Chapter 1: Types & Components of Computer Systems

1. Hardware vs. Software

  • Hardware = tangible, physical components of a computer system.

    • Exist as electronic / mechanical parts you can touch.

    • Sub-divided into internal components (built into the case) and external components / peripherals (plugged in or connected).

  • Software = sequences of instructions (code) that tell the hardware what to do.

    • Intangible (though stored on physical media).

    • Two main classes: Application software (task-oriented) and System software (computer-oriented).

2. Internal Hardware Components

  • Central Processing Unit (CPU)

    • Called the “brain” of the machine. Executes program instructions & coordinates the whole system.

    • Contains an Arithmetic Logic Unit (ALU) that performs Boolean logic and arithmetic such as ANDAND, OROR, NOTNOT, ++, −-, etc.

    • Speed / performance measured in GHz\text{GHz} (clock rate), core count, and cache sizes.

  • Motherboard / Mainboard

    • Printed circuit board distributing power & data signals between CPU, memory, and all other devices.

    • Hosts firmware (BIOS / UEFI), expansion slots, chipsets, buses.

  • Main Memory

    • Holds data / instructions currently in use so CPU can access them rapidly.

    • Implemented with RAM (volatile) and ROM / Flash (non-volatile firmware).

  • Graphics (Video) Card

    • Dedicated processor (GPU) that converts binary data into video signals for monitor.

    • Necessary for 3-D graphics, gaming, CAD, GPU computing.

  • Sound Card

    • Converts digital audio to analog output and vice-versa; provides audio jacks, MIDI, surround-sound support.

  • Internal Hard-Disk Drive (HDD) / Solid-State Drive (SSD)

    • Mass storage; capacities span GB – TB\text{GB – TB}.

    • SSD has no moving parts → faster, silent, shock-resistant.

  • Network Interface Card (NIC)

    • Wired (Ethernet) or wireless (Wi-Fi, Bluetooth); MAC address uniquely identifies each interface.

  • Optical Drive (CD / DVD / Blu-ray)

    • Reads (and sometimes writes) optical discs using lasers.

  • Power Supply Unit (PSU)

    • Converts 230 V230\,\text{V}/110 V110\,\text{V} AC main electricity to low-voltage regulated DC rails (e.g., +12 V+12\,\text{V}, +5 V+5\,\text{V}, +3.3 V+3.3\,\text{V}).

3. External Hardware Devices & Peripherals

  • Input Devices (send data INTO the computer)

    • Mouse, keyboard, microphone, scanner, digital camera, webcam, gamepad, joystick, touchpad, trackerball, bar-code reader, MIDI keyboard, touch-screen (both in/out), burglar alarm sensors, modem (both).

  • Output Devices (receive data FROM computer)

    • Monitor, projector, speakers, printer, plotter, touch-screen (feedback vibration/visual), modem.

  • External Storage

    • External HDD / SSD, USB flash drive, SD card, cloud-attached storage.

  • Devices that act as both Input & Output (circled in tasks):

    • Touch-screen, Modem, (also Fax, VR controllers, etc.).

4. Memory Technologies

  • ROM – Read-Only Memory

    • Stores firmware (bootstrap, BIOS/UEFI).

    • Non-volatile → retains contents when power is off.

    • Usually flash-programmable nowadays (EEPROM).

  • RAM – Random-Access Memory

    • Temporary workspace for OS, apps, data.

    • Volatile → contents lost at power-down.

  • Key Difference

    • ROM is non-volatile; RAM is volatile.\text{ROM is non-volatile; RAM is volatile.}

  • Volatile vs. Non-volatile

    • Volatile: needs continuous power (e.g., DRAM, SRAM).

    • Non-volatile: retains data without power (e.g., ROM, Flash, SSD, HDD, optical, magnetic tape).

5. Classification of Storage

  • Primary storage = memory directly accessible by CPU (registers, cache, RAM).

  • Secondary / Backing storage = non-volatile, larger; e.g., HDD, SSD, optical discs.

6. Application Software (Detailed)

  • Word Processing

    • Tools: formatting, font styling, page layout, spell-check, import images/tables, copy/paste\text{copy} / \text{paste}, find/replace\text{find} / \text{replace}.

  • Spreadsheet

    • Formulas: SUM\text{SUM}, MAX\text{MAX}, MIN\text{MIN}, AVERAGE\text{AVERAGE}, COUNT\text{COUNT}, COUNTA\text{COUNTA}, COUNTIF\text{COUNTIF}, SUMIF\text{SUMIF}, IF\text{IF}, nested IF\text{IF}, VLOOKUP / HLOOKUP\text{VLOOKUP / HLOOKUP}.

    • Data visualisation: bar / pie charts, conditional formatting.

  • Database Management Systems (DBMS)

    • Tables with fields & records, search queries, reports, labels; SQL under the hood.

  • Photo Editing

    • Adjust brightness/contrast, filters, layers, lighting, liquify, clone/stamp.

  • Graphics Manipulation

    • Bitmap pixel editing & vector objects (lines, curves, text).

  • Video Editing

    • Split/trim clips, reorder timeline, transitions (fade), insert audio, apply filters.

  • Phone Apps / Applets

    • Categories: games, social media, communication, streaming, GPS, health. Installed via app stores; updated frequently.

  • Measuring Software

    • Reads sensor data (temperature, pressure) for logging.

  • Control Software

    • Compares sensor values with preset targets; issues actuator commands (e.g., greenhouse heater on/off).

7. System Software

  • Operating Systems (OS)

    • Manage hardware, memory, files; provide CLI (command-line) or GUI (graphical) interface.

    • Multitasking, security, device management.

  • Device Drivers

    • Low-level code enabling OS to communicate with specific hardware models.

  • Utilities

    • Maintenance: antivirus, disk defrag, backup, compression, diagnostics.

  • Compiler

    • Translates high-level source code into machine code/executable.

  • Linker

    • Combines multiple object files and libraries into one program.

8. User Interfaces Beyond GUI & CLI

  • Menu-based Interface

    • Hierarchical list of options (e.g., ticket machine, ATM). Simple, good for novices.

  • Form-based Interface

    • Text boxes, drop-downs for data entry (e.g., hotel booking sites). Ensures structured input.

  • Natural-Language Interface

    • Accepts spoken or typed everyday language (smart speakers, chatbots). Requires NLP & AI.

  • Dedicated Appliance Interfaces

    • Washing machine: dials / buttons + LEDs; optimised for quick, robust control → not GUI due to cost & moisture.

    • Digital camera: mode dial, shutter button, small LCD + buttons / touch. Designed for portability & battery life.

9. Personal / Desktop vs. Laptop Computers

  • Desktops:

    • Large, upgradable, better cooling, usually tethered to mains. Ideal for power users & servers.

  • Laptops:

    • Portable, built-in battery, integrated display, lower weight, Wi-Fi. Some performance trade-off; can run standalone or on a network.

10. Tablets & Smartphones

  • Touch-centric, sensors (gyro, GPS), always-on connectivity (Wi-Fi, 3G/4G/5G3\text{G} / 4\text{G} / 5\text{G}, Bluetooth).

  • Use ARM processors for low power.

11. Microprocessors in Everyday Devices

  • Found in: washing machines, microwave ovens, heating thermostats, smart TVs, cars, burglar alarms, drones.

  • Advantages: automation, precision, energy savings, self-diagnostics, accessibility (e.g., for disabilities).

  • Disadvantages: complexity, cost, electronic waste, security/privacy vulnerabilities, dependency on electricity.

12. Emerging Technologies & Human Impact

  • Self-driving cars:

    • Pros: mobility for impaired users, reduced accidents (theoretically), optimized traffic.

    • Cons: ethical liability, hacking risk, job displacement (drivers), public trust.

  • IoT & Smart Homes: convenience vs. privacy.

  • Wearables & Health Tech: real-time monitoring, but data security concerns.

13. Quick Revision Questions (from transcript) – Suggested Talking Points

  • List external devices & classify input/output; note dual-function items.

  • Browser = generic name for internet software.

  • Custom vs. Off-the-shelf software: tailored fit, competitive edge, but higher cost/time.

  • ROM: stores firmware, non-volatile. RAM: working memory, volatile.

  • Investigate other UIs (voice, gesture, VR).

  • Discuss microprocessors in household devices: advantages (automation) & disadvantages (over-reliance).

14. Key Terms Summary

  • ALU – part of CPU performing arithmetic/logic.

  • Firmware – software permanently stored in ROM.

  • Volatile Memory – needs power to retain data.

  • Non-volatile Memory – retains data without power.

  • Peripheral – external device providing input/output/storage.

  • Utility Program – system software performing maintenance.

  • Driver – system code enabling OS ↔ hardware communication.