Computer Components: Hardware, Software, and CPUs

Components of the Computer

• Hardware is the tangible, visible parts of a computer consisting of electromechanical components.
• Software is a set of programs that help to use computer systems and electronic devices effectively.
• Humanware (or Liveware) refers to humans who use computers.

Hardware Components

• The processor (CPU), motherboard, peripherals and ports, memory (primary and secondary), and input/output devices are hardware components.

Processor (CPU)

• The CPU is responsible for computing, decision making, and coordinating computer operations.
• It is an Integrated Circuit (IC) package with millions of transistors fabricated into a single silicon chip (microprocessor).
• CPUs are plugged into a large socket on the motherboard.
• Common examples include Intel Core i3, i5, i7, and AMD Quadcore processors.
• Registers inside the CPU are storage locations that can be accessed more quickly than other memory.
• Accumulator: A part of the Arithmetic Logic Unit (ALU) used to store data for arithmetic and logical operations.
• Memory Address Register (MAR): Stores the memory location address where data will be read from or written to by the processor.
• Memory Buffer Register (MBR): Holds data to be written to or read from memory by the processor.
• Instruction Register (IR): Stores the instructions to be executed by the processor.
• Program Counter (PC): Holds the address of the next instruction to be executed by the processor.

Motherboard

• The motherboard is a large Printed Circuit Board (PCB) that integrates all major components, including the processor.
• It provides expansion slots for additional circuit boards like memory, graphics, and sound cards.

Peripherals and Ports

• Peripherals are devices attached to a computer.
• Ports on the motherboard connect external devices.
• Peripherals include input, output, external storage, and communication devices.
• Peripheral devices communicate with the motherboard through ports like VGA, PS/2, USB, Ethernet, and HDMI.
• Serial ports transmit one bit of data at a time, used in older computers for devices like modems, mice, and keyboards, and are now replaced by faster ports such as USB.
• Parallel ports transmit several bits of data simultaneously, are faster than serial ports and are used to connect printers or scanners.
• USB (Universal Serial Bus) provides high-speed data communication and short-distance connections for devices like keyboards, mice, printers, flash drives, and external hard disks.
• USB ports can supply electric power to external devices.
• USB devices can be connected/disconnected while the power is on.
• LAN ports (Ethernet) connect a computer to a network using a wired connection, using registered jack RJ45 connector.
• PS/2 ports (Personal System/2) are special ports used by IBM for connecting keyboards and mice but are now replaced by faster ports like USB.
• Audio ports connect audio devices like speakers and microphones.
• VGA port (Video Graphics Array) connect a monitor or projector to a computer and is a popular display standard from IBM.
• HDMI (High Definition Multimedia Interface) transmits high-definition video and multi-channel audio over a single digital connection cable.

Memory

• Memory stores data, instructions, and results temporarily or permanently.
• Primary memory holds data and results of ongoing jobs temporarily.
• Secondary memory holds data and information permanently.
• Memory measurements:
• Binary Digit = 1 Bit
• 1 Nibble = 4 Bits
• 1 Byte = 8 Bits
• 1 KB (Kilo Byte) = 1024 Bytes
• 1MB (Mega Byte) = 1024 KB
• 1 GB (Giga Byte) = 1024 MB
• 1 TB (Tera Byte) = 1024 GB
• 1 PB (Peta Byte) = 1024 TB

Primary Memory

• Primary memory is semiconductor memory accessed directly by the CPU and includes RAM, ROM, and cache memory.
• RAM (Random Access Memory):
• Faster than ROM.
• Stores the OS, application programs, and data while the computer is running.
• Allows reading and writing.
• Volatile, losing contents when power is off.
• ROM (Read-Only Memory):
• Slower memory.
• Stores the program to boot the computer.
• Usually allows reading only.
• Non-volatile, retaining contents when the device is powered off.
• Types of ROM:
• PROM (Programmable ROM): Programmed only once at manufacture.
• EPROM (Erasable Programmable ROM): Can be erased with ultraviolet radiation and reprogrammed using special electronic circuits.
• EEPROM (Electrically Erasable Programmable ROM): Can be erased and rewritten electrically.
• Cache Memory:
• Small, fast memory between the processor and RAM that stores frequently accessed data and instructions for quick access.
• More expensive than RAM.
• Level 1 Cache: 128 KB, Level 2 Cache: 1 MB, Level 3 Cache: 8 MB, and Level 4 Cache: 128 MB.

Secondary Memory

• Secondary/Auxiliary memory: It is permanent, stores data even when power is off, and is used for data transfer and backup and uses magnetic, optical, and semiconductor technologies.
• Magnetic Storage Devices:
• Use plastic tape or metal/plastic disks coated with magnetic materials, using read/write heads to access data, and include magnetic tapes, floppy disks, and hard disks.
• Magnetic tape: Can store huge volumes of data with low cost per unit volume.
• Hard Disk:
• Consists of metal disks coated with magnetic material in dust-free containers, offering high storage capacity, high data transfer rates, and low access time.
• Can contain one or more platters, each with two read/write heads.
• Data is stored on the platter's surface in sectors and tracks, tracks are concentric circles and sectors are pie-shaped slices.
• Optical Storage Devices:
• Use low-powered laser beams to read and write data.
• Consist of an aluminum foil sandwiched between two circular plastic disks..
• Compact Disk (CD): Optical storage medium storing up to 700 MB of data and uses red laser beams for reading/writing data, available as CD-R and CD-RW.
• Digital Versatile Disk (DVD): Optical storage offers higher capacity, recording/reading data using a DVD drive and red laser; capacity ranges from 4.37 GB to 15.9 GB.
• Three DVD types: DVD-ROM (read only), DVD-RW (rewritable), and DVD-RAM (random access memory).
• A normal DVD (DVD-5) stores 4.37 GB, while a dual-layer double side DVD (DVD-18) stores 15.9 GB.
• Semiconductor storage (Flash memory): Are faster and more durable.
• USB flash drives: Portable, rewritable, with storage from 2 GB to 32 GB.
• Flash memory cards: Flat, small (1 inch x 0.75 inch x 2 mm), with storage from 1 GB to 32 GB; smaller versions used in cell phones and tablets.

Inputs

• Devices used to feed data into a computer, providing communication between the user and the computer.
• Common devices:
• Keyboard: Standard input device; US keyboard has 101 keys (QWERTY), available as wired and wireless.
• Mouse: Small hand-held device using ball, optical, or laser technology; wired uses serial, PS/2, or USB ports, while wireless uses radio waves.
• Light pen: Pointing device shaped like a pen used by engineers, artists, etc., for Computer Aided Designing (CAD).
• Touch screen: It allows users to operate the display screen by touching, and can be operated with a stylus.
• Graphic tablet: Consists of an electronic area and special pen, allowing artists to create graphical images.
• Touchpad: Found on portable computers, allows users to move the mouse pointer without an external mouse.
• Joystick: Input device for video games, simulators, and robots; has a vertical stick and a button for selecting options.
• Microphone: Inputs analogue sound and converts it into digital format for processing and playback.
• Scanner: Captures information, and converts it into a digital format using resolution measured in Dots Per Inch (DPI).
• Optical Character Recognition (OCR): Software recognizes printed text, converts it into editable text format.
• Optical Mark Reader (OMR): Scans printed forms, reads predefined positions, records marks, and is used for objective tests and questionnaires.
• Barcode Reader: Hand-held scanners scan codes for billing and price information.
• QR code Reader: Scans QR codes (2D barcodes) for website URLs, text, contact info, and requires a special barcode reader or smartphone with camera and software.
• Magnetic Ink Character Recognition (MICR) Reader: Used in banks for faster cheque processing, speeding up money transfer.
• Biometric sensor: Identifies unique human physical features (fingerprints, retina) and verifies/authenticates identity.
• Smart card reader: Reads plastic smart cards with memory/microprocessors to store data for banking, healthcare, and electronic payments.
• Digital camera: Takes digital pictures/videos, with quality determined by lens, CCD density, resolution, zoom, and software.
• Web camera: Compact, inexpensive digital camera for video calling/chatting (no internal memory).

Outputs

• Output Devices include visual display units, printers, and plotters.
• Produces either hardcopy which are permanent in nature or softcopy outputs which are electronic and available on screen.
• Visual Display Unit (VDU): Visually conveys text, graphics, and video.
  • Types: Cathode Ray Tube (CRT), Liquid Crystal Display (LCD), Thin Film Transistor (TFT), Light Emitting Diode (LED), and gas plasma monitors.
  • CRT: Similar to televisions; monochrome displays a single color on dark, color monitors uses different colors.
• Flat panel monitor: Is thinner, and lighter, consumes less power which commonly used in computers and laptops (LCD, LED, Plasma, and OLED).
• LCD Monitors: Use liquid crystals between plastic plates; crystals rearrange to form an image when electric current is passed through for visibility using a fluorescent lamp or LED backside lighting.
• LED Monitors: Enhance LCDs using LEDs directly behind the screen for better contrast, clarity, viewing angle, quicker refresh rates and have power savings.
• Plasma Monitors: Consists of Neon/Xenon gas between two glass plates, high resolution but expensive, and provides a flat-panel display.
• Organic Light Emitting Diode (OLED): Millions of tiny LEDs made of organic material, screens are thinner and lighter than LCD and LEDs.
• LCD projector: Projects video, and images to large surfaces by emitting light.
• Printers: Are used to produce a hardcopy output.
• Dot Matrix Printer (DMP):Uses electromagnetically activated pins, and 9 or 24 pins for printing slowly.
• Inkjet Printers : Image is formed, and multicoloured by the means of colours cyan, magenta and have black ink cartridges costing.
• Laser printers : The toner is heated, and produces graphics by means of monochrome.
• Thermal printer :It makes use of specialised heat sensitive paper, prints quietly, and quickly and often used in POS terminals.
• Plotter: Output device produces a large copy, two types are as follows Drum, and Flatbed which is known more recently as the table plotter.
• Three Three dimensional printer makes use to modern tech and helps to create products and designs from house mugs to machine parts.
• Audio output device:
• Computer’s ability to produce sound using speakers through various ports.

Electronic Waste

• E-waste includes used electronics destined for reuse, resale, salvage, recycling, or disposal and contains toxic substances like mercury, lead, cadmium, and brominated flame retardants that lead to health issues.
• Hazardous chemicals in e-waste:
• Lead: Found in solder on circuit boards and in computer monitor glass, causing damage to the nervous, blood, and kidney systems.
• Mercury: Found in printed circuit boards and LCD screen backlights, affecting a baby's growing brain and adults' nervous system, organ damage, and mental impairment.
• Cadmium: Found in chip resistors and semiconductors, causing cancer and accumulating in the kidneys.
• BFRs-Brominated Flame Retardants: Found in printed circuit boards and some plastics, increasing the risk of cancer.
• E-waste disposal methods:
• Reuse: Reusing equipment after upgrades and modifications.
• Incineration: Burning e-waste at high temperatures (900 to 1000 degrees Celsius).
• Recycling: Making new products from e-waste.
• Landfilling: Least favored as it buries waster material into the ground.
• Student's role in e-waste disposal:
• Stop buying unnecessary electronics.
• Repair faulty equipment.
• Recycle electronics.
• Buy durable, safe products.
• Check for exchange schemes.
• Buy rechargeable battery products.

Green Computing (Green IT)

• Green computing is the study and practice of eco-friendly computing, including design, manufacturing, use, and disposal of computers and components.
• How to reduce the impact on the global environment:
• Turn off devices when not in use.
• Use power saver mode.
• Use laptops instead of desktops.
• Avoid unnecessary printouts.
• Use LCDs instead of CRTs.
• Use Energy Star-rated products.
• Dispose of e-waste properly.
• How to make computers more environmentally friendly:
• Green design: Creating energy-efficient and eco-friendly devices.
• Green manufacturing: Reducing waste during manufacturing processes.
• Green use: Minimizing electricity consumption.
• Green disposal: Reconstructing and recycling electronics.

Software Categories

• System software: Operates the hardware, manages the software plus it is classified further as three categories. The first is operating system.
• Major functions of an operating system:
• Process Management It takes care of the allocation and de-allocation of processes and scheduling of various system processes.
• Memory Management Handles or manages primary memory. It keeps track of each and every memory location, allocates and de-allocates memory.
• File Management It takes care of file related activities such as organising, naming, storing, retrieving, sharing, protection and recovery.
• Device Management It handles the devices connected to the computer by combining both hardware andsoftware techniques. The OS communicates with the hardware device via the device driver software.
• Programing languages : Languages understood by computers. Types of programing languages:
  • Machine language : Low level programming, binary digits
  • Assembly language :Symbolic Name operations/ Mmemnonies
  • HLL or High Level Languages : Not understood by Compilers/ Basic.
• Language Processors: Convert High Level language to machine.
  • Assembler: Translates code that uses the assembly style to a machine code
  • Interpreter : Interprets and converts HL code line by line making it easier to translate after corrections.
  • Compiler : Converts full on files of HL. code to machine, files without errors allows translation fully.
• Utility Software: Is a set of programs which help users in system maintenance tasks and in performing tasks of routine nature such as Large files compressed and or made smaller. Compression, Winzip is popular and is of the zip type, or decompression to extract. Defragmenter which makes work flow with computers quickly
• It helps duplicating information.
• Anti virus software. Helps secure computer.
• Application Software, specific, and more defined work use, and these includes word processor
• Word processing software : helps alter formats for documents / Open Writer
• Spreadsheet software : Excel.
• Presentation software : Power point
• Data base software: Organised sets of info.
• Multi media software : Integration. It includes media such as music, video etc/ VLC media player.
• Applications has specific use and maintains detail in business firm for salary or records.
• Specialised functions/ tailors
• Free open source software includes:
• This allows freedom to use and improve and has four freedoms with software.
• Freedom O with using the software is for any use.
• Freedom 1 how it can be used and adapted.
• Freedom for copying 2 of this software.
• And Freedom 3 allows improvements.
• GNU,Linux and Open office
• Software which is able for trial is a Shareware.
• Software with no limited capacity is a Freeware.