in a framework of logic, such that the computer knows exactly what to do and when to do it. Data are raw facts and ideas that have not been processed while Information is data that has been processed so as to be useful to the user
3.1 Classification of software
Software can be broadly classified into system software and application software
3.2 System software
Consists of programs that control operations of the computer and enable user to make efficient use of computers. They coordinate computer activities and optimize use of computers. They are used to control the computer and develop and run application programs examples of jobs done by the system software are management of computer resources, defragmentation etc. They can be divided into;
1. Operating system – is a complex program and most important program that
runs on a computer and which controls the operation of a computer. It 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. In general the operating system supervises and directs all the software components and the hardware components. Sophisticated operating system could handle multi-processors, many users and tasks simultaneously. Examples of computers operating systems are UNIX, Microsoft windows 95/98, Windows NT, Windows 2000, Windows XP, Windows Vista and Linux.
2. Service programs are programs designed for general support of the processes of a computer; “a computer system provides utility programs to perform the tasks needed by most users”. The service programs can further be divided into;
Utilities Performs a variety of tasks that maintain or enhance the computer‟s operating system .Utility programs are generally fairly small.
Each type has a specific job to do. Below are some descriptions of utilities.
- Anti-virus applications protect your computer from the damage that can be caused by viruses and similar programs
- Compression utilities make files smaller for storage (or sending over the Internet) and then return them to normal size.
- Data recovery utilities attempt to restore data and files that have been damaged or accidentally deleted.
- Disk defragmenters reorganize the data stored on disks so that it is more efficiently arranged.
- Firewalls prevent outsiders from accessing your computer over a network such as the Internet.
Development programs are used in the creation of new software. They comprise of sets of software tools to allow programs to be written and tested. Knowledge of appropriate programming language is assumed. Tools used here are
- Text editors that allows one to enter and modify programs statements
- Assembler- allows one to code in machine programs language .i.e. processor specific
- Compilers-makes it possible for programmer to convert source code to object code which can be stored and saved on different computers.
- Interpreters-used to convert source programs statement by statement as it executes the program without being compiled first.
- Libraries– commonly used parts or portions of a program which can be called or included in the programmer‟s code without having to recode that portion.
- Diagnostic utilities-used to detect bugs in the logic of program during program development
Communication programs- refer to programs that make it possible to transmit data.
3.3 Application software
Are programs for user to do their jobs e.g. typing, recording keeping, production of financial statements, drawing, and statistics.
General/ready made software is developed to perform a variety of tasks, usually determined by use. Such software can be customized by user to achieve specific goals e.g. ms office which is a suit of programs performing a variety of tasks e.g. word processing for producing documents, database for storing, retrieving and manipulating data and various calculations on spreadsheets. General purpose programs are discussed below;
- Word processing applications. Writing tasks previously done on typewriters with considerable effort can now be easily completed with word-processing software. Documents can be easily edited and formatted. Revisions can be made by deleting (cutting), inserting, moving (cutting and pasting), and copying data. Documents can be stored (saved) and opened again for revisions and/or printing. Many styles and sizes of fonts are available to make the document attractive. Example: MS Word, Word Pad etc.
- Spreadsheet applications. spreadsheet software permits performance of an almost endless variety of quantitative tasks such as budgeting, keeping track of inventory, preparing financial reports, or manipulating numbers in any fashion, such as averaging each of ten departmental monthly sales over a six-month period. A spreadsheet contains cells, the intersection of rows and columns. Each cell contains a value keyed in by the user. Cells also contain formulas with many capabilities, such as adding, multiplying, dividing, subtracting, averaging, or even counting. An outstanding feature is a spreadsheet’s ability to recalculate automatically. If one were preparing a budget, for example, and wanted to change a variable such as an increase in salary or a change in amount of car payments, the formulas would automatically recalculate the affected items and the totals.. Example: Excel, Lotus1-2-3 etc.
- Database software: A database contains a list of information items that are similar in format and/or nature. An example is a phone book that lists a name, address, and phone number for each entry. Once stored in a database, information can be retrieved in several ways, using reports and queries. For example, all the names listed for a given area code could be printed out and used for a commercial mailing to that area. Examples of database software is Ms Access, Dbase, Oracle etc.
- Presentation software: for making slide shows. Allows users to create visual presentation A speaker may use presentation software to organize a slide show for an audience. Text, graphics, sound, and movies can easily be included in the presentation. An added feature is that the slide show may be enhanced by inclusion of handouts with two to six slides printed on a page. The page may be organized to provide space for notes to be written in by the audience as the presentation ensues. An example of this is Power Point. Preparation of the software is simplified by the use of ‘wizards’ that walk the user through the creation of the presentation.
- Desktop publishing software: This software permits the user to prepare documents by using both word-processing devices and graphics. Desktop publishing software uses word-processing software, with all its ease of entering and revising data, and supplements it with sophisticated visual features that stem from graphics software. For example, one can enhance a printed message with virtually any kind of illustration, such as drawings, paintings, and photographs. . Examples of Desktop publishing software is PageMaker, Corel Draw, and Ms Publisher
- Multimedia applications for creating video and music. Allows users to create image, audio, video etc. Example: Real Player, Media Player etc.
- Activity management programs like calendars and address books
NB: Nowadays most of the general purpose software is being sold as a complete software suites such as Microsoft office or Lotus SmartSuite. These suites offer four or more software products packaged together at a much lower price than buying the packages separately.
Tailor made/special purpose software Tailor-made computer system refers to computer application developed by in-house IT personnel or outside software house according to specific user requirements in a firm. They are developed for given purpose e.g. Payroll system, stock control system etc.
3.4 Chapter Review Questions
- Which of the following is not General Purpose software?
(a) Stock Control
(b) Word Processing
(c) Internet software
(d) Presentation
- Which of the following is not part of the Ms. Office suite?
(a) Ms Word
(b) Ms Access
(c) Outlook
(d) Ms QuickBooks
- Which of the following is not an operating system
(a) Windows XP
(b) Windows Explorer
(c) Ms Dos
(d) Linux
- Which of the software below would assist a secretary in preparing a report for an annual general meeting?
(a) Ms Word
(b) Ms Access
(c) Outlook
(d) Ms QuickBooks
- Which of the software below would assist a salesman in recording daily sales for different items for which he needs totals among other analysis?
(a) Ms Word
(b) Ms Access
(c) Outlook
(d) Ms Excel
