Computer Hardware, Software and Generations

Hardware

• Hardware is controlled by software to execute commands or instructions.
• A combination of hardware and software creates a functional computing system.
• Computer hardware includes physical components like the case, CPU, RAM, monitor, mouse, keyboard, data storage, graphics card, sound card, speakers, and motherboard.

Software

• Software comprises instructions, data, or programs that operate computers and execute tasks.
• Software is a broad term that includes applications, scripts, and programs that run on a device.
• Software is the variable part of a computer, while hardware is the invariable part.

Generations of Computers

• The evolution of computers started around the 16th century.
• Computers have improved in speed, accuracy, size, and price over time.
• Computer history is divided into generations:
• First Generation (1940-1956)
• Second Generation (1956-1963)
• Third Generation (1964-1971)
• Fourth Generation (1971-Present)
• Fifth Generation (Present and Beyond)

First Generation Computers: Vacuum Tubes (1940-1956)

• Used vacuum tubes, which were fragile glass devices.
• Computers were large, heavy, and unreliable.
• Programming was difficult due to the use of high-level languages and the absence of an OS.
• Used for calculation, storage, and control.
• Required a lot of space and consumed a lot of electricity.

Second Generation Computers: Transistors (1956-1963)

• Used transistors instead of vacuum tubes, making them more efficient.
• Featured core storage.
• Transistors are semiconductor devices that amplify signals or open/close circuits.

Third Generation Computers: Integrated Circuits (1964-1971)

• Used integrated circuits (ICs), also known as silicon chips.
• Integrated circuits involved placing many transistors on silicon chips.
• Improved speed and reliability.

Fourth Generation Computers: Microprocessors (1971-Present)

• Microprocessors were first used in 1971.
• Large Scale Integration (LSI) circuits were built on a single chip, creating microprocessors.
• A single microprocessor contains all the circuits needed for arithmetic, logic, and control functions.

Fifth Generation Computers

• Use Artificial Intelligence (AI) technology.
• Allow computers to behave like humans.
• Used in voice recognition, medicine, entertainment, and game playing.

Hardware Components

• Hardware includes physical devices or tools that can be touched and felt.
• Hardware consists of the monitor, CPU, keyboard, mouse, and other devices connected externally or internally.
• A typical PC includes a desktop or tower case (chassis) with various parts.
• CPU (Central Processing Unit): The processor is the core of the computer, fitted onto the motherboard.
• Motherboard: The system board holding the processor, RAM, and expansion card slots.
• RAM (Random Access Memory): Used for program execution and short-term data storage, contributing to a faster PC.
• Buses: Includes PCI, PCI-E, ISA (outdated), USB, and AGP, which facilitate communication between components.
• Power Supply: A case containing a transformer, voltage control, and a fan to provide power.
• Storage Controllers: IDE, SCSI, or other types that control hard disks, floppy disks, CD-ROMs, and other drives, usually located on the motherboard or expansion cards.
• Video Display Controller: Produces the output for the computer display.
• Computer Bus Controllers: Parallel, serial, USB, and FireWire connect the computer to external devices like printers and scanners.
• Removable Media Writer: A device for writing data to removable media such as CDs.
• CD: A common, inexpensive but fragile type of removable media.
• Other Storage Devices:
• CD-ROM, CD-RW, CD-R, DVD, DVD-ROM, DVD-RW, DVD-R: Various types of optical discs.
• Floppy Disk: An older storage medium.
• Tape Drive: Used for backup and long-term storage.
• Internal Storage: Keeps data inside the computer for later use.
• Hard Disk: For medium-term data storage.
• Sound Card: Translates signals from the system board into analog voltage levels for speakers.
• Networking: Connects the computer to the Internet or other computers.
• Modem: Used for dial-up connections.
• Network Card: Used for DSL/Cable internet connections.
• Other Peripherals: -Standard or common external components.
• Input: Keyboard, pointing devices like mice, trackballs, joysticks, and game pads.

Input Devices

• Accept data and instructions from the outside world.
• Convert data into a form the computer can understand.
• Keyboards:
• Popular input device with a layout similar to a typewriter.
• Available in different sizes: 84 keys, 101/102 keys, or 104/108 keys.
• Mouse:
• Popular pointing device for cursor control.
• Has a palm-sized box with a ball that senses movement.
• Sends signals to the CPU when buttons are pressed.
• Typically has left and right buttons and a wheel.
• Controls cursor position but cannot enter text.
• Joystick:
• A pointing device used to move the cursor on a monitor.
• Consists of a stick with a spherical ball at both ends.
• Moves in all four directions within a socket.
• Used in Computer Aided Designing (CAD) and computer games.
• Light Pen:
• A pointing device similar to a pen, used to select menu items or draw on the screen.
• Contains a photocell and optical system in a small tube.
• Detects screen location and sends signals to the CPU when the tip is moved and the button is pressed.
• Track Ball:
• An input device used in laptops, instead of a mouse.
• Has a ball that is half-inserted; moving fingers on the ball moves the pointer.
• Requires less space than a mouse.
• Comes in various shapes like a ball, button, or square.
• Scanner:
• An input device that functions like a photocopy machine.
• Transfers information available on paper to the hard disk. Captures images and converts them into a digital form that can be stored on the disk. Images can be edited before printing.
• Digitizer:
• Converts analog information into digital form.
• Can convert signals from a TV or camera into a series of numbers.
• Used to create a picture of whatever the camera is pointed at.
• Also known as a Tablet or Graphics Tablet, which converts graphics and pictorial data into binary inputs.
• Used for fine works of drawing and image manipulation.
• Microphone:
• Is an input device to input sound that is then stored in a digital form.
• Used for adding sound to presentations or mixing music.
• Magnetic Ink Card Reader (MICR):
• Used in banks to process a large number of checks.
• Reads bank code and cheque number printed on checks with magnetic ink.
• Uses Magnetic Ink Character Recognition (MICR) for fast and less error-prone reading.
• Optical Character Reader (OCR):
• Is an input device used to read a printed text.
• Scans text optically, converts it into a machine-readable code, and stores it in the system memory.
• Bar Code Reader:
• Reads bar coded data (light and dark lines) used in labeling goods and numbering books.
• May be a handheld or stationary scanner.
• Scans a bar code image, converts it into an alphanumeric value, and sends it to the connected computer.
• Optical Mark Reader (OMR):
• Recognizes the type of mark made by pen or pencil.
• Used for checking multiple-choice exam answer sheets.

Output Devices

• Monitors (Visual Display Units - VDUs):
• The main output device of a computer.
• Forms images from tiny dots called pixels arranged in a rectangular form.
• Image sharpness depends on the number of pixels.
• Two types of viewing screens: Cathode-Ray Tube and Flat-Panel Display.
• Cathode-Ray Tube (CRT) Monitor:
• Composed of small picture elements called pixels.
• Smaller pixels result in better image clarity or resolution.
• Employs multiple illuminated pixels to form characters.
• Can display a finite number of characters (80 horizontally and 25 vertically).
• Disadvantages: Large size and high power consumption.
• Flat-Panel Display Monitor:
• Video devices with reduced volume, weight, and power requirement, compared to CRT.
• Can be hung on walls or worn.
• Used in calculators, video games, laptops, and graphics displays.
• Flat-panel displays divided into:
  • Emissive Displays: Convert electrical energy into light (e.g., plasma panels and LEDs).
  • Non-Emissive Displays: Use optical effects to convert light (e.g., LCDs).
• Printers:
• An output device used to print information on paper.
• Two types: Impact Printers and Non-Impact Printers.
• Impact Printers: -Print characters by striking them on the ribbon, which is then pressed on the paper.
• Non-Impact Printers:
• Print characters without using a ribbon.
• Print a complete page at a time, also called Page Printers.
• These include: Laser Printers and Inkjet Printers.
• Advantages: Less noise and various printing styles available. Color printing is possible, and some inkjet models can produce multiple copies.

Computer Processing and Memory

• Computers process data, pictures, sound, and graphics, solving complex problems quickly and accurately.
• Input Unit:
• Computers need to receive data and instructions to solve problems.
• Consists of one or more input devices, such as a keyboard, mouse, floppy disk drive, or magnetic tape.
• Accept data and instructions from the outside world and convert the data into a form that the computer understands.
• Memory Hierarchy:
• Digital computers use the binary system (0s and 1s).
• Each character or number is represented by an 8-bit code (a byte). A character occupies 1 byte space. A numeric occupies 2 byte space.
• Byte is the space occupied in memory.
• Primary storage size is specified in KB (Kilobytes) or MB (Megabytes).
• 1 KB = 1024 bytes, and 1 MB = 1000 KB.
• Memory Sizes: Typically start at 16MB. PCs often have 32 MB, 48 MB, 128 MB, or 256 MB.
• Storage Unit:
• Holds data and instructions entered through the input unit. Preserves intermediate and final results before sending them to output devices. Saves data for later use.
• Storage devices are divided into:
  • Primary memory: Stores and provides very fast data.
    • Used to hold programs being currently executed, data from the input unit, and intermediate and final results.
    • Temporary in nature; data is lost when the computer is switched off. -More expensive.
  • Secondary memory: Used as an archive for storing programs, documents, and databases.
    • Programs are transferred to primary memory before execution.
    • Slower but cheaper than primary memory.
    • Common devices include hard disks and CDs.

System Software

• Designed to run a computer's application programs and hardware.
• Coordinates the activities and functions of hardware and software.
• Controls computer operations and provides a platform for other software to work.
• Examples of system software include the OS, firmware, computer language translators, and system utilities.

Application Software

• Computer software packages that perform specific functions for users or other applications.
• Can be self-contained or a group of programs.
• Examples include office suites, graphics software, databases, web browsers, word processors, software development tools, image editors, and communication platforms.

Packages

• Collections of programs that perform similar functions or have similar features.
• Microsoft Office includes multiple applications like Excel, Word, and PowerPoint.
• Video and audio editing software are also available as packages.
• Purchasing packaged software can be more cost effective than buying individual programs separately.

Frameworks

• Software frameworks are abstractions providing generic functionality that can be changed by user-written code for application-specific software.
• Provide a standard way to build and deploy applications.
• Universal, reusable software environments that provide particular functionality.
• Includes support programs, compilers, code libraries, toolsets, and APIs to enable project or system development.

IDES

• Integrated development environments (IDEs) are software applications that help programmers develop software code efficiently.
• Increase developer productivity by combining software editing, building, testing, and packaging in an easy-to-use application.