COS 101 Modules 1-3 (KWASU) PDF

KWASU LOGO.jpg **KWARA STATE UNIVERSITY, MALETE** **COLLEGE OF INFORMATION AND COMMUNICATION TECHNOLOGY** **DEPARTMENT OF COMPUTER SCIENCE** **COURSE TITLE: INTRODUCTION TO COMPUTING** **COURSE CODE: COS 101** **CREDIT UNIT: 3** **Table of content** **MODULE 1: INTRODUCTION TO COMPUTING\...\...

KWASU LOGO.jpg **KWARA STATE UNIVERSITY, MALETE** **COLLEGE OF INFORMATION AND COMMUNICATION TECHNOLOGY** **DEPARTMENT OF COMPUTER SCIENCE** **COURSE TITLE: INTRODUCTION TO COMPUTING** **COURSE CODE: COS 101** **CREDIT UNIT: 3** **Table of content** **MODULE 1: INTRODUCTION TO COMPUTING\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\....3** Basic Concepts................................................................................................................3-4 Brief history of computing...........................................................................................4 Classification of computers..........................................................................................5 Classification based on technology innovation.......................................................5-6 Classification based on method of data representation.......................................7 Classification based on purpose........................................................................8-9 **MODULE 2: COMPONENTS OF COMPUTER....................................................10** Computer Hardware.......................................................................................11 Difference between RAM and ROM...............................................................12-13 Diagram illustrating the major components of computer...........................14 Peripheral devices...................................................................................................15-16 Computer Software.............................................\...\...\...\...\...\...\...\...\...\...\...\...\....17 Operating systems...........................................................................................18-20 **MODULE 3: APPLICATION OF COMPUTERS**............................................................21-23 **Module1** Introduction to Computing Basic Concepts Brief history of computing Classification of computers Classification based on technology innovation Classification based on method of data representation Classification based on purpose **Basic Concepts** **1.0 Introduction** In the 21^st^ century, computers have become indispensable tools in virtually all aspects of human lives. The development of handheld computers such as personal digital assistants (PDAs), tablet computers and smart phones has helped computers to become ubiquitous. This unit presents background information about computers by defining basic computer terms, providing a brief history of modern computing, and describing the parts of a computer system. **1.1 BRIEF HISTORY OF COMPUTING** A digital computer unlike the analogue computer and hybrid computers represents data by a coded set of discrete electrical pulses. The computer system as presently structured has passed through several stages of conceptual development including: I. The invention of ABACUS (otherwise called BEAD FRAME) in china around the 7th century B.C. The ABACUS was for addition. II. The design of a logarithmic scale by the Scottish mathematician John Napier(1550-1617) in the 17^th^ century A.D III. The inventory of the slide rule 1620 by the English mathematician Edmund Gunter (1581-1626). IV. French mathematician Blaise Pascal (1624-1662) who invented a mechanical calculator in 1642. V. Sir Samuel Morland (1625-1695), an English mathematician who invented three calculating machines between 1663 and 1666 VI. German philosopher and mathematician Gottfried Leibnitz (1646-1716) who in 1671 developed a calculator for multiplication and division. VII. J.M.Jacquard a French weaver, in 1801 developed the punched cards. VIII. Charles Babbages (1792-1872) the English mathematician who is regarded as the Father of Computing.He it was who first made an attempt to design a machine different from hand calculator. His still-born machines were called "Difference Engine"(Which he started designing in 1823) and "Analytical Engine". IX. American Statistician Hermann Hollerith(1860-1929) who in the 1880s started to develop equipment and procedure for handling census data after being commissioned for the work by the United State Bureau of the census. X. British Mathematician George Boole (1815-1864) who in the late1853 published a paper entitled "An investigation of the Laws of Thought". The mathematician theories of logic and probability are founded on these laws. His algebraic theory is now widely known as "Boolean Algebra" XI. The British mathematician Alan Turing who in 1936 proposed a test for determining whether a machine can think. This lead to the theoretical concept known as "Turing machine". XII. J.W. Mauchly and J.P. Eckert, two American Engineers who in 1939 designed the ENIAC (Electronic Numerical Integrator and Calculator). XIII. Howard Aiken, American mathematician who in 1944 invented a fully automatic calculator after seven years of work XIV. M.V. Milkes, an Englishman, who in 1949 built the first stored program computer called EDSAC (Electronic Delay Storage Automatic Computer) at Cambridge University. XV. The Hungarian-born American mathematician john Von Neuman (1903-1957) and the American mathematician Herman Goldstine and A,W, Burks who in the series of historic reports written between 1946 and 1949 (inclusive) consolidated the stored program concept of computer architecture. They were responsible for laying down the design plan for the present day computers. This design plan is sometimes referred to as the Von Neumann architecture. Their work which was carried out in the Institute for Advanced Study Princeton, New jersey, USA is considered as the most important contribution to the development of modern computers XVI. The development of EDVAC (Electronic Discrete Variable Computer) **1.2 Definition of Terms** **What is computer science?** Computer science is the study of computers and computational system. **Computer**: A computer system is an automatic electronic data processing system in the sense that it collects, manipulates, distributes, facts and figures by electronic means in order to achieve a desired output. Computer can also be define as An electronic device, operating under the control of instructions stored in its own memory that can accept data (input), process the data according to specified rules, produce information (output), and store the information for future use. Functionalities of a computer: Any digital computer carries out these functions in gross terms: i. Accept data through an input device (e.g. keyboard or mouse) ii. Process the data to convert it into information iii. Display the information on an output device (e.g. visual display unit or printer) iv. Store the information for future use in a storage device (e.g. hard disc or compact disc) **Data:** Data refer to raw or unprocessed facts about a person, place or thing. Examples of data include name, age, height and profession. Data is the plural for datum. **Information:** Information is processed data or data that has been converted into useful form e.g. the result of students in an examination or the net pay of an employee. Based on the component structure of the modern computer, at least four generation of computers have up till the 1980s emerged. **1.3 CLASSIFICATION OF COMPUTERS** There are various ways by which computers are classified, the major ones are based on the following: 1. Technological innovation. 2. Manner/method of data representation. 3. Purpose of the computer. 4. Processing speed. **CLASSIFICATION BASED ON TECHNOLOGICAL INNOVATION** Classification of computers based on technological innovation involves the grouping of computers in terms of their various generations i.e. stages of computer development. These various generations of computers were triggered by the work of inquisitive researchers who took it upon themselves to correct the mistakes or laxities in their previous discoveries at one particular time or the other. Such generations of computers are as follows: **FIRST GENERATION OF COMPUTERS (mid1940s-1950s)** These are the computers that were in use in the early 1950s.The technological innovation that led this group of computers was the **Stored Program Concept**. The logic part of these computers was made of **Vacuum Tubes** while **Magnetic Drum** was used for the memory element. Because of the vacuum tubes, first generation computers were very large, expensive and consumed a lot of electricity hence generates a lot of heat. Examples of the first generation computers are EDVAC, UNIVAC and IBM700 series. **CHARACTERISTICS OF THE FIRST GENERATION COMPUTERS** As a result of the vacuum tube used in this generation of computers, the machines possess the following features: 1. They are very large in size. 2. They consume a lot of electricity, hence generates a lot of heat. 3. They are usually very expensive to maintain. 4. The memory element was made up of magnetic drum. 5. The programs were written in Machine Language.  **SECOND GENERATION OF COMPUTERS (late1950s-mid1960s)** This group of computer came about to correct or to reduce the problems of the first generation computers. The invention of **Transistor**- a solid-state conductor made this generation of computer possible. The transistors replaced the vacuum tubes as the logic circuit and because the transistor is a solid-state device, computers processing speed became faster and the system became smaller in size compare to the first generation computers was however retained. Examples of computers in this generation are UNIVAC 1107, IBM 7030 and IBM 7090 series. **CHARACTERISTICS OF THE SECOND GENERATION COMPUTERS** 1. The logic part of computers in the generation was made up of transistors. 2. The memory element i.e. the Magnetic drum was however retained. 3. The size is also reduced compared to the size of the first generation of computers. 4. They consume less electricity hence produce less heat. 5. Assembly language was used for the programming of these computers. C:\\Users\\user\\Pictures\\transistor.png **THIRD GENERATION OF COMPUTERS (mid 1960s-1970)** The technological invention that led to this generation of computers is the **Integrated Circuit(IC).** An integrated circuit consists of complex electronic circuits fabricated on a single chip not more than two millimeters long. This reduced the size of the computers. They were also faster than the computers of the previous generations. This generation of computers used cheap **Metal Oxide Semiconductor (MOS)** for their memory element. It was in this generation of computers that high-level languages were introduced. Examples of computers in this generation are PDP-11, CDC 6600, and CDC 7600 among others. **CHARACTERISTICS OF THE THIRD GENERATION COMPUTERS**. 1. The memory element was made up of Metal Oxide Semiconductors. 2. Small Scale and medium scale integrated circuit formed the logic part 3. Computers in this generation were able to process more than one task at a time (i.e. Multi- processing ability). 4. High-level language were introduced.. 5. Operating system was also introduced in this generation. 6. These computers were faster than the previous ones. 7. Keyboard is used as input device 8. Monitor and printouts are used for output Users interacted with the third generation computers through an operating system, which allowed the device to run many different applications at one time with a central program that monitored the memory. Computers for the first time became accessible to a mass audience  **FOURTH GENERATION OF COMPUTERS (1971)** The technological innovation that led to this generation of computers is the **Very Large Integrated Circuit** of the microprocessor. A microprocessor is a central processing unit fabricated on a single silicon chip. It worth nothing that the integrated circuit mentioned above is a small-scale integration compared to the very large scale integration of the microprocessor. In fact, the introduction of microprocessors marked the beginning of varieties of application software such as the word processing and desktop publishing packages. Examples of computers in this generation are IBM 3033, Burroughs B7700 and mainframes. **CHARACTERISTICS OF THE FOURTH GENERATION COMPUTERS.** 1. Microcomputers were introduced due to the small size of microprocessors. 2. Computer became faster compared to those of the previous generation. 3. High-level languages were also used for programming this generation of computers. 4. Varieties of software application into this generation of computers. C:\\Users\\user\\Pictures\\microprocessor.png **FIFTH GENERATION OF COMPUTERS** Despite the aforementioned generations of computers new innovations are constantly springing up. This makes strict classification based on technological innovations almost impossible. In fact, under such new innovation of computer it is expected that normal or present computer architectures it expected that normal or present computer architecture of **Von Neumann model** would be emphasized. Computers would be data driven. It is also hoped that **Artificial Intelligence (AI)** will play a major role especially in the area of software development. A good example of the 5^th^ generation computers are some special purpose computers like Robots find in departmental stores and other electronic machines designed for the purpose of assisting human being in business as well as house chores. **CHARACTERISTICS OF THE FIFTH GENERATION COMPUTERS** 1. Very Large Integrated Circuit is used for the logical part. 2. The software of such computers is highly characterized with Artificial Intelligence. 3. Computers in this generation perform virtually all things. The **sixth generation** of computers came into being in the late **1990s.** The architecture is based on neural networks.  **1.4 CLASSIFICATION BASED ON METHODS OF DATA PRESENTATION** Computers can also be classified according to the manner of data representation as follows: 1. Digital computers. 2. Analogue computers. 3. Hybrid computers. Digital Computers: These are computers that records data by counting in discrete variables which corresponds to ''on'' and ''off'' states of electricity. They can only be used for the purpose of arithmetic. It is highly used for addition, subtraction, division and comparison purposes. They are often used at homes, offices, factories, and shops. Digital computers. Are either general or special purpose computers. Examples are calculator and adding machines. Analogue Computers: These are computers, which records data by using physical quantities in proportion to a given amount of number. They are used mainly for measurement for example thermometer used for measuring temperature. Hybrid Computers: These are computers, which imbibed the concepts and qualities of both digital and analogue computers e.g. Microcomputers. **1.5** **CLASSIFICATION BASED ON PURPOSE** Computers can also be classified based on the nature of purpose for which they are made. These mainly consists of two; General purpose computers and Special Purpose computers. General Purpose Computers: General purpose computers are those computers which can be programmed and used for a variety of tasks. They are computers that are made for no special purpose and can be used for multiple tasks. Special Purpose Computers: Special purpose computers on the other hand are those which are specially designed for a specific reason and have programs already hardwired to suit the specific task for which they are made. Hence they are not programmable. Examples of special purpose computers include those specially made for research and navigation purposes among others. **1.6 CLASSIFICATION BASED ON PROCESSING POWER** This classification of computers is based on the processing power and the processing power is in turn based on the computer's word length. Computers in this group are as follows: 1. Mainframe computers. 2. Minicomputers. 3. Microcomputers. **Mainframe Computers**: These are the traditional large-scale computers that have many peripherals attached to them and so can be used for different purposes simultaneously. Such computers have large main memory and many backup facilities. Therefore, they are usually very large and expensive. Mainframes are normally used in research centres and educational institutions. Examples of mainframe computers include NCR 9300 and the ICL 900 series. **Mini Computers:** These are smaller in size, cost less and have less applicability. They have smaller memory size and word lengths. Examples of mini computers include PDP 11, PDP 8 and the VAX series. **Microcomputers**: Microcomputers are that which has its processor and memory chip mounted on a single board. Microcomputers are smaller and cheaper than minicomputers. However, like the traditional mainframe computers, microcomputer, can be connected to other peripheral devices like scanner, telephone lines e.t.c. **CHARACTERISTICS OF COMPUTER** Speed, accuracy, diligence, storage capability and versatility are some of the key characteristics of a computer. A brief overview of these characteristics are--- **Speed** The computer can process data very fast, at the rate of millions of instructions per second. Some calculations that would have taken hours and days to complete otherwise, can be completed in a few seconds using the computer. For example, calculation and generation of salary slips of thousands of employees of an organization, weather forecasting that requires analysis of a large amount of data related to temperature, pressure and humidity of various places, etc. **Accuracy** Computer provides a high degree of accuracy. For example, the computer can accurately give the result of division of any two numbers up to 10 decimal places. **Diligence or Consistency** When used for a longer period of time, the computer does not get tired or fatigued. It can perform long and complex calculations with the same speed and accuracy from the start till the end. **Storage** Capability Large volumes of data and information can be stored in the computer and also retrieved whenever required. A limited amount of data can be stored, temporarily, in the primary memory. Secondary storage devices like floppy disk and compact disk can store a large amount of data permanently. **Versatility** Computer is versatile in nature. It can perform different types of tasks with the same ease. At one moment you can use the computer to prepare a letter document and in the next moment you may play music or print a document. Computers have several limitations too. Computer can only perform tasks **MODULE 2** **COMPONENT OF THE COMPUTER** Computer Hardware Difference between RAM and ROM Diagram illustrating the major components of computer Peripheral devices Computer Software Operating systems **COMPONENTS OF THE COMPUTER** There are two main components of the computer. They are: 1. The hardware components. 2. The software components. **1.0 HARDWARE COMPONENTS**: Computer hardware is the collection of physical elements that constitutes a computer system. Computer hardware refers to the physical parts or components of a computer such as the monitor, mouse, keyboard, computer data storage, hard drive disk (HDD), system unit (graphic cards, sound cards, memory, motherboard and chips), etc. all of which are physical objects that can be touched. Hardware components can be further classified into various units as follows: 1. Input unit 2. System unit 3. Output unit(Visual display unit or monitor) **THE INPUT UNIT:** This refer**s** to the device through which data is sent into the Central Processing Unit(CPU) for processing. The most common input device is the keyboard and mouse. Input device is any peripheral (piece of computer hardware equipment to provide data and control signals to an information processing system such as a computer or other information appliance. Input device Translate data from form that humans understand to one that the computer can work with. However all the input devices are important in data processing. The first step in data processing is the sending of data(to be processed) into the CPU where the actual processing takes place, from the CPU, it proceeds to the main memory where it is temporarily stored to be viewed and accessed by the users through the visual display unit(i.e. the monitor). However failure to enter the data correctly yields no useful information or output in accordance to a common computer parlance " Garbage In Garbage Out (GIGO)". Example of Input Devices:- 1.Keyboard 2.Mouse(pointing device) 3\. Microphone --------------------------- -------------------------- -------------------- 4.Touch screen 5.Touch screen 6\. Webcam 7.Touchpads 8\. MIDI keyboard 9.Graphics Tablets 10.Cameras 11.Pen Input 12.Video Capture 13.Video Capture Hardware 14.Microphone 15.Trackballs 16.Barcode reader 17.Digital camera C:\\Users\\user\\Pictures\\INPUT DEVICES.png **Keyboard:** The keyboard is the most important input device on a computer. Computer keyboards have the same layout as standard typewriters. The layout is called QWERTY, because the first six letters on the top row of letters are Q, W, E, R, T and Y. in addition to typing keys, computer keyboards have arrow keys for navigation, function keys for computer-specific tasks, and a calculator-like numeric keypad. **Mouse:** A mouse is a device for controlling the movement of a pointer or cursor on the screen.It consists of a ball which is rolled on a surface. The mouse derives its name from its resemblance to a real mouse. **Joystick:** A joystick resembles a car's gear stick. Moving the stick in any direction results in a corresponding movement of an on-screen object such as a pointer. Joysticks are mostly used for playing computer games. **Digital cameras:** They are used to capture still or moving images, which can be transferred to a computer and manipulated using image or video processing software. **THE SYSTEM UNIT**: This is the central part of the computer. It comprises of the micro processor (i.e. the CPU) and the secondary storage. This is also where peripheral devices such as the mouse, scanner, and telephone etc. are connected for use when they are needed **Central Processing Unit** (CPU) otherwise called the **Microprocessor.** A CPU is brain of a computer. It is responsible for all functions and processes. Regarding computing power, the CPU is the most important element of a computer system. The CPU is comprised of three main parts : - **Arithmetic Logic Unit (ALU**): Executes all arithmetic and logical operations. Arithmetic calculations like as addition, subtraction, multiplication and division. Logical operation like compare numbers, letters, or special characters. - **Control Unit (CU**): controls and co-ordinates computer components. 1. Read the code for the next instruction to be executed. 2. Increment the program counter so it points to the next instruction. 3. Read whatever data the instruction requires from cells in memory. 4. Provide the necessary data to an ALU or register. 5. If the instruction requires an ALU or specialized hardware to complete, instruct the hardware to perform the requested operation. - **Registers :** Stores the data that is to be executed next, \"very fast storage area\". **Primary Memory:-** 1\. **RAM:** Random Access Memory (RAM) is a memory scheme within the computer system responsible for storing data on a temporary basis, so that it can be promptly accessed by the processor as and when needed. It is volatile in nature, which means that data will be erased once supply to the storage device is turned off. RAM stores data randomly and the processor accesses these data randomly from the RAM storage. RAM is considered \"random access\" because you can access any memory cell directly if you know the row and column that intersect at that cell. 2\. **ROM** (Read Only Memory): ROM is a permanent form of storage. ROM stays active regardless of whether power supply to it is turned on or off. ROM devices do not allow data stored on them to be modified. **1.1 DIFFERENCE BETWEEN RAM AND ROM** **NO** **RAM** **ROM** -------- -------------------------------------------------- --------------------------------------------------------- 1 It is volatile It is not volatile 2 It is possible to write and read from RAM It is not possible to write to it.it can only be read. 3 Instructions are alterable by the users Instructions are not alterable by the users 4 It is the word pad of the computer It is not the word pad of the computer 5 It occupies a larger position in the main memory It occupies a smaller position in the main memory  **Secondary Memory:-** Stores data and programs permanently :its retained after the power is turned off. 1\. **Hard drive (HD):** A hard disk is part of a unit, often called a \"disk drive,\" \"hard drive,\" or \"hard disk drive,\" that store and provides relatively quick access to large amounts of data on an electromagnetically charged surface or set of surfaces. Hard disks are used to store your operating system, your application programs (i.e. your word processor, games etc) and your data. They are much faster than CD-ROMs and floppy disks and can also hold much more data. 2\. **Optical Disk**: an optical disc drive (ODD) is a disk drive that uses laser light as part of the process of reading or writing data to or from optical discs. Some drives can only read from discs, but recent drives are commonly both readers and recorders, also called burners or writers. Compact discs, DVDs, and Blu-ray discs are common types of optical media which can be read and recorded by such drives. Optical drive is the generic name; drives are usually described as \"CD\" \"DVD\", or \"Bluray\", followed by \"drive\", \"writer\", etc. There are three main types of optical media: CD, DVD, and Blu-ray disc. CDs can store up to 700 megabytes (MB) of data and DVDs can store up to 8.4 GB of data. Blu-ray discs, which are the newest type of optical media, can store up to 50 GB of data. This storage capacity is a clear advantage over the floppy disk storage media (a magnetic media), which only has a capacity of 1.44 MB. 3\. **Flash Disk** :A storage module made of flash memory chips. A Flash disks have no mechanical platters or access arms, but the term \"disk\" is used because the data are accessed as if they were on a hard drive. The disk storage structure is emulated. **OUTPUT UNIT:** This refers to the channels or mediums through which processed data is displayed. An output device is any piece of computer hardware equipment used to communicate the results of data processing carried out by an information processing system (such as a computer) which converts the electronically generated information into human readable form. C:\\Users\\user\\Pictures\\OUTPUT DEVICES.png Examples of output devices: 1.Monitor 5.LCD Projection Panels ---------------------------------- ------------------------- 2.Computer Output Microfilm(COM) 6.Plotters 3\. Projector 7.Printers (all types) 4.Speaker(s) **Monitors:** The monitor is the computer's display screen. It is also known as visual display unit. The two commonly used technologies for monitors are liquid crystal display and light emitting diodes, which have replaced cathode ray tube monitors that resembled bulky old-fashioned televisions. **Printers:** A printer is a device that expresses text or illustration on paper and other media. The two most commonly used types of printers today are inkjet and laser printers. Inkjet printers work by spraying ink on papers to produce text and characters. On the other hand, laser printers pass abeam on a cylindrical drum, which collects powdered ink (toner) and transfers the toner to paper. Laser printers work in the same way as photocopiers. **Plotters:** A plotter is a device that draws pictures by moving one or more pens on paper. Plotters can be used to produce large printouts. They are typically used by engineers, architects and interior designers who require more precision than can be offered by printers. **1.2 THE MAJOR COMPONENT OF COMPUTER SYSTEM UNIT**.  **Input Unit:** Computers need to receive data and instruction in order to solve any problem. Therefore, we need to input the data and instructions into the computers. The input unit consists of one or more input devices. Keyboard is the one of the most commonly used input device. Other commonly used input devices are the Mouse, Scanner, Microphone etc. All the input devices perform the following functions. Accept the data and instructions from the outside world. Convert it to a form that the computer can understand. Supply the converted data to the computer system for further processing. **Storage Unit**: The storage unit of the computer holds data and instructions that are entered through the input unit, before they are processed. It preserves the intermediate and final results before these are sent to the output devices. It also saves the data for the later use. The various storage devices of a computer system are divided into two categories. a\) **Primary Storage:** Stores and provides very fast. This memory is generally used to hold the program being currently executed in the computer, the data being received from the 2 input unit, the intermediate and final results of the program. The primary memory is temporary in nature. The data is lost, when the computer is switched off. In order to store the data permanently, the data has to be transferred to the secondary memory. The cost of the primary storage is more compared to the secondary storage. Therefore, most computers have limited primary storage capacity. b\) **Secondary Storage:** Secondary storage is used like an archive. It stores several programs, documents, data bases etc. The programs that you run on the computer are first transferred to the primary memory before it is actually run. Whenever the results are saved, again they get stored in the secondary memory. The secondary memory is slower and cheaper than the primary memory. Some of the commonly used secondary memory devices are Hard disk, CD, etc., **Memory Size**: All digital computers use the binary system, i.e. 0's and 1's. Each character or a number is represented by an 8-bit code. The set of 8 bits is called a byte. A character occupies 1-byte space. A numeric occupies 2-byte space. Byte is the space occupied in the memory. The size of the primary storage is specified in KB (Kilobytes) or MB (Megabyte). One KB is equal to 1024 bytes and one MB is equal to 1000KB. The size of the primary storage in a typical PC usually starts at 16MB. PCs having 32 MB, 48MB, 128 MB, 256MB memory are quite common. **Output Unit**: The output unit of a computer provides the information and results of a computation to outside world. Printers, Visual Display Unit (VDU) are the commonly used output devices. Other commonly used output devices are Speaker, Headphone, Projector etc. **Arithmetic Logical Unit**: All calculations are performed in the Arithmetic Logic Unit (ALU) of the computer. It also does comparison and takes decision. The ALU can perform basic operations such as addition, subtraction, multiplication, division, e.t.c and does logic operations viz, \>, **1.3 PERIPERAL DEVICES** They are devices attached to the system to help perform one given task or the other. They can be classified as input devices, output devices or storage devices like tape units. Peripheral input devices are those that are used to read or pass instructions to the computer Examples of peripheral input devices includes card reader, mouse, joystick etc. Peripheral output devices are those that are used to receive the result of processed data from the Central Processing unit (CPU)e.g. printer ,graph plotter etc. Peripheral storage devices are those devices used to store or back up useful information. Such devices can also be used to save work for future use. E.g. diskettes ,flash drive and memory cards. **PRINTER** This peripheral output device attached to the central processing unit (CPU)to print out processed information. TYPES OF PRINTERS - Dot Matrix Printers(DMP) - Daisywheel Printer(DP) - Laser jet Printer (LP). **Dot Matrix Printers (DMP):** These are the most popular and cheapest printer. They form each by a combination of dots usually in a pattern of 8rows by 11 columns. While 7rows by 9 columns are used for the characters, the remaining 1 row and 2 columns are used for spacing between characters. They are fast, versatile, economical and multi-purpose printers e.g. EPSON FX 1050. They can print graphics, spreadsheet charts and different types of fonts or characters that are not necessarily as sharp as those of electronic typewriters. **Daisywheel Printer (DP):** These adopt a thimble shaped printing element called Daisywheel to generate Letter Quality (LQ) **Laser jet Printer (LP**): These are high revolution printers that produce typeset quality texts and graphics.They are essentially based on the same technology as photocopy machines. They are high quality printers and give high density to produce per inch. E.g. 300 0r 600 per inch. However, the most recently designed printers are the inkjet and heat sensitive printers **TAPEUNIT** This is also a peripheral storage device designed to provide cheap and reliable back up for vital information. This is because hard disk a prone to corruption or damage particularly by power surges. Hence it provides a very convenient remedy to backup large volumes of information e.g. diskettes. **KEYBOARD** This is one of the unit devices used to send data into the system. There are two types of keyboard. They are: 1. Standard keyboard 2. Enhanced keyboard **1. 4 Introduction to Computer Software** **Introduction** Unlike hardware which refers to the physical parts of the computer that can be touched, software is the set of intangible instructions that tell the computer what to do. This unit discusses the two major categories of computer software, namely application and system software, as well as the types of software in each category. **Categories of Computer Software** Software is broadly divided into two categories: **System Software:** These are the software that interact with the computer at a very basic level. They help the computer to carry out its basic operating functions such as managing files, interacting with input/output devices, and removing viruses from the computer. Examples of system software are operating systems, utilities and language translators. **Application Software:** These are the software that help users to do real work such as creating documents, editing photos or tracking finances. Application software do not interact with the computer directly. Rather, they do so through system software such as operating systems and utilities. **Comparison Application Software and System Software** +-----------------------+-----------------------+-----------------------+ | | System Software | Application Software | +=======================+=======================+=======================+ | | Computer software, or | Application software, | | | just software is a | also known as an | | | general term | application or an | | | primarily used for | \"app\", is computer | | | digitally stored data | software designed to | | | such as computer | help the user to | | | programs and other | perform specific | | | kinds of information | tasks. | | | read and written by | | | | computers. App comes | | | | under computer | | | | software though it | | | | has a wide scope now. | | +-----------------------+-----------------------+-----------------------+ | Example: | 1\) Microsoft | 1\) Opera (Web | | | Windows | Browser) | | | | | | | 2\) Linux | 2\) Microsoft Word | | | | (Word Processing) | | | 3\) Unix | | | | | 3\) Microsoft Excel | | | 4\) Mac OSX | (Spreadsheet | | | | software) | | | 5\) DOS | | | | | 4\) MySQL (Database | | | | Software) | | | | | | | | 5)MicrosoftPowerPoint | | | | (Presentation | | | | Software) | | | | | | | | 6\) Adobe Photoshop | | | | (Graphics Software) | +-----------------------+-----------------------+-----------------------+ | Interaction: | Generally, users do | Users always interact | | | not interact with | with application | | | system software as it | software while doing | | | works in the | different activities. | | | background. | | +-----------------------+-----------------------+-----------------------+ | Dependency: | System software can | Application software | | | run independently of | cannot run without | | | the application | the presence of the | | | software. | system software. | +-----------------------+-----------------------+-----------------------+ Figure 1.0, provides an overview of application software and system software, as well as the types of software in each category. Figure 1 Overview of types of software **1.5 Operating Systems** Operating systems are the most important programs that run on a computer, because they control all activities that take place in a computer. Operating systems perform basic tasks such as keeping Strack of files, management of memory allocated to programs and data, and controlling input/output devices such as keyboard and printer. Examples of operating systems for general-purpose computers are Microsoft Windows, Mac OS, UNIX and Linux. Handheld devices use operating systems such as Windows Mobile OS, iOS and Android OS. **Utilities** A utility is a program designed to perform tasks such as optimizing a computer's performance, protecting data and facilitating communication. Examples of utility programs are: i. **Antivirus software** for protecting the computer from computer virus. ii. **Backup software** that help store copies of files, which can be restored in case the files get lost or damaged. iii. **Compression utilities (or zip software)** that shrink files so that they require less storage space. Compression utilities can also return files to their original form when required. iv. **Email software** for managing the flow of data to/from an electronic post office box. v. **Language Translators** Computers understand only machine language, in which instructions are written as strings of zeros and ones. However, programming in machine language is tedious and error-prone for humans. As a result, programs are usually written in high level languages which contain English commands and mathematical symbols that humans are familiar with. Language translators are system software that convert high level language programs to machine language programs which the computer understands. Examples of language translators are: i. **Compilers** which translate all instructions in a high level language program to machine language before executing any instruction. ii. **Interpreters** which translate and execute an instruction in a high level language program before moving to the next instruction. **Word Processors** A word processor is a program for producing documents such as letters, memos, reports and manuscripts. Word-processing software allow you to create, edit, format and spell-check documents on the screen before orienting on paper. Examples of word processors are Microsoft Word and Open Office Writer. **Spreadsheets** A spreadsheet is an arrangement of rows and columns containing values that can be manipulated. An electronic spreadsheet is a program for working with spreadsheets. Because electronic spreadsheets allow users to simple or complex formula, they can be used for performing tasks such as budgeting, tracking finances, calculating loan payments, computing student grades and estimating project costs. Electronic spreadsheets allow users to display varieties of colorful graphs. They often support *what-if-analysis*, for analyzing different scenarios such as "What if I score B's in all my courses this semester? But what if I score only C's?" examples of electronic spreadsheets are Microsoft Excel and Open Office Calc. **Database Management Systems** A database is a collection of data stored on one or more computers. A database can contain data such as details of books in a library, university student records, or bank customer details. A database management system (DBMS) is a program for storing, modifying, finding and reporting data contained in a database. DBMS allow users to *query the database*, that is, to extract information that meets certain criteria. For example, a query could request the DBMS to list all students who scored at least a B grade in COS 101, arranged according to their matriculation numbers. Examples of popular DBMS are Microsoft Access, Oracle and My SQL. **Presentation Software** Presentation software enable users to combine text, graphs, photos, sound clips and animation into series of electronic slides. For one-on-one presentations, the slides can viewed on the monitor. However, group presentations are commonly viewed using a computer projector. Presentation slides can also be posted on the Internet. Electronic slides can be used by instructors and students to deliver lecturers and oral presentations. They are also useful for presenting ideas in meetings and conferences. Examples of common presentation software are Microsoft PowerPoint and Open Office Impress and Google Presentations. **Graphics Software** Graphics software allow users to create, edit and manipulate graphics. These graphics could be pictures, images, drawings, icons or photographs. There are different types of graphics software: i. **Paint software help you paint images by providing pens, brushes and paints. They represent images using bitmap** graphics formats such as BMP, PNG, TIF and JPEG. Examples of paint software are Microsoft Paint and Corel Painter. ii. **Drawing software** are designed to for combining lines, shapes and colors into diagrams. They represent diagrams using vector graphics files such as WMF and EPS. Examples of drawing software are Adobe Illustrator and Corel DESIGNER. iii. **Photo editing software** allow you to enhance poor-quality photos by adjusting brightness and contrast, cropping out unwanted portions, and so on. A popular example of photo editing software is Adobe Photoshop. **MODULE 3** **APPLICATION OF COMPUTERS** Computers have proliferated into various areas of our lives. For a user, computer is a tool that provides the desired information, whenever needed. You may use computer to get information about the reservation of tickets (railways, airplanes and cinema halls), books in a library, medical history of a person, a place in a map, or the dictionary meaning of a word. The information may be presented to you in the form of text, images, video clips, etc. Some of the application areas of the computer are listed below--- PRACTICE QUESTIONS 1. What did first generation of computers use for circuitry? 2. What is the main technology used in third generation computers 3. Which of the following device was not invented by Babbage? a: Pascaline b: Difference Engine c: Analytical Engine 4. Which part of the computer is used for calculating and comparing? 5. The hard drive is a:Volatile b:Non --volatile c:Both d:None 6. The hardware that is responsible for processing information and processing instructions given to is a:The motherboard b:The CPU c:The hard drive d:The compact disk 7. All the following are widely used input devices except the a:Keyboard and mouse b:Microphone and scanner c:Digital camera and PC camera d:Printer and monitors 8. Which of the following is/are functions that a mouse CANNOT do? a:Scrolling b:Drag and drop c:Clicking d:Make a copy of a document 9. A joy stick is primary used to/for 10. The software can best be described as a:The team of people who used the computer b:Programmed instruction for the computer perform tasks c:Computer generated printed output d:The physical parts of a computer that cannot be seen 11. Abacus is otherwise known as 12. Who invented Mechanical calculator and which year was it 13. Who is referred to as the father of computing 14. The term GIGO is related to.......................... 15. Microsoft Word is an example of.................................. Software