IC_Unit1-Introduction.pdf

103-IC SDJ INTERNATIONAL COLLEGE Course Code: 103 Course Title: Introduction to Computers UNIT-1: Introduction 1.1 Introd...

103-IC SDJ INTERNATIONAL COLLEGE Course Code: 103 Course Title: Introduction to Computers UNIT-1: Introduction 1.1 Introduction of Computer 1.2 Applications of Computer 1.3 Types of Computers – Super Computers, Mainframes, Mini Computers, Micro computers(Desktop, Laptop, Notebook, Tablet, Smart Phones) 1.4 Block Diagram and functional units of computer 1.1 Introduction of Computer A computer is a programmable machine designed to perform arithmetic and logical operations automatically and sequentially on the input given by the user and gives the desired output after processing. Computer components are divided into two major categories namely hardware and software. Hardware is the machine itself and its connected devices such as monitor, keyboard, mouse etc. software are the set of programs that make use of hardware for performing various functions. Generally, the term is used to describe a collection of devices that function together as a system. It performs the following three operations in sequence. 1. It receives data & instructions from the input device. 2. Process the data as per instructions. 3. Provides the result(output) in a desired form. Data :: it is the collection of raw facts, figures & symbols. Ex :: name of students and their marks in different subjects listed in random order. Information :: it is the data that is processed & presented in an organized manner. Ex:: when the names of students are arranged in alphabetical order, total and average marks are calculated & presented in a tabular form, it is information. Program :: set of instructions that enables a computer to perform a given task. Computer components 1. Hardware: 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. Prof. Ankita Sorathia Page 1 103-IC SDJ INTERNATIONAL COLLEGE 2. Software: Software is a generic term for organized collections of computer data and instructions, often broken into two major categories: system software that provides the basic task- specific functions of the computer, and application software which is used by users to accomplish specific tasks. 3. Firmware: Firmware is a software program permanently attched into a hardware device such as a keyboards, hard drive, BIOS, or video cards. It is programmed to give permanent instructions to communicate with other devices and perform functions like basic input/output tasks. Firmware is typically stored in the flash ROM (read only memory) of a hardware device. It can be erased and rewritten. Firmware was originally designed for high level software and could be changed without having to exchange the hardware for a newer device. Firmware also retains the basic instructions for hardware devices that make them operative. Without firmware, a hardware device would be non-functional. ADVANTAGES OF COMPUTERS OR CHARACTERISTICS OF COMPUTERS 1. Speed : Computers work at an incredible speed. A powerful computer is capable of performing about 3-4 million simple instructions per second. 2. Accuracy : In addition to being fast, computers are also accurate. Errors that may occ0ur can almost always be attributed to human error (inaccurate data, poorly designed system or faulty instructions/programs written by the programmer) 3. Diligence: 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. 4. 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. 5. Versatility: Computer is versatile in nature. It can perform different types of tasks with the same case. 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 that it has been programmed to do. 6. Power of Remembering : As a human being acquires new knowledge, his/her brain subconsciously selects what it feels to be important and worth retaining in memory. The brain relegates unimportant details to back of mind or just forgets Prof. Ankita Sorathia Page 2 103-IC SDJ INTERNATIONAL COLLEGE them. This is not the case with computers. A computer can store and recall any amount of information because of its secondary storage (a type of detachable memory) capability. It can retain a piece of information as long as a user desires and the user can recall the information whenever required. Even after several years, a user can recall exactly the same information that he/she had stored in the computer several years ago. A computer forgets or looses certain information only when a user asks it to do so. Hence, it is entirely up to the user to make a computer retain or forget some information. Limitations of Computers: The computer cannot think on its own, since it does not have its own brain. It can only do what is has been programmed to do. It can execute only those jobs that can be expressed as a finite set of instructions to achieve a specific goal. Each of the steps has to be clearly defined. 1. Computers need clear & complete instructions to perform a task accurately. If the instructions are not clear & complete, the computer will not produce the required result. 2. Computers cannot think. 3. Computers cannot learn by experience. EVOLUTION OF COMPUTERS OR GENERATIONS OF COMPUTERS: Basic Terms Related to Computers The basic terms related to generations of computers are listed below. 1. Vacuum Tube: Vacuum tubes have the functionality of controlling the flow of electronics in a vacuum. Generally, it is used in switches, amplifiers, radios, televisions, etc. 2. Transistor: A transistor helps in controlling the flow of electricity in devices, it works as an amplifier or a switch. 3. Integrated Circuit (IC):Integrated circuits are silicon chips that contain their circuit elements like transistors, resistors, etc. 4. Microprocessors: Microprocessors are the components that contain the CPU and its circuits and are present in the Integrated Circuit. 5. Central Processing Unit (CPU): The CPU is called the brain of the computer. CPU performs processing and operations work. Prof. Ankita Sorathia Page 3 103-IC SDJ INTERNATIONAL COLLEGE 6. Magnetic Drum: Magnetic Drum is like a cylinder that stores data and cylinder. 7. Magnetic Core: Magnetic cores are used to store information. These are arrays of small rings. 8. Machine Language: Machine Language is the language that a computer accepts (in the form of binary digits). It is also called low-level programming language. 9. Memory: Memory is used to store data, information, and program in a computer. 10. Artificial Intelligence: Artificial Intelligence deals with creating intelligent machines and behaviors. Generations of Computer Time-Period Evolving Hardware First Generation 1940s – 1950s Vacuum Tube Based Second Generation 1950s – 1960s Transistor Based Third Generation 1960s – 1970s Integrated Circuit Based Fourth Generation 1970s – Present Microprocessor Based Fifth Generation Present – Future Artificial Intelligence Based First Generation Computers The technology behind the primary generation computers was a fragile glass device, which was called a vacuum tube. These computers were very heavy and really large. These weren’t very reliable and programming on them was a tedious task as they used low-level programming language and used no OS. First-generation computers were used for calculation, storage, and control purpose. They were too bulky and large that they needed a full room and consume a lot of electricity. Each computer had a different binary coded program called a machine language that told it how to operate. The Abacus, which emerged about 5000 years ago in Asia Minor and is still in use today, allows users to make computations using a system of sliding beads arranged on a rack. Early merchants used Abacus to keep trading transactions. Prof. Ankita Sorathia Page 4 103-IC SDJ INTERNATIONAL COLLEGE Blaise Pascal, a French mathematician invented the first mechanical machine, a rectangular brass box, called Pascaline which could perform addition and subtraction on whole numbers. This was in the seventeenth century. Colmar, a Frenchman invented a machine that could perform the four basic arithmetic functions of addition, subtraction, multiplication and division. Colmar‟s mechanical calculator, “Arithmometer”, presented a more practical approach to computing. With its enhanced versatility, the “Arithmometer” was widely used until the First World War, although later inventors refined Colmar‟s calculator, together with fellow inventors, Pascal and Leibniz, he helped define the age of mechanical computation. Charles Babbage a British mathematician at Cambridge University invented the first analytical engine or difference engine. This machine could be programmed by instructions coded on punch cards and had mechanical memory to store the results. For his contributions in this field Charles Babbage is known as the “father of modern digital computer”. Examples of some main first-generation computers are mentioned below.  Mark I – This was the first fully automatic calculating machine. It was designed by Howard Aiken of Harvard University in collaboration with IBM. This machine was an electronic relay computer. Electromagnetic signals were used for the movement of mechanical parts. Mark I could perform the basic arithmetic and complex equations. Although this machine was extremely reliable, it was very slow (it took about 3-5 seconds per calculation) and was complex in design and large in size.  Atanasoff-Berry Computer (ABC) – This computer developed by John Atanasoff and Clifford Berry was the world’s first general purpose electronic digital computer. It made use of vacuum tubes for internal logic and capacitors for storage  ENIAC: Electronic Numerical Integrator and Computer, built by J. Presper Eckert and John V. Mauchly was a general-purpose computer. It had been cumbersome, and large, and contained 18,000 vacuum tubes.  EDVAC: Electronic Discrete Variable Automatic Computer was designed by von Neumann. It could store data also as instruction and thus the speed was enhanced.  UNIVAC: Universal Automatic Computer was developed in 1952 by Eckert and Mauchly. Prof. Ankita Sorathia Page 5 103-IC SDJ INTERNATIONAL COLLEGE Vacuum Tube Characteristics of First-Generation Computers Characteristics Components Main electronic Vacuum tube. component Programming language Machine language. Main memory Magnetic tapes and magnetic drums. Input/output devices Paper tape and punched cards. Very slow and very large (often taking up Speed and size an entire room). Examples of the first IBM 650, IBM 701, ENIAC, UNIVAC1, generation etc. Second Generation Computers Second-generation computers used the technology of transistors rather than bulky vacuum tubes. Another feature was the core storage. A transistor may be a device composed of semiconductor material that amplifies a sign or opens or closes a circuit. Transistors were invented in Bell Labs. The use of transistors made it possible to perform powerfully and with due speed. It reduced the dimensions and price and thankfully the warmth too, which was generated by vacuum tubes. Central Processing Unit (CPU), memory, programming language, and input, and output units also came into the force within the second generation. The machine language was replaced by assembly language. Thus the long and difficult Prof. Ankita Sorathia Page 6 103-IC SDJ INTERNATIONAL COLLEGE binary code was replaced with abbreviated programming code which was relatively easy to understand. The programming language was shifted from high level to programming language and made programming comparatively a simple task for programmers. Languages used for programming during this era were FORTRAN (1956), ALGOL (1958), and COBOL (1959). Transistor Characteristics of Second-Generation Computers Characteristics Components Main electronic component Transistor. Programming language Machine language and assembly language. Memory Magnetic core and magnetic tape/disk. Input/output devices Magnetic tape and punched cards. Smaller in size, had low power consumption, and Power and size generated less heat (in comparison with the first- generation computers). Examples of the second PDP-8, IBM1400 series, IBM 7090 and 7094, generation UNIVAC 1107, CDC 3600, etc. Third Generation Computers During the third generation, technology envisaged a shift from huge transistors to integrated circuits, also referred to as IC. Here a variety of transistors were placed on silicon chips, called semiconductors. The most feature of this era’s computer was speed and reliability. IC was made from silicon and also called silicon chips. Prof. Ankita Sorathia Page 7 103-IC SDJ INTERNATIONAL COLLEGE A single IC has many transistors, registers, and capacitors built on one thin slice of silicon. The value size was reduced and memory space and dealing efficiency were increased during this generation. Programming was now wiped out Higher level languages like BASIC (Beginners All-purpose Symbolic Instruction Code). Minicomputers find their shape during this era. Integrated Circuit Characteristics of Third-Generation Computers Characteristics Components Main electronic Integrated circuits (ICs). component Programming language High-level language. Memory Large magnetic core, magnetic tape/disk. Magnetic tape, monitor, keyboard, printer, Input/output devices etc. Examples of the third IBM 360, IBM 370, PDP-11, NCR 395, generation B6500, UNIVAC 1108, etc. Fourth Generation Computers The Fourth Generation realized Large Scale Integration (LSI) which could fit hundreds of components on one chip and Very Large Scale integration (VLSI) which squeezed thousand of components on one chip. In 1971 First microprocessors were used, the large-scale of integration LSI circuits built on one chip called microprocessors. The advantage of this technology is that one microprocessor can contain all the circuits required to perform arithmetic, logic, and control functions on one chip. The computers using microchips were called microcomputers. This generation provided even smaller size of computers, with larger capacities. That’s not enough, then Very Large Scale Integrated (VLSI) circuits replaced LSI circuits. The Intel 4004 chip, developed in 1971, located all the components Prof. Ankita Sorathia Page 8 103-IC SDJ INTERNATIONAL COLLEGE of the pc from the central processing unit and memory to input/ output controls on one chip and allowed the dimensions to reduce drastically. Technologies like multiprocessing, multiprogramming, time-sharing, operating speed, and virtual memory made it a more user-friendly and customary device. The concept of private computers and computer networks came into being within the fourth generation. Microprocessor Characteristics of Fourth-Generation Computers Characteristics Components Very-large-scale integration (VLSI) and the Main electronic microprocessor (VLSI has thousands of transistors on a component single microchip). Memory semiconductor memory (such as RAM, ROM, etc.). Input/output pointing devices, optical scanning, keyboard, monitor, devices printer, etc. Examples of the IBM PC, STAR 1000, APPLE II, Apple Macintosh, Alter fourth generation 8800, etc. Fifth Generation Computers The technology behind the fifth generation of computers is AI. It allows computers to behave like humans. It is often seen in programs like voice recognition, area of medicine, and entertainment. Within the field of game playing also it’s shown remarkable performance where computers are capable of beating human competitors. The speed is the highest, size is the smallest and area of use has remarkably increased within the fifth generation computers. Though not a hundred percent AI has been achieved to date but keeping in sight the present developments, it is often said that this dream also will become a reality very soon. Prof. Ankita Sorathia Page 9 103-IC SDJ INTERNATIONAL COLLEGE To summarize the features of varied generations of computers, it is often said that a big improvement has been seen so far AI-Based Computers Characteristics of Fifth-Generation Computers Characteristics Components Based on artificial intelligence, uses the Ultra Large-Scale Main Integration (ULSI) technology and parallel processing method electronic (ULSI has millions of transistors on a single microchip and the component Parallel processing method use two or more microprocessors to run tasks simultaneously). Language Understand natural language (human language). Size Portable and small in size. Trackpad (or touchpad), touchscreen, pen, speech input Input/output (recognize voice/speech), light scanner, printer, keyboard, device monitor, mouse, etc. Example of the fifth Desktops, laptops, tablets, smartphones, etc. generation 1.2 Application of computer Computers play a role in every field of life. They are used in Home Computers are used at homes for several purposes like online bill payment, watching movies or shows at home, home tutoring, social media access, playing games, internet access, etc. They provide communication through electronic mail. They help to avail work from home facility for corporate employees. Computers help the student community to avail online educational support. Prof. Ankita Sorathia Page 10 103-IC SDJ INTERNATIONAL COLLEGE Medical Field Computers are used in hospitals to maintain a database of patients’ history, diagnosis, X- rays, live monitoring of patients, etc. Surgeons nowadays use robotic surgical devices to perform delicate operations, and conduct surgeries remotely. Virtual reality technologies are also used for training purposes. It also helps to monitor the fetus inside the mother’s womb. Entertainment Computers help to watch movies online, play games online; act as a virtual entertainer in playing games, listening to music, etc. MIDI instruments greatly help people in the entertainment industry in recording music with artificial instruments. Videos can be fed from computers to full screen televisions. Photo editors are available with fabulous features. Industry Computers are used to perform several tasks in industries like managing inventory, designing purpose, creating virtual sample products, interior designing, video conferencing, etc. Online marketing has seen a great revolution in its ability to sell various products to inaccessible corners like interior or rural areas. Stock markets have seen phenomenal participation from different levels of people through the use of computers. Education Computers are used in education sector through online classes, online examinations, referring e-books, online tutoring, etc. They help in increased use of audio-visual aids in the education field. Government In government sectors, computers are used in data processing, maintaining a database of citizens and supporting a paperless environment. The country’s defense organizations have greatly benefitted from computers in their use for missile development, satellites, rocket launches, etc. Banking In the banking sector, computers are used to store details of customers and conduct transactions, such as withdrawal and deposit of money through ATMs. Banks have reduced manual errors and expenses to a great extent through extensive use of computers. Business Nowadays, computers are totally integrated into business. The main objective of business is transaction processing, which involves transactions with suppliers, employees or customers. Computers can make these transactions easy and accurate. People can analyze investments, sales, expenses, markets and other aspects of business using computers. Training Prof. Ankita Sorathia Page 11 103-IC SDJ INTERNATIONAL COLLEGE Many organizations use computer-based training to train their employees, to save money and improve performance. Video conferencing through computers allows saving of time and travelling costs by being able to connect people in various locations. Arts Computers are extensively used in dance, photography, arts and culture. The fluid movement of dance can be shown live via animation. Photos can be digitized using computers. Science and Engineering Computers with high performance are used to stimulate dynamic process in Science and Engineering. Supercomputers have numerous applications in area of Research and Development (R&D). Topographic images can be created through computers. Scientists use computers to plot and analyze data to have a better understanding of earthquakes. 1.3 CLASSIFICATION OF COMPUTERS Computers are broadly classified into two categories depending upon the logic used in their design as (Processing ability – according to purpose, data handling, and functionality) Classification Of Computer and Types Of Computer According To Data Representation (Data 1. Digital handling) 2. Analog 3. Hybrid According To Purpose 1. General Purpose 2. Specific Purpose Types Of Computer According To Use 1. Scientific 2. Business Classification Of Computer According 1. Micro To Size (Functionality) 2. Mini 3. Mainframe 4. Super Classification of Computers – Based Data Handling: The computer is further classified into three types based on its ability to handle data or how it processes incoming data differently. They are 1. Digital computer 2. Analog computer 3. Hybrid computer Prof. Ankita Sorathia Page 12 103-IC SDJ INTERNATIONAL COLLEGE 1. Digital Computer: A digital computer deals with the data that can be stored in binary format i.e. in the form of 0s and 1s. This computer stores data or information as voltage pulses that either indicate 0 or 1. Before being stored in a computer’s memory, all types of data, including text documents, music files, and graphic images, are transformed into binary format. It is a machine that manipulates discrete data and executes logical and mathematical operations. 2. Analog Computer: An Analog computer is used to process the analog data. Analog data is data that is constantly changing or varying. They are used to measure continuously varying aspects of physical quantities such as electrical current, voltages, hydraulic pressure, and other electrical and mechanical properties. Analog computer does not measure discrete values. They are employed in scientific and industrial applications. 3. Hybrid Computer: A hybrid computer is a combination of both a digital computer system and an analog. The hybrid computer has the capacity to handle both analog and digital input. While the digital half of the system manages the numerical and logical operation, the analog portion of the system handle the continuously varying aspects of complex mathematical computation. The system’s controller is also a part of the digital component. Hybrid computers are used in medical science to measure the heartbeat of the patient, also used in controlling industrial processes and scientific applications. Classification of Computers – Based on Purpose: Computers are broadly classified into two types based on its purpose: 1. General-purpose computer 2. Specific-purpose computer 1. General Purpose Computer: A general-purpose computer is built to do a variety of common tasks. Computers of this type have the ability to store multiple programs. They can be applied in the workplace, in science, in education, and even at home. Such computers are adaptable, but they are also less effective and move more slowly. 2. Specific Purpose Computer: A single specific task can be handled by a specific-purpose computer, which is designed to execute a certain task. They aren’t made to manage several programs. They were therefore not adaptable. Since they are made to handle a specific task, they are more efficient and faster than general-purpose computers. These computers are utilized for things like airline reservations, air traffic control, and satellite tracking. Classification of Computers – Based on their Functionality and Sizes: Prof. Ankita Sorathia Page 13 103-IC SDJ INTERNATIONAL COLLEGE Computers are categorized into four groups according to their external dimensions, internal capabilities, and external uses. Here is list of computers classified based on functionality: 1. Supercomputer 2. Mainframe computer 3. Minicomputer 4. Microcomputer 1. Supercomputer: Among digital computers, supercomputers are the biggest, fastest, strongest, and priciest. The first supercomputer was created in the 1960s for the American Department of Defense (USA). Supercomputers use several processors to increase their speed, and many people can use them simultaneously. Supercomputers are generally utilized for scientific purposes and large-scale, complex calculations. They are widely used in the aerospace, automotive, chemical, electronics, and petroleum industries, as well as for weather forecasting and seismic analysis. Example for supercomputer Jaguar, Nebulae, Roadrunner 2. Mainframe Computer: Mainframe computers, also known as mainframes, are the most commonly used type of digital computer in large industries for controlling processes as well as in offices for maintaining networks and providing access to shared resources. IBM is estimated to control two-thirds of the mainframe market. They are far more suitable for intensive operation than supercomputers. Many modern computers can multitask; however, they are typically limited to eight or fewer processors. Megaflops (millions of floating-point arithmetic operations per second) are used to measure processor speed. Mainframe computer systems are powerful enough to support a hundred users at remote terminals at the same time. It can support hundreds of users by keeping multiple programs in primary memory and switching between them quickly. Multi-programming refers to the ability to run multiple programs at the same time for multiple users. Example for Mainframe computer IBM-3000 series, IBM 4300, IBM 3090. Prof. Ankita Sorathia Page 14 103-IC SDJ INTERNATIONAL COLLEGE 3. Mini Computer: Most minicomputers, like mainframes, are multiuser and general-purpose computers. The primary distinction between mainframes and minicomputers is that minicomputers are slower even when performing the same tasks as mainframes. Example for Mini computer PDP series 4. Micro Computer: The most common type of computer, widely used in homes, schools, banks, and offices, among other places. It is a low-cost digital computer with a single microprocessor, storage unit, and input/output device. Microcomputers are typically designed for individual use only. They were originally referred to as microcomputers because they were so small in size compared to supercomputers and mainframes. They are commonly used in homes, offices, and for personal use, so they are also referred to as personal computers. Example for Micro computer Desktop computers and portable computers like a laptop, personal digital assistant (PDA)  Desktop Computer: A desktop computer, also known as a PC (Personal computer), is the most common type of microcomputer. It have CPU (Central Processing Unit), a keyboard and a mouse for input, and a monitor or display unit for output. The CPU is made up of a microprocessor, main memory, secondary storage unit such as a hard drive or optical drive, and a power supply unit all housed in a single cabinet. Example for Desktop computer Apple, Dell, Hp, Lenovo.  Portable Computer: Portable computers, such as laptops and PDAs, have surpassed desktop computers in popularity. The best feature of this portable computer is that it is Prof. Ankita Sorathia Page 15 103-IC SDJ INTERNATIONAL COLLEGE lightweight and portable. Laptops have all of the same components as desktop computers, but they are more compact and smaller in size. A palm-sized portable digital assistant (PDA) is another type of portable computer. As a result, it is also known as a palmtop computer. PDAs are used to keep track of appointments, take important notes, set reminders, perform mathematical calculations, play games, and even surf the internet and send emails. In 1993, Apple released the Newton, the first personal digital assistant. Example for Portable computer Palm Pilot, Handspring Visor, HP Jordana, Compaq Aero, Franklyn eBook man 1.4 BASIC COMPONENTS OF A COMPUTER SYSTEM OR BLOCK DIAGRAM OF COMPUTER Input Unit Input unit is used for transfers’ raw Data and control signals into the information processing system by the user before processing and computation. All the input unit devices provide the instructions and data are transformed into binary codes that is the primary memory acceptable format. Example of Input unit devices: keyboard, mouse, scanner, joystick, MICR, Punched cards, Punched paper tape, Magnetic tape etc. Memory or Storage Unit Memory or Storage unit is used for storing Data during before and after processing. The capacity of storage is expressed in terms of Bytes. The two terms Memory or Storage unit are used interchangeably, so it is important to understand what is the difference between memory and storage? Prof. Ankita Sorathia Page 16 103-IC SDJ INTERNATIONAL COLLEGE Memory This unit retains temporarily results till further processing, For example, Random Access Memory (RAM).This memory is volatile, which means data is disappears when the power is lost. Storage The storage or “secondary storage” is used for retain digital data after processing for permanently. For example hard drive. The Storage is non-volatile in nature. CPU does not access directly to secondary storage memories, instead they accessed via input-output unit. The contents of secondary storage memories are first transferred to the main memory (RAM) and then CPU access it. Central Processing Unit The main chip in a computer is the microprocessor chip, which is also known as the CPU (central processing unit). The CPU is mounted on a printed circuit board called the main board or mother board. This chip is considered to be the controlling chip of a computer system since it controls the activities of other chips as well as outside devices connected to the computer, such as monitor and printer. In addition, it can also perform logical and computational tasks. Microprocessors work on a parallel system. The various activities that a microprocessor performs, such as storing data, doing arithmetic calculations (addition, subtraction, multiplication, division, etc.), are the result of instructions given to the CPU in the form of sequences of 0s and 1s. Microprocessors are designed to carry out a large number of instructions and all the instructions may be represented by different sequences of 0s and 1s. Each instruction is represented by a unique set of 0s and 1s. Arithmetic logic unit (ALU) Arithmetic Logical Unit is used for processing data after inputting data is stored into primary unit. The major operations of Arithmetic Logical Unit are addition, subtraction, multiplication, division, logic and comparison. Control unit (CU) It is like a supervisor, that checks ordaining operations or check sequence in which instructions are executed. Output Unit Output Unit receives information from the CPU and then delivers it the external storage or device in the soft or hard processed form. The devices which are used to display output to the user are called output devices. The Monitor or printer is common output device. Prof. Ankita Sorathia Page 17