Introduction to Computers

Introduction to Computers

• The word "computer" comes from "to compute," meaning to calculate.
• Computers are calculation devices that perform arithmetic operations quickly.
• A computer is a device that operates upon data in the form of numbers, letters, and symbols of various sizes.
• Computers store, process, and retrieve data as needed.
• Computers are called "Data Processors" because processing data is fundamental to their operation.
• A computer first receives data, processes it, and then produces information.
• A computer is an electronic device that receives input from a user, processes it, and gives output according to the user's requirements.
• A computer's main tasks are input, processing, and output.

Computer Characteristics

• Computers are automatic machines that work without human intervention.
• Once started, they continue a job until finished.
• Computers cannot start themselves; they need to be told what to do and in what sequence.
• Computers cannot make decisions on their own and have no feelings.
• The accuracy of computers is very high, depending on their design.
• Errors in computing are typically due to human error or incorrect data, not technological faults.
• Computers can do a lot of work in a few seconds vs humans which can take an entire year
• Computer speed is measured in microseconds, and powerful computers can perform billions of arithmetic operations per second.
• Computers are diligent and can work continuously for hours without errors or fatigue.
• They perform calculations with the same accuracy and speed every time.
• Versatility is a key feature, allowing computers to switch between tasks like preparing exam results or electricity bills.
• Computers store and recall vast amounts of data in their storage devices.
• Information is retained as long as desired and recalled when required, maintaining accuracy over time
• Computers are not magical devices and lack intelligence.
• I.Q. (Intelligence Quotient) of computers are zero.

Data Processing Cycle

• Data Processing refers to any process where a computer program enters, summarizes, analyzes, or converts data into usable information.
• Data processing involves recording, analyzing, storing, summarizing, and storing data and can be automated and run on a computer.
• Data processing includes all activities common to data processing systems, whether manual or electronic.
• The data processing cycle includes activities grouped into data input, data processing, data output, and storage.
• The main aim of the data processing cycle is to convert data into meaningful information.
• Data processing systems are often referred to as Information Systems.
• Information Systems typically take raw Data as Input to produce Information as Output.
• The data processing cycle contains the main four functions: data input, data process, data storage, and data output.
• Data input refers to activities required to record data, and involves entering data into the computer system
• The input data context must be checked or verified.
• Data processing includes classifying, storing, calculating, comparing, or summarizing data, and converts data into meaningful information via the use of techniques.
• Data output is a communication function that transmits information to the outside world, converts data into meaningful formats, and sometimes includes decoding activities.
• Data storage involves preserving data and information for future use

Computer Classification

• Computers are divided into analog, digital, and hybrid types based on data processing.
• Analog Computers represent data as continuously varying voltage and operate by measuring rather than counting.
• Analog computers produce estimated and not exactly repeatable results due to continuously variable data.
• Analog computers can perform multiple tasks simultaneously and work with irrational numbers effectively.
• Voltage, temperature, and pressure are measured using analog devices like voltmeters, thermometers, and barometers.
• Digital Computers are based on digital technology and represent information by numerical digits.
• Digital computers data are represented as discrete units of electrical pulses, measured in 'on' or 'off' states.
• Digital computers results are accurate
• Hybrid Computers combine features of both analog and digital computers Hybrid computers has the speed of analog and the accuracy of digital.
• Hybrid computers accept data in analog form and present digital output.
• Hybrid computers process data digitally, and require analog-to-digital and digital-to-analog converters for output.
• Computers are classified into micro, mini, mainframe, and supercomputers based on data processing capabilities:
• Microcomputers use a microprocessor chip as their central processing unit and began in the late 1970s.
• The first microcomputer had an 8-bit processor.
• Microcomputers are known as personal computers, designed for individual use and can be PCs, workstations, or notebooks.
• They are small, affordable, and examples include IBM PC, IBM PC/XT, and IBM PC/AT.
• Minicomputers originated in the 1960s performing limited tasks
• Minicomputers are less expensive and lower than mainframe computers in processing capabilities
• Minicomputers support 10 to 100 users simultaneously.
• Minicomputers of the 1970s had 8-bit or 12-bit processors, and architecture grew to 16 and 32 bits, leading to supermini computers like IBM AS400.
• Mainframe Computers are powerful and can support thousands of users simultaneously.
• Mainframe computers contain powerful data processing systems, and can run multiple operating systems.
• Mainframe computers are capable of processing 100 million instructions per second
• Mainframe computers are large, expensive computers possess large internal storage capacity and high processing speed.
• They are used in organizations needing to process large online transactions, requiring massive storage and processing.
• Mainframe computer systems are centrally housed with user terminals connected to them and needs humidity & temperature controls
• IBM and DEC are major vendors of mainframes.
• MEDHA, SPERRY, IBM, DEC, HP, and HCL are brands of mainframe
• Super Computers are the the most powerful and expensive computers.
• Super Computers do complex scientific applications requiring huge processing power.
• Super Computers calculate very speedy due to the use of multiprocessor technology.
• Super Computers are special purpose computers designed to perform specific tasks.
• The cost of supercomputers depends on processing capabilities and configuration.
• The speed of modern computers is measured in gigaflops, teraflops, and petaflops.
• One gigaflop = 10^9 arithmetic operations/second, one teraflop = 10^12 arithmetic operations/second, one petaflop = 10^15 arithmetic operations/second
• PARAM, EKA, and BLUE GENE/P are examples of supercomputers.

Computer Generations

• "Generation" in Computing refers to a set of Technology that provides a framework for Computer Technology growth
• The First Generation of computers lasted from 1942-1955, and used vacuum tube technology as a calculating device. -- First Generation of computers performed calculations in milliseconds and were bulky, complex in design, and required large rooms. -- First Generation of computers generated a lot of heat, and required constant hardware maintenance, along with air-conditioned rooms. -- First Generation of computers commercial production of machines was difficult, costly, and difficult to configure, and they had limited commercial use. ENIAC, EDVAC and EDSAC are examples.
• The Second Generation of computers lasted from 1955-1964 and used transistor technology. -- Second Generation systems were ten times smaller with less heat and power consumption than first-generation computers. -- Second Generation computers performed calculations in microseconds, required air conditioning, and were easier to configure. -- The Third Generation of computers lasted from 1965-1975 and used IC (Integrated Circuit) chip technology -- Third Generation computer are smaller in size with faster calculations than previous generations. -- Third Generation has large, fast primary/secondary storage, required air conditioning, and were widely used for commercial applications. -- Third Generation has general-purpose computers programmed with high-level languages like COBOL and FORTRAN, that consume less power and generate less heat than 2nd generation computers.
• Fourth Generation computers are from 1975-1989. -- Fourth Generation computers have Microprocessor chip technology based on LSI & VLSI microprocessor chip and is smaller, faster, and requires less maintenance than previous generations. -- Fourth Generation computers are very reliable, easy to configure, and allows for network connectivity with no air conditioning and is the the cheapest in price.
• The Fifth Generation of computers cover from 1989 to present and uses ULSI microprocessor chip technology. -- Fifth Generation are smaller, handier, and based on ULSI chips with 100 million electronic components. -- Fifth Generation speed is increased, it consumes less power, air-conditioner is not required, has a user friendly interface, and allows writing programs with high level languages. -- Notebook computers are example of this generation

Computer Block Diagram

• A simple computer system comprises Input Devices, CPU (Central Processing Unit), and Output Devices.
• Input Devices which enter data into the computer system, are keyboards, mice, scanners, and light pens.
• Input Devices receives data from the outside and converts it for computer processing, then send the data to CPU.
• Output Devices display results generated by computer such as monitor, printer, plotter, and speakers.
• Input Devices receive the the result from the CPU and converts it into human readable form
• Memory Unit stores data and instructions for processing before the start of processing, and also stores the result before it is sent to output devices.
• Arithmetic & Logical Unit (ALU) is where data/instructions are processed, calculations/comparisons are made, and arithmetical/logical operations is performed. -- Arithmetic operations includes addition, subtraction, multiplication, and division, and operations contains comparison such as less than.
• The Control Unit controls the movement of data/program instructions into/out of CPU and the operations of ALU.
• • The Control Unit's main function is to manage activities within the computer system, controls both internal/external parts which is also the Central Processing Unit.
• • The CPU contains Control Unit and Arithmetic & Logic Unit.

Input Devices

• Input devices enter data into the computer system, examples are keyboard, mouse, and scanner with functions include accepting data from the outside world and translating it in the CPU
• Standard input devices are keyboards, pointing devices are the mouse, and special input devices are the microphone.

Keyboard

• A Keyboard is the most commonly used input device, similar to a typewriter with keys for alphabets, numbers, and special signs.
• Types of keyboards: general and special keys
• Standard keyboards are used in personal computers with enough keys for applications
• General purpose keyboard contains 101 keys, and is divided into: -- Alphanumeric keypad, centered in the keyboard, contains alphabets, numbers, and special signs. -- Numeric keypad, on the right side, includes numbers 0 to 9 and mathematical signs -- Arrow keys moves cursor left, right, up, and down. -- Function keys are the first line of keyboard, and generates shortcuts -- Special keys performs specific task. There are TAB, ENTER, SPACE, BACKSPACE, DELETE, HOME, END, PAGE UP, PAGE DOWN, PRINT SCREEN, and INSERT keys. -- ESC negate commands, ALT expands functionality, CTRL expands functionality, NUMLOCK enables numeric keypad, and CAPSLOCK types all inputted text capitally.
• Special purpose keyboards are used for faster data entry and used in ATMs

Pointing Devices

• Mouse is a hand-held, small, input device used for pointing, typically having two or three buttons.
• • Left button selects items or click, the right button generates context menus
• • When moved across a flat surface, the graphic cursor moves on the screen with different symbolic texts and changes depending on application. 5 techniques for mouse use:
• • Pointing to move the mouse to an icon
• • Clicking to press/release left button to open icon or menu
• • Double-clicking to press/release button twice to open app
• • Simultaneous clicks to press/release both left/right button
• • Drag to press and hold left button/move mouse
• Mouse variety includes mechanical, optical, serial, and wireless versions.
• A Trackball is a pointing device which is attached to some keyboard
• Trackball contains selection buttons, and to move the graphic cursor, the ball is rolled with fingers or thumbs.
• Track balls come in various shapes and sizes
• Three main shapes are ABALL, A SQUARE, and A SQUARE.
• To operate, move the ball w/ finger until cursor movement is desired
• In some cases, buttons pushed with finger desired direction of cursor movement are implemented
• The advantages of track ball is less desk space, arm movement and strain, as well as increased control with finger.
• Joystick pointing device works on same principle as track ball, with a stick in spherical ball.
• The stick is used to move the cursor at desired position left or right or backward or forward.
• A button is clicked to select items which the cursor points at the moment.
• Joystick is used in video games, flight simulators, and controlling industrial robots, for aircrafts, motorized wheelchairs and submarines
• The advantages of joy stick are that it is easy to lean and inexpensive

Input Devices used for Graphics

• Light pen is used to draw directly on the screen and is used in CAD and is similar to a pen sensing light signal
• • It has a top switch connecting it to the screen and the user needs to bring light pen to a point on and and press make contact on the monitor
• Touch screen is a pointing device which requires simple operation. -- Touch screen allows users to choose available options by just tapping the icon or menu -- Touch screen detects location, requires sensors and communicates with the computer and transfers pressure. -- Touch screen is commonly used in airports, railway stations, stores, museums, and for ATMs, I-phones, PDAs, and computer-based training.
• Touch screen contains touch screen sensor panel, controller, and a software driver.
• • Soft ware drives provides interface which translates touch events in mouse events
• Digitizer input device converts pictures, maps and drawings into digital form.
• • Digitizers is used to hand-draw similar to a pencil and be used to capture data/signatures
• • The user draws on attached stylus connected n connected with the computer in co ordinate of point.

More Input Devices

• Microphone is used to record audio into computer -- Microphones transfer sounds into electrical energy and have a diaphragm to vibrate to cause other components to vibrated -- Microphones are generally split in types, those refer refers to the method the microphones transform the signal and those designed for a specialised use. Web camera is an input device which feeds image to computer or computer network via USB or Wi-Fi using special software.
• Scanner is an input device which scans paper documents in electronic format to be translated into a b stored and provides faster and more accurate data entry.
• There is flatbed and handheld scanners – Flatbed scanners are copier boxes with glass, and has a light to scan -- Scanners are light emitting diodes that is held on the document and if dragged steady the scanner can scan properly.

Optical Scanners

• OMR Reader recognizes a specified type of mark made by a pencil/pen, detects absence of a mark on paper, and detects reflected light from the mark -- OMR uses soft lead pencils, and in reading answer sheets and questionnaires -- OMR Reader has Speedy & accurate output and cheap in cost -- OMR Reader can read characters, erasures or cancellation is not possible ,requires good quality expensive paper.
• OCR Reader is on alphabets & numbers printed on paper. -- It can also recognize shape & identify character directly from document

Other Input Devices

• MICR Reader systems use magnetized ink to print characters, then read and decode with devices. -- The common font is E13B with 0-9 numbers & 4 symbols -- First MICR Reader-Sorter reads the data on cheques and sorts for distribution -- MICR is used in Banks to cheques with a special ink that can be magnetized, E.g. MICR is used in Banks to cheques
• Bar Code Reader codes data using sm line -- Bar Code Reader the alpha numeric data by combination of lines -- Bar Code Reader scans barcode image and converts it into a value. -- Bar Code Reader uses laser-beam technology to which electric pulse is converted to a the alphanumeric value – Most common is the The Universal Product Code (UPC) whose 10 digits shows which product is shown

What is Output Devices

• Output devices display results generated by the computer system, and is a monitor, printer, plotter. speakers.
• Functions of output devices are to accept the result from the CPU, translate it to something human and supply it to the display unit.

Visual Displays VDU

• It can be a high resolution tv set for colors
• There are CRT, and non CRT monitors
• Most Computer monitors are based on Cathode Ray Tube (CRT)
• CRT monitors contains cathode, grid, and is a specialzed vaccum tube
• The CRT monitor Cathode prodcues hig h speed electrons
• Accelerating anodes are applied with positive electrons.

Computer Displays

• CRT Disadvantages & Advantages

  • It produces more colors, price is lower than LCD but consunmes high heavy & needs large space

• LCD (Liquid Crystal Display) between plates

• • Front is tranparent so light can pass through
• • Has an thin film on front plate or coated segments

• -LCD do not give light thesimply change

• -LCD have advantages such as light weight screen and consumed low energy

• -LCD has disadvatanges include fixed resolution

PLASMA Displays Panel

• • In Plasma Displays have gas between glasses and wiring both horizontal and vertical. -- Small gas goes through vertical wire and that create
• • Display employs pixel both high and better resolution than older computers.

What is Printer

• Printers are producing the hard copy output and come in 2 types, called impact and non Impact.
• Characteristics Impact Printer includes contact of device. low cost, noisy, slow and stand with dusty or extreme enviornment
• Non Impact Printer make images on paper directly. There are inkjet and laser printer
• Characteristics includes faster impact printer

Computer Printer Types

• Dot matrix printer is the character printer that uses pins for ink, and moves them to create
• The Dot matrix printer can print 30 to 600 characters per second but has disadvantages include noise and slow speed
• Daisy Wheel printer is the character printer also, though rotating and uses hammer for impact
• • The daisy wheel can print 10 to 50 characters per second because of disadvantages include very slow speed and noisy
• Drum printer is a line printer solid cylindrical drum that is printed at 300 to 2000 lines per minute.
• Chain Printer: Line printer, 400/2500 and chain is easy changed.
• Impact printers all have low costs, can carbon print, can be cleaned but the images can be printed.

Non Impact Printer

INK-JET

• It's a NON and character , 30/400 and they spray with ink for color or monocnhormen
• These printer often silent and can printer graphic with high quality and charaeters
• Laser
• • three laser multi and use electricity, can high speed. It can 4 for 12 per minuente. These printer cannot carbon print but the image of it is high. -- The NON in high quality printer and speed it has advantage both print

Plotter and More

• What a plotter is -- Plotters output output device images, widely used for making and plotting graphics.
• Drum plotter has one the which is placed and rotates
• Flatbed plotter: More and are accurate

Short Notes :

• Graphic speaker -- This connected soundcard to audio sent and it can translate signal and its able make sound

Computer Casings: Parts of Computer

• Dual Core*
• Dual-core: Contains twin processing cores, and this enables the multiple processors from the single silicone processor
• Dual-core chips are high performance power
• Core 2 Duo is often the given to second cores by Intel
• With technology multi you are able work independently

Primary Storage Device

• Storage is temporary in chips
• Instruction on memory when is done very
• Primary memory is only memory to acess by CPU
• Random Access*:
• READ/WRIT*
• The Random Access chips that are fixed to motherboard may have capacities enhanced to use

RAM

• RAM chips =2 Types= DRAM SRAM.

• RAM (Random Access Memory) has complete ability random data from each ROM

• DRAM: (Dynamic Random)

• • It used for access for computer

• SRAM:(Static Random Memory) is volitale and maintained for for memory

• Complete of rom has 1. Data is permanently 2. Micro operate are is is is the ex

CABLES & EXPAIN PORTS

Serial Port

• Data port which use 2 lines and high signal
• Parrallel port, it good input with type of socket and it resevered
• USB Port: new tech connect peripherials in speeds for keyboard
• PI 2*

Following USB Port

• Connecting USB device simple, if you don't know it it gives the disk
• Serial Cable*
• Cables transfers used in RS232.

To use or create what is needed graphics cards in 1. Motherboard

• Graphic cards take the binary and translate to