CHAPTER 1 WHAT IS COMPUTER? ODULAJA G.O., ALABA O.B., & USMAN O.L.
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[email protected] (Computer and Information Sciences Department, TASUED) INTRODUCTION DESCRIPTION: Odulaja (2010) defined computer as an electronic machine that can accept data as input, process it, store it, give output and if networked, can transmit either the data or the generated output to designated place(s) under the direction of the user. As a data processing machine, this definition uniquely define computer in such a way that sets it apart from other data processing machine such as typewriter, musical keyboard, talking drum and electronic calculator. This definition, by all means qualifies mobile devices such as Smartphones, android phones and Infinix phones as handheld computers. This broad definition not only shows computer to be data processing machine but reveals the pentagonal capabilities of modern digital computer that differentiates it from any other data processing machines such as typewriters, fax machines, television, transistor radio and the likes. There is none of these other machines that combines all these capacities into one device the way computer does. Computer is an everywhere useful (ubiquitous) machine. It is a unique machine that combines the potentials in electronics, mathematics, physics, nanotechnology, etc together with the power of programming to achieve unprecedented feats. As a result, computer has infiltrated practically all disciplines of human endeavours, has contributed immensely to national development and human capacity building, growth and expansion of corporate and individual business ventures, and it has made existence of the information super highway – the World Wide Web (WWW) found on the Internet possible. Today, as a standalone system or part of the local area network (LAN), computer can be found in personal and corporate offices as part of their data processing and transmission system or the central information system and database. Computer is used to do many things, ranging from data processing, storage to data processing and output. It is used in music, photography, and other sectors like commerce, industries, agriculture, transportation, security etc. In education sector alone, its usefulness spans through all the educational spectrum: to prepare for class, teach the students, set exams, conduct exams (e-exams, CBTs, to assess students), invigilate exams (using computerized CCTV), mark exams, release results and even store or transmit results and decisions. The same can be said of several other sectors like banking, insurance, book production espionage etc. Because computer, be it a standalone system, part of the nodes in a computer network or a mobile phone / Smartphone is a programmable machine, this makes is very versatile and dynamics in nature. Mastering the dynamics of computing machines is the secret to getting the best out of this unique machine. In the light of this, it is now mandatory to be computer literate sufficiently and successfully to apply it in advancing our profession. Because of advances in nanotechnology and electronic, miniaturization of computer technology became possible. This has resulted in lower cost of computing and smaller, and production of more portable computers. This ranges from handheld mobile devices to industrial super computers. (fig. 1).
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Fig 1.1 Handheld Computer / Personal Digital Assistant(PDA) Source: James Leynse/Corbis @ Microsoft ® Encarta. Physical and Logical Components of Computer Physically, a typical computer system consists of a system unit, input devices, storage devices, and output devices. The central processing unit CPU or the processor unit contained in the system unit consists of an arithmetic/logic unit, registers, control section, and internal bus. The arithmetic/logic unit carries out arithmetical and logical operations. The registers store data and keep track of operations. The control unit regulates and controls various operations. The internal bus connects the units of the CPU with each other and with external components of the system. For most computers, the principal input devices are a keyboard, scanner and a mouse. Storage devices include hard disks, CD-ROM drives, and random access memory (RAM) chips. Output devices that display data include monitors, computer speakers and printers. (Fig.2). Modern computers process data and generate output for storage or transmission in three types or forms: Textual data – composed of alphabets, special characters and digits such as letters and documents. Oral data – Data in form of sound such as lecture material, music and sermons. Graphical Data – this are data in form of graphics, images or pictures such as posters, banners etc.
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FIG. 1.2: LOGICAL STRUCTURE OF COMPUTER SYSTEM Source: Microsoft ® Encarta Characteristics, Benefits and Uses of Computers 1. Accuracy in Processing – Computer processes given data accurately. It does not make mistakes. Any identified error in computer-generated work can be traced to human. That why we say computer is a garbage in, garbage out machine. 2. Speedy Processing – computer processes data very fast such that billions of instructions can be processed within a second by certain computer machines. Computer can process and transmit data at the speed of light (it is on record that light travels at 186,000 miles per second). 3. Consistency – Computers, given the same set of data and the same set of instructions or formula, can carry out a job repeatedly without making mistake or tiring. It gets the same result consistently without fatigue or altering results. 4. Precision – Computer is a very precise machine that can be used to compute and generate highly accurate results involving very long numbers such as the one used in astronomy. 5. Ease of Access – Computers are now very easily accessible to many people, if not as a personal system at least as a hired one. The services of the computer are available in several places for a token fee in places such as cyber cafe, Computer Centers and Computer Bureau. Nowadays, almost all post basic (primary) school have a computer lab. Even some good private primary and nursery schools boast of a computer laboratory / outfit used in support of training of their pupils. 6. Tidiness - Computer work output can be quite neat and tidy and leading to a “paperless office”. A paperless office is one in which paper documents has been replaced with their softcopies, the electronic equivalent, the trash-bin is replaced with the recycle bin, and the cabinets and drawers of paper files replaced with an electronic file or database. This makes for a tidier and neater office environment. To correct a mistake on a document, a correcting fluid is not needed, and there is no scar left after correction. 3
7. Handling of High Volume Jobs - Computers can process and store high volume of jobs without getting bored or fatigued. Unlike man, computer will neither gain nor lose weight as a result of working for long on a stationary position. 8. Safety – Softcopies of documents are safer on the computer. They are not susceptible to rodents, and insects like cockroaches. They can also escape from flood and fire disasters if backed up elsewhere such as in the cloud. Besides, letters don`t get dog-eared, chopped off with age or wears out. Even mould cannot spoil computer-based documents. Some cars today have inbuilt computerized automated safety kits. 9. Time and Manpower Conservation - Because of computer`s fast processing power, it uses little time to process great amount of jobs, thus saving both time and manpower. Computer can thus process the job of hundreds of men in few minutes with less cost to the organization. The time gained can be harnessed towards more productive ends. 10. Data transfer - Transferring data locally from one computer system to another, and intentionally from one continent to another has become quite easy with the use of computer networks facilities. 11. Office and Home automation - Automation (automatic control and use of) electronic office machines and home appliances even from remote ends has become commonplaces as a result of computer programmed instructions. In an automated home, a mother at her office can remotely control her children access to electronic gadgets at her home such as computer, television etc 12. Security of Properties - This is obtainable in the case computer programmed security doors and locks found in big homes, office, bank entrances, hotels, and automobiles. Even programmed security chips has been embedded in migratory birds and satellites to both monitor their movement and ensure their functional security. Computerized sensors help protect pipelines from vandalization. 13. In Teaching and Learning – Application has been made tremendously of computer in education. E-learning, E-Tutor, Computer aided instruction (CAI) etc, are now commonplace, courtesy of computer support. 14. In Design and Manufacturing – As found in computer aided design (CAD), computer aided manufacturing (CAM), in the industry, computer has been used in monitoring several factory machines, even remotely. Several computerized robots and software controlled diagnostic tools aid in car manufacture and repair. Many thanks to artificial intelligence and expert systems which are sub-disciplines of computer science. 15. Data Communication – Computer is best known in the field of communication and data storage as found in the use of several GSM machines and Smartphones of today, email facilities, internet facilities etc. 16. Data Storage – Today, single computer machine with 150 gigabyte hard disk can still be backing up data on another 250 gigabyte external hard disk, not minding the flash drives, compact and DVD disks, MP3s, Zip disks and diskettes etc without necessarily being a mainframe computer. What is not printed out of computer at any other time or day. The reprinted copies of the original documents are also original copies. All these characteristics and uses of the computer justify its vital place and role in modern times and Information and Communication Technology, ICT in general. REVISION QUESTIONS 1. Define Computer 2. State the five pentagonal qualities that uniquely define digital computer. 3. State ten unique features, uses or characteristics of computer that distinguishes it among data processing machines 4. What do you understand by logical structures of computer? References 1. Odulaja G.O.(2015) Basic Concepts in Electronic Data Processing – A Student Companion in Computer Studies; Noble Printing Press, Ijebu-Ode 4
2. Odulaja G.O. (2003), Success in Computer Studies- Book One; Polar Computer Ventures, Ijebu-Ode 3. Microsoft Encarta Premium, 2009. 4. Kelani and Akinrinmade (1998) Elements of Data Processing 5. C.S. French (2010) Complete Course Text in Computer Science
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