Introduction to Computer Systems Learn about the most common input and output devices for the personal computer and explore the not-so-common devices used by other types of computers. input and output devices Edition 2022Prepared by: Ab Aziz Ikhwan bin AbWahab
Writer & Editor Ab Aziz Ikhwan bin Ab Wahab Jabatan Teknologi Maklumat dan Komunikasi Politeknik Kuching Sarawak KM 22, Jalan Matang, 93050, Kuching, Sarawak Tel: 082-845 596 Fax: 082-845 023 http://www.poliku.edu.my Declaration All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, electronic, mechanical, photocopying, recording or otherwise without the prior permission of the publisher. Copyright ©2022 : First Edition Copyright
Acknowledgement Alhamdulillah, praise to Allah SWT, with His grace and mercy, the First Edition of e-book Introduction to Computer System: Input and Output Devices has finally completed. We hope that this e-book will be helpful as a guideline in their learning process. This e-book is developed as a guide and reference for lecturers also. Special thanks also to those who were directly or indirectly involved in the completion of this e-book. Any positive feedback mostly welcomed and appreciated.
Abstract A computer consists of hardware and software components. Hardware is the physical equipment. It includes the case, keyboard, monitor, cables, storage drives, motherboard, and power supply. Software includes the operating system and programs. The operating system, or OS, manages computer operations such as identifying, accessing, and processing information. Programs or applications perform different functions. Programs vary widely depending on the type of information that is accessed or generated. This ebook reviews the definition of a computer, input and output devices, and the difference between input and output devices.
CONTENTS COMPUTER BASICS 2 What is Computer 3 Basic functions of Computer 5 Types of Computer INPUT DEVICES 9 Definition of Input Devices 11 Functions of Input Devices OUTPUT DEVICES 34 Definition of Output Devices 36 Functions of Output Devices 11 Examples of Input Devices 6 Computer Software 7 Computer Hardware 7 Summary 36 Examples of Output Devices DIFFERENCE BETWEEN INPUT & OUTPUT DEVICES 57 What is Input Devices 58 What is Output Devices Difference between Input and Output Devices 59 31 Review Questions 54 Review Questions 60 Summary
COMPUTER BASICS "Access to computers and the Internet has become a basic need for education in our society.” - Kent Conrad C H A P T E R 1 01
In 1640, the term ‘Computer’ was initially referred to as ‘one who calculates’. Later in 1897, it was called the ‘Calculating Machine’. In 1945, it was indicated as ‘programmable digital electronic computer’ which is now called a ‘computer’. What is Computer? Computers have become one of the most essential parts of human life. At present, computers can be easily seen in almost every sector or field even where it is most unexpected. There can be several different reasons why computers are actually required. We can summarize the reasons for the requirement of computers in three words: efficiency, accuracy, and reliability. Nowadays, computers are making jobs easier for people. Computers can be used in everything from entertainment to communication to navigation to research. That is why this era is called the era of IT (Information Technology). And now, one cannot imagine a world without computers. Therefore, it is very necessary to have knowledge of Computer basics. In this chapter, we have covered all the basics of the computer such as what is a computer, definition of computer, basic functions of a computer, types of computer etc. computer basics 02 ENIAC 1945
What is Computer definition? “A computer is a programmable electronic machine designed to take input, perform prescribed arithmetic and logical operations at fast speeds, and provide the output of these operations.” The term ‘COMPUTER’ is an acronym for ‘Common Operating Machine Purposely Used for Technological and Educational Research’. The term ‘Computer’ is derived from the Latin word ‘computare’, which is defined as- “to calculate”, “to count” or ‘to sum up”, etc. In other words, “a computer is a device that performs computation”. Basic Functions of Computer There are four basic functions of the computer: Input, Processing, Output, and Storage. 1 - Input The data is entered into the computer with the help of input devices. Like other electronic devices, a computer takes data in raw form (binary form). The user can enter the data in several formats such as the collection of letters, numbers, images, etc. The input devices convert the data in the binary form so that the computer can read the data. 03
2 - Processing The processing is the core functionality of the computer system. It is the internal process where the data is processed according to the instructions given to the computer. The data is executed sequentially and sent for further processing. The processing speed may vary in different computer systems as the speed mainly depends upon factors like which type of Motherboard, CPU (Central Processing Unit) or RAM (Random Access Memory) you are using. 3 - Output The output is the information provided by the computer after the entire processing. It is also known as the result that can be stored in the storage devices for further use. The output devices retrieve the processed data from the computer and convert the data into a humanreadable form. 4 - Storage Storage is a crucial part of the computer system. It is used to store data or instructions before and after processing. 04
Mainframe Computer M ai n f rame Comput e r s ar e smal l e r t han supe r comput e r s , s ti l l , t h e y comparati v e l y huge . T h e s e ar e not as fas t as supe r comput e r s . M ai n f rame comput e r s can s tor e huge amoun t s of data and t h e y ar e capabl e to handl e large cal culation s . Micro Computer M i c rocomput e r s ar e i n e xpe n s i v e and suppor t multi-us e r platform. M i c rocomput e r s ar e s lo w e r compar ed to supe r comput e r s and mai n f rame comput e r s . M i c rocomput e r s ar e cal l ed Pe r sonal Comput e r (PC). Mini Computer M i n i comput e r s ar e c h eape r and eas y to car r y . Not ebook and Tabl e t ar e e xampl e s of mi n i comput e r s . Super Computer Supe r comput e r s ar e large and r equi r e huge spac e for t h e i n s tal lation . T h e y ar e t h e fas t e s t and mos t e xpe n s i v e comput e r s compar ed to ot h e r s . T h e y ar e us ed for pe r formi ng huge compl e x cal culation s . Types of Computer 05
System Software System software connect the user and the hardware of the computer to interact with each other. System software provide the basic functionalities required to operate the computer system. These type of software provide an environment or platform for the other software to work on. System software run in the background. Application Software Application software are customized software designed for personal use. These type of software help users for performing basic tasks such as online research, setting an alarm, designing, or even playing games. The application software runs in the frontend and mostly used by the end-users. Therefore, these are also called ‘end-user programs’. Computer Software Computer software is a group of programming instructions designed to instruct the computer to perform specific tasks. Typically, a computer system is useless without software. There are two types of computer software, as mentioned below: 06
Computer Hardware Computer hardware are the physical components or parts that jointly form a computer system. There are different types of hardware. Depending on the structure of the computer system, hardware can be installed inside or outside of the computer physical body. The basic components of the computer hardware are listed below: • Monitor • Keyboard • Mouse • CPU (Central Processing Unit) • Motherboard • RAM (Random Access Memory) • Hard Disk Drive • Printer, etc Summary The computer plays an important role in our dayto-day life and we cannot think of life without it. While there are some disadvantages of computers, however, the advantages of computers overcome those disadvantages. Therefore, it is very important to have at least basic knowledge of computers to complete in this era of technology. 07
INPUT “The real danger is not that computers will begin to think like men, but that men will begin to think like computers.” - Sydney J Harris. C H A P T E R 2 DEVICES 08
An input device is essentially a piece of instrument or hardware that allows users to provide data, information, or control instructions to a computer used for interaction and control. Data is entered into a computer in a raw format, which is converted into computer understandable language by input devices and processed by a central processing unit (CPU) to produce output. In simple terms, an input device is a kind of peripheral device that helps communicate with processing units of the computer. Definition of Input Device Computers are essential for this technological era. They are helping people in almost every field and making life easier. We cannot think of a world without computers because they are working efficiently and with incredible speed. We cannot communicate with a computer without an input device. Although the computer can work on its own, we will neither be able to modify its settings nor add new data to the computer. This topic covers most of the input devices of a computer. Before discussing computer input devices, let's first understand the definition of an input device: input devices 09
What are Input Devices? Feeding instructions or data into a computer machine is done using hardware devices. During the process, the data is referred to as the input to a computer machine while the device or hardware device used to input the data is referred to as the input device or input unit. The input devices can be divided into different categories, such as pointing devices, keyboard devices, speech or voice input devices, draw devices, recognition devices, etc. The most common input devices of a computer system are listed below: Computer Input Devices Keyboard Mouse Joystick Scanner Trackball Microphone Webcam Touchscreen 10
Functions of Input Device Because input devices perform essential functions for computers, they are considered as parts of computer systems. They are electro-mechanical devices that help users input raw data into a computer. However, computers do not understand data in raw formats. Therefore, input devices convert raw data into the appropriate format or language that can be easily understood by a computer. The translated or converted data is stored in primary memory and sent to the CPU for further processing. In other words, the computer accepts raw input from users and translates the received input into machine language with the help of input devices. This is the primary function of the input device on the computer. Examples of Input Devices Several types of input devices are available to enter raw data into a computer. Each device has its own function, benefits, and drawbacks. The following are examples of commonly used input devices: 11
Keyboard The keyboard is one of the primary input devices, which helps in entering data and commands in a computer. The layout of the keyboard is almost identical to a traditional typewriter with additional keys that help in performing specific tasks. A normal keyboard usually has a variety of keys, such as alphabetic character keys, function keys, number keys, arrow keys, and control keys. The keyboard can be connected to a computer using USB (for a wired keyboard) or Bluetooth (for a wireless keyboard). There is no specific rule for defining the number of keys; however, most keyboards come in two sizes - 84 keys or 101/102 keys. Laptops come with inbuilt, more compact keyboards, which help make the laptop smaller and lighter. Besides, most modern devices (such as smartphones, tablets, and convertible touch screen laptops) come with on-screen virtual keyboards that help to input the data into a computer. Most English language keyboards have a QWERTY layout. 12
Mouse A mouse is the most common and very popular pointing device that helps interact with a computer through a process called 'point and click'. This is mainly used to move a cursor on the computer's screen and click on the corresponding object using its buttons (usually left, right, and middle key roller buttons). The left button helps select items while the right button helps display menus. The scroll wheel mainly helps to move the scrollbar up and down while surfing the web or reading documents. Some advanced mouse may also have additional buttons to perform specific tasks. Like the keyboard, the mouse can be both wired and wireless. The left button helps select items while the right button helps display menus. The scroll wheel mainly helps to move the scrollbar up and down while surfing the web or reading documents. Some advanced mouse may also have additional buttons to perform specific tasks. Like the keyboard, the mouse can be both wired and wireless. 13
Joystick / Gamepad Joysticks are widely used to play games on a computer. They help control the characters and vehicles of the game. It can be a standalone device or can be included with multiple buttons and triggers to add options to perform more in-game features. It can also be used as a pointing device like a mouse. Essentially, a joystick is a handle that has a spherical ball at both ends (upper and lower). It can be moved in all four directions, and its angle or moving direction is sent to the computer as data. 14
Touchpad The touchpad, also known as a trackpad, is an input device that is primarily integrated with a laptop. It is a pointing device like a surface that can detect the movements of our fingers and move the pointer accordingly. It is nothing but a common alternative to a mouse and also helps to make computer devices compact, small, and lightweight. Touchpads were introduced mainly for laptops in the year 1990. Almost all modern laptops come with a touchpad that helps to perform mouse functions. 15
Light Pen A light pen is another pointing device that has the same structure as a pen. It is a light-sensitive device consisting of a photocell and an optical system placed in a small tube. It is mainly used to select on-screen items, draw pictures, and write independently in document files using a computer screen. When the tip of the light pen is moved on the computer screen and the button on the pen is pressed, the photocell sensing element detects the screen location and sends the corresponding signal to the CPU. This helps the CPU detect pointer movements and clicks. 16
Track Ball The trackball is a pointing device that is used to perform similar tasks as a mouse. However, its mechanical structure is slightly different from that of the mouse. Unlike a mouse, the trackball does not need to be moved around the surface. Instead, the user is required to rotate a ball by turning the fingers, which moves the pointer accordingly. The ball is inserted halfway into an instrument and may contain various shapes, such as a ball, square, or button. Because the trackball does not need to be moved around the surface, it can be perfect for low-lying areas. A trackball also has buttons to perform certain functions like a mouse. Trackballs may be stand-alone devices or may be attached to a keyboard, notebook, or laptop computer instead of a mouse. 17
Scanner A scanner is an essential input device that allows us to convert a hard copy document into a digital file (.jpeg, .png, .pdf, etc.). It basically uses optical technology that reads characters or pictures from a paper and transfers them to a computer's drive for further manipulation. Like other images, the scanned image can also be saved, edited, emailed, and printed whenever we want. Scanners can be of different types, depending on the different functionality. Some common types of scanners include a photo scanner, flatbed scanner, drum scanner, sheet-fed scanner, handheld scanner, etc. 18
Graphic Tablet A graphic tablet, also known as a digitizer, is primarily used to digitally transform hand-drawn artwork (.png, .jpeg, etc.). It is an input device with a flat surface and comes with a stylus. Users can use a stylus to draw graphics on a surface like we draw something on paper using a pen or pencil. The digitizer reads the signals and converts graphics to binary input. The same drawing is displayed on a computer screen in real-time and can be saved, edited, emailed, or printed. Besides, digitizers can also be used to signatures or texts as handwritten texts or computer-typed texts. 19
Stylus A stylus is an input device used to draw or write on the surface of digitizers and touch-screens. It was mainly introduced for digitizers and PDAs; however, nowadays people are using a stylus with smartphones and tablets instead of fingers. This is because it can result in better accuracy, and prevent oil and scratches on the surface of the device from the user's fingers. 20
Touch Screen Touchscreens are widely used due to the use of portable devices, such as smartphones, notebooks, tablets, laptops, etc. Touch screens allow users to input anything from moving or copying any object. Users can perform tasks using only their fingers or stylus. A touch screen is nothing but a touch-sensitive surface or monitor screen that reads the signals of movement of the user's fingers and performs certain tasks accordingly. This can be seen nowadays in most devices, such as smartphones, cameras, GPS screens, smartwatches, laptops, etc. 21
Microphone A microphone, also known as a mic, is a type of voice input device that allows users to input voice into a computer system. Mics typically read sounds from the surroundings and convert analog sound waves into electrical signals. These signals are further converted into digital form and stored in the computer. Mics are used for many purposes, such as adding sound to a presentation, chatting while online gaming, video conferencing, voice calling, recording, voice recognition, and more. They can be of different types, depending on the quality and specific functionality. Some common types of microphones include a dynamic mic, ribbon mic, condenser mic, etc. 22
Digital Camera A digital camera is an input device that is used to capture images and video in digital form. This allows users to store the captured media files in a memory card and transfer them to the computer. Digital cameras use an image sensor chip to capture images rather than the film used by traditional cameras of the old days. Digital cameras are widely used nowadays. Many advanced digital cameras also come with a screen that displays captured media as well as allows for many other options, such as preview, zoom, delete, send, and more. 23
Webcam Webcam can capture images and videos and convert them into a digital form. A webcam is slightly different from a digital camera. Unlike digital cameras, webcams cannot operate independently. They should be connected to a computer. Also, webcams have no inbuilt memory; they use the computer's storage to save captured data. Webcams are most commonly used for video chatting and live-streaming videos. 24
Optical Character Reader (OCR) OCR is an input device used to read the handwritten or printed text and convert them to digital text. This device reads text optically, character by character, and converts the text into digital form to be stored in a computer. It is mostly used in libraries and offices to copy texts from books and save them digitally. OCR scans the documents like a scanner and then converts them into two colored bitmap versions (usually black and white). The light scanned areas are considered as background, while dark areas are considered as characters. 25
Barcode Reader A bar code reader, also known as a barcode scanner, is an input device used to read bar codes. Barcodes are data written as dark and light lines. Barcodes are usually printed on various items for labeling details. It is also known as a POS (point of sale) scanner. The bar code reader scans the bar code image using light, which is then reflected and translated into an analog signal. The signals are then decoded and transformed into alphanumeric values to be stored in a computer connected to a barcode reader. This ultimately helps in identifying product details and prices from the database. 26
QRCode Reader The QR code reader, also known as the QR code scanner, is an input device used to read QR codes. QR codes are computer-generated patterns that store or hold a modest amount of data. They do not require a database to store information separately. QR code readers are almost identical in functionalities to bar code readers. 27
Biometric Devices Biometric devices are used to input a person's scanned data based on biological characteristics, such as facial structures, fingerprints, eye corneas, etc. Most modern smartphones come with the feature of Face Unlock and Fingerprint Unlock, making them a biometric device. However, they can also be standalone devices. 28
Motion Capturing Devices These are the devices used to detect human movements and send them as input to the computer. Such devices are mostly used in advanced gaming setups, which allow players to play a game by moving their body parts accordingly. This technique is also beneficial in animation and robotics. 29
Summary This topic covers 17 examples of input devices used for computers, including their names, pictures, and functions of each. The primary function of an input device is to convert raw data given by users to machine language because computers only understand machine language and not raw input. The input device is known as the electro-mechanical component of a computer system. 30
a) Define what is input and input device. b) Explain briefly optical reader and 3 types of optical reader c) Define a trackball, a touchpad and a touch screen. d) What is a scanner? e) What is a bar code? f) What is a mouse? REVIEW QUESTIONS 31
Input is any data and instructions entered into the memory of a computer such as keyboard, touch screen and pen input An optical reader is a device that uses a light source to read characters, marks, and codes and then converts them into digital data that a computer can process. Three types of optical readers are Optical character recognition (OCR), Optical mark recognition (OMR) and Intelligent Character Recognition (ICR). A trackball is a stationary pointing device with a ball on its top or side, a touchpad is a small, flat, rectangular pointing device that is sensitive to pressure and motion and a touch screen is a touchsensitive display. A scanner is a light-sensing input device that reads printed text and graphics and then translates the results into a form the computer can process. A bar code reader pr scanner uses laser beams to read bar codes. A mouse is a pointing device that fits under the palm of your hand comfortably. a) Define what is input and input device. b) Explain briefly optical reader and 3 types of optical reader c) Define a trackball, a touchpad and a touch screen. d) What is a scanner? e) What is a bar code? f) What is a mouse? REVIEW ANSWERS 32
OUTPUT “Computing is not about computers any more. It is about living.” -Nicholas Negroponte C H A P T E R 3 DEVICES 33
Definition of Output Device An output device is essentially a piece of instrument or computer hardware that retrieves data from a computer system and further translates the received data into a form understandable to humans. The most common human-understandable forms typically include text, visual, audio, or a hard copy (printed on a paper). In simple words, an output device is a type of peripheral device that helps us to get data processed from a computer, usually in the form of audio, visual, and xerox. Computers are a necessity of today's technological era. They are making operations or tasks easier in almost every sector. We cannot even think of a world without computers because nowadays most services depend on them. The computer has a wide range of output devices, which help us to see what the computer is doing. Although computers can operate without an output device, we will not obtain the results of the processed data/ inputs from the computer. This topic discusses most of the output devices of a computer. Before discussing computer output devices, let's first understand the definition of the output device: output devices 34
What are Output Devices? Results of data fed into a computer machine are performed using specific hardware devices. During the process, the result (retrieved data) is referred to as the output from the computer machine while the devices or hardware devices used to obtain the output are referred to as the output devices. The output devices can be classified into four categories, such as visual, data, print, and sound. Depending on the type of computer and the requirements, different output devices can be attached to the computer system. The most common output devices are listed below: Computer Output Devices Monitor Inkjet Printer Speaker Headphone Projector Plotter Video Card Dot Matrix Printer 35
Functions of Output Device Since the output devices help in performing the necessary functions for the computer, they are considered as parts of the computer system. Output devices operate by receiving signals from computers and use that signal to process a task to provide output in varying forms. Examples of Input Devices Several types of output devices are available that help in obtaining output from a computer. Each device has its function, merits, and demerits. The following are examples of commonly used output devices: 36
Monitor The most common example of an output device is a monitor. It is also known as VDU (Visual Display Unit). It consists of several components, such as screens, circuitry, power supplies, screen adjustment buttons, and more, which are assembled into a casing. The monitor provides output from a computer on a screen so that users can interact with or view data digitally. The monitor typically provides output in symbolic and graphical form, generated using several small dots, known as pixels. These pixels are usually arranged in a rectangular form. That way, the monitor creates real-time video pictures and other contents with the help of a video card. The more pixels we have, the better the sharpness and quality of images. Monitors are broadly classified into two types, such as cathode-ray tubes and flat-panel displays. 37
Cathode-Ray Tube (CRT) Monitors CRT monitors use cathode ray tubes that help to produce images in the form of video signals on the screen. More clearly, the cathode ray tube generates electron beams through the electron guns, which strike the screen's inner phosphorescent surface to form the image on the screen. The monitor usually contains millions of phosphorus dots in red, green, and blue. These phosphorescent dots help to form pixels. The sharpness and clarity of the picture depend mainly on how many pixels are there and what their sizes are. The smaller the pixels, the better the picture quality of the screen. Since CRT monitors use red, green, and blue electron beams, the colors we see on the screen are a mixture of these three lights. The magnetic field helps to control the electron rays accordingly. Due to the large size and heavy power consumption, CRT monitors are currently not in widespread use. 38
Flat-Panel Displays Flat-panel displays use liquid crystal technology or plasma to generate output. In these devices, light is passed through liquid crystals to form pixels. Nowadays, most of the devices are manufactured using flat panel displays as there are significant advantages of using these displays over the traditional CRT displays. Flat-panel displays typically have lower volume, weight, and power consumption than CRT monitors. They are very light and thin and can even be hung on walls or worn on wrists. These types of displays can be found in devices such as calculators, portable video games, laptops, monitors, smartwatches, and many other digital devices. There are mainly two categories of flat-panel displays, such as a non-emissive display and an emissive display. 39
Printer The printer is another most common example of output devices that can be easily found in homes and many workplaces. The primary function of a printer is to make a copy (usually called ‘Hard copy’ or ‘Xerox copy’) or print the information on paper that is sent from the computer to the printer. The printer receives electronic data from the computer and produces a hard copy of the processed data. From compact and simple to complex and sophisticated, there are many types of printers on the market. 40
Inkjet Printers Can produce photo-realistic printouts. Fast first page out time. Typically requires minimal space. High cost per printed page. Slower at printing than laser printers. Prints out wet prints. One of the most common printing units found across Australian homes is the inkjet printer. Despite being first developed in the 1950s, inkjet printers today are still hugely popular and widely available. Due to a wide range of key advantages and very few drawbacks (other than a slightly higher cost per printed page), inkjet printing technology is as relevant today as it was over 60 years ago. Perfectly positioned for small businesses that want to produce quality over quantity printouts, inkjet printers are some of the best on the market. Inkjet Printer Advantages Inkjet Printer Disadvantages 41
Laser Printers Typically faster at printing than inkjet printers. Sharper printed text documents. Typically requires minimal space. High cost per printed page Slower at printing than laser printers Prints out wet prints. In direct contrast to inkjet printers, laser printers are best suited for organisations that need to print large volumes of documents through multiple connections. Unlike inkjet printers which are typically slower, laser printers are best known for lightning-fast printing speeds. Whereas an inkjet printer sprays microscopic drops of ink, laser printers are machines that melt toner powder onto paper to create a print. Because microscopic droplets are more accurate, this makes laser printers a weaker choice for exhibition worthy photography printing or general photoready printing. Laser Printer Advantages Laser Printer Disadvantages 42
Dot Matrix Printers Cheap initial costs. Cheap maintenance costs. Almost deprecated technology. Inferior printing quality. Very few in production. Dot matrix printers are the most popular type of impact character printer. These printers use a pattern of dots to print characters or pictures. The pattern is structured by striking a ribbon soaked in ink on paper with the help of a hammer or print head. The print head consists of several pins and structures with multiple dots in a pattern to generate the corresponding character. To print color documents, the black ribbon on these printers can be replaced with colored stripes. Generally, dot matrix printers can print 200–500 characters per second. Dot Matrix Printer Advantages Dot Matrix Printer Disadvantages 43
Touchscreen Touchscreens are output devices seen in various devices due to the use of portable devices. It is a thin, lightweight panel developed to receive output from a computer. In particular, the touch screen is a touch-sensitive surface or monitor that can display visuals or graphics. Nowadays touch screens can be easily found in modern devices, such as laptops, smartphones, tablets, etc. Because we can also use touchscreens to give input, these devices are also known as input-output devices. 44
Projector A projector is a display output device because it receives images from a computer and transfers those computer images to a wall, surface, or projection screen. Specifically, the computer first sends the signal to the video card, which then transmits the signal to the projector to project the images on the surface. Previously, projectors used lens systems that produced images by shining light through transparent lenses. Modern projectors use laser systems to directly project images using lasers. Modern projectors are also called video projectors because these projectors can also project moving images along with still images. 45