Chapter 1 Notes: Types and components of computer systems

Learning objectives

Define the physical components of hardware for a computer system, including identifying internal hardware devices
Identify external hardware devices and peripherals
Define software as programs for controlling the operation of a computer or processing of electronic data
Define applications software
Define and describe system software and describe operating systems which contain a command line interface (CLI) and a graphical user interface (GUI)
Describe the central processing unit (CPU) and its role
Describe internal memory, i.e. ROM and RAM and the differences between them
Define input and output devices and describe the difference between them, as well as secondary/backing storage
Describe and compare the characteristics and uses of a personal/desktop computer and a laptop computer, as standalone and networked computers
Describe the characteristics and uses of tablet computers and smartphones, including their ability to use wireless technology or 3G/4G technology
Describe how emerging technologies are having an impact on everyday life

Overview: ICT chapter focus

ICT systems combine hardware and software to perform tasks and impact society
Distinguish between hardware (tangible components) and software (instructions that run on hardware)
Learn hardware components, OS varieties, and emerging technologies
Consider real-world implications of technology on daily life

Hardware vs. Software

Hardware: the physical parts of a computer system you can touch (e.g., case, screen, keyboard, mouse, monitor, printer, USB drive; inside the case: motherboard, CPU, RAM, hard drive, optical drive, sound card, video card, cooling)
Software: a set of instructions that enables the hardware to perform tasks; cannot be touched
Two main software types:
- System software: essential to operate the computer; includes OS, device drivers, utility software, BIOS, etc.
- Applications software: programs that perform user tasks (word processing, spreadsheets, etc.) and require the OS to run
An OS provides a platform for applications to run and interfaces with users via GUI or CLI

Key hardware terms and components

Motherboard: main printed circuit board that allocates power to CPU, RAM, and other components; enables communication between them
CPU (central processing unit): executes programs and performs calculations
- Contains ALU (arithmetic logic unit): performs calculations and logical operations (AND, OR, NOT), bit-shifting (left/right shifts), and arithmetic (add/subtract; enabling multiply/divide via these operations)
- Contains CU (control unit): reads and interprets memory instructions and activates components
- Cache: high-speed memory for frequently used instructions/data
Power supply: converts AC to DC power and supplies components
RAM (Random Access Memory): volatile main memory; stores data and programs currently in use; loses contents when power is off
ROM (Read-Only Memory): non-volatile startup memory containing start-up instructions; cannot be changed during normal operation
Storage: backing/secondary storage (non-volatile) for long-term data; examples include hard disk drives (HDDs), USB flash drives, optical disks
Internal vs external hardware:
- Internal: components inside the case (CPU, RAM, motherboard, HDD/SSD, GPU, sound card, cooling)
- External: peripherals like keyboard, mouse, printer, scanner, etc.
Input devices: put data into the computer (peripherals); examples include keyboard, mouse, trackpad, microphone, barcode scanner, scanner, digital camera, joystick
Output devices: show results from the processor (peripherals); examples include printers, speakers, projectors, display screens
Video card (graphics card) and sound card: internal expansion cards for video and audio output
Optical drive: reads/writes CDs/DVDs
Peripheral devices can be internal or external; many are hot-pluggable (e.g., USB devices)
The CPU is mounted in a socket on the motherboard; multiple devices connect via buses and cables

The binary number system and data representation

Computers store and process data using the binary number system (0s and 1s)
A bit (binary digit) is the smallest unit of data (0 or 1)
Eight bits form a byte: $ext{byte} = 8 ext{ bits}$
Data is represented by patterns of bits; e.g., the letter 'A' may be represented as $01000001$ , and 'B' as $01000010$
Reason: electrical signals can be on/off; computers only understand these on/off states
Internal hardware uses components like ALU, registers, and buses to process and move binary data
Video card, sound card, and HDD translate and manage data to/from the display, speakers, and storage

ROM, RAM and memory concepts

Read-Only Memory (ROM): startup instructions; non-volatile; contents persist when power is off; cannot be changed in normal operation
Random Access Memory (RAM): volatile memory; stores data and programs currently in use; loses contents when power is off
Main memory is called RAM/ROM (also IAS/primary/internal memory)
Startup sequence: ROM holds essential startup code; the system loads OS and programs into RAM when powered on
Volatile vs non-volatile memory:
- RAM is volatile: $ext{RAM is volatile} ightarrow ext{contents lost on power off}$
- ROM is non-volatile: $ext{ROM is non-volatile} ightarrow ext{contents preserved on power off}$
Backing storage (secondary/external storage): stores programs and data when the processor is powered off; examples: HDDs, USB drives, SSDs
Do not confuse ROM with optical media (CD/DVD ROM) which are read-only access to data on discs; different types of ROM stored on chips/on-board

External hardware devices and peripherals (examples)

Common external devices: keyboard, mouse, trackpad, printer, scanner
Input devices also include microphone, barcode readers, digital cameras, joysticks, gamepads, webcams, MIDI keyboards
Output devices include printers, speakers, plotters, projectors
Some devices can be both input and output (e.g., touch screens, some multifunction devices)

Input vs Output, and the role of the OS

Input devices: used to put data into the computer; often referred to as peripherals
Output devices: used to show results from processing
Operating systems (OS) provide an interface between the user and hardware
OS types and interfaces:
- GUI (Graphical User Interface): uses icons, windows, menus; user interacts via mouse/pointer; common example: Windows
- CLI (Command Line Interface): type commands at a prompt; more precise but requires knowledge of commands; used by technicians and advanced users
- CLI commands example: COPY, RENAME; processed by the command processor/command-line interpreter
GUI vs CLI trade-offs: GUI is easy for general users; CLI offers powerful control for advanced tasks
The OS also includes: loaders for programs, device drivers for peripherals, linkers to combine code, and utilities to configure, optimize, and maintain the system
BIOS (Basic Input/Output System): translates OS commands into hardware actions; essential for startup
Hypervisor: enables multiple operating systems to run on the same hardware by virtualizing resources
Bootloader: small code that runs at startup to boot the OS
Shell: interface to access OS services

Operating systems and interfaces

Common OS examples: Microsoft Windows (PCs), OS X (Mac), Linux (open-source)
Windows and OS X generally come preloaded on consumer devices; Linux is open-source and modifiable
GUIs are often referred to as WIMPs (Windows, Icons, Menus, Pointers)
A GUI enables interaction through icons and windows; a CLI requires typing commands precisely

Types of computers and portability (1.04)

Desktop computers: fixed location; separate case, monitor, keyboard, mouse; can be all-in-one where components are in the monitor case
Laptop computers: integrated components (computer, monitor, keyboard, touchpad) in a single portable unit; portable with built-in battery
Tablets: handheld, internet-enabled, touch screen; run apps; often connect via WiFi; 3G/4G variants provide cellular connectivity
Smartphones: multifunction mobile devices with cameras, browsers, GPS, sensors; run apps; small screen; highly portable
All four types can be networked; sharing resources like printers and files is common in home networks
Cellular connectivity (3G/4G) adds internet access away from WiFi; cost implications include device price and service plans

Portable computing: table of types and pros/cons (Table 1.01)

Tablets
- Advantages: quick startup, portable, easy to use, lots of apps, data transfer capability
- Disadvantages: may be expensive, limited expandable memory, some lack cellular connectivity or have costly contracts
- Main uses: portable entertainment, web browsing, reading, email, video calls
Smartphones
- Advantages: pocket-sized, make calls/texts/emails, wide app ecosystem, 3G/4G connectivity
- Disadvantages: small screens for reading, battery drain with heavy use
- Main uses: web access, email, data transfer, multimedia, navigation, GPS, apps
Laptops
- Advantages: excellent for work, full-size keyboard, large storage, easy to upgrade (to some extent)
- Disadvantages: heavier than tablets/smartphones, slower to start than tablets
- Main uses: work and home applications, media consumption
Not all devices share exact specs; variability exists across models

Impact of emerging technologies

Artificial Intelligence (AI): systems that perform tasks usually requiring human intelligence; examples include voice recognition and language translation; drives automation and decision-making
Driverless cars: use GPS, WiFi, and spatial sensors (e.g., LIDAR/laser) to navigate; rely on AI for safe operation and route planning
Other emerging tech in society include automation, robotics, healthcare tech, and data analytics; these technologies can improve efficiency but raise ethical and societal questions

Practical and conceptual implications

Ethical considerations: privacy (surveillance capabilities in devices), data security, job displacement due to automation, digital divide
Philosophical questions: human-technology interaction, dependency on devices, consent and governance of AI systems
Practical considerations: cost, maintenance, software licensing, compatibility, storage needs, data backups, and network reliability

Activities and questions (referenced from the chapter)

1.01 External devices: brainstorm devices and categorize as input, output, or both; note their functions
1.02 OS and software: define generic internet software vs. applications; advantages of custom-made vs. off-the-shelf software
1.03 Input/Output categorization: place devices into input or output categories; identify those that are both
1.04 ROM/RAM: answer specific questions about ROM/RAM acronyms, functions, differences, and volatile vs non-volatile memory
1.05 Interfaces: explore different user interfaces (menu-based, form-based, natural language); discuss which interfaces suit which users and tasks
Extension Activity 1.01: further exploration of microprocessor usage in home devices
1.06 Discussion: analyze advantages/disadvantages of tablets vs smartphones vs laptops vs desktops; contextual usage scenarios

Key terms (glossary highlights)

Motherboard: main PCB that allocates power and allows communication between CPU, RAM, and other hardware components
CPU (Central Processing Unit): executes instructions and performs calculations
ALU (Arithmetic Logic Unit): performs arithmetic and logical operations, including bit-shifting
CU (Control Unit): interprets instructions and coordinates operations across the system
Cache: small, fast memory for storing frequently used data/instructions
RAM (Random Access Memory): volatile main memory used for data/in-use; loses contents on power-off
ROM (Read-Only Memory): non-volatile startup memory containing essential instructions
BIOS (Basic Input/Output System): firmware that initializes hardware and boots the OS
Device drivers: software that enables operating systems to communicate with hardware peripherals
Linker: combines program modules into a single executable
Compiler: translates source code into executable instructions for the computer
Utilities: system software that maintains/analyzes/configures the computer (e.g., antivirus, defragmenter, backup tools)
Bootloader: small program that starts when the computer is powered on to load the OS
Hypervisor: software that creates and manages virtual machines, partitioning CPU/RAM among them
CLI (Command Line Interface): text-based interface for entering commands
GUI (Graphical User Interface): graphical interface using windows/icons/mouse interactions
WIMP: Windows, Icons, Menus, Pointers (a common GUI paradigm)
Backing store/External storage: secondary storage devices used to store programs and data when the computer is off

Notable figures and concepts to remember

Figure 1.01: Typical computer system (hardware + software overview)
Figure 1.02: Internal hardware components (CPU, RAM, motherboard, drives, expansion cards, cooling)
Figure 1.03: Hard drive (how data is read/written by magnetic heads)
Figure 1.04: Command line interface example (prompt and commands)
Figure 1.05: ROM and RAM diagram (start-up vs data in use)
Figure 1.06: GUI illustration (windows, icons, mouse, pointer)
Figure 1.07: Portable computing devices (laptop and tablet)
Figure 1.08: Driverless car concept (GPS, WiFi, sensors)

Formulas and explicit representations (LaTeX)

Byte definition: $ext{byte} = 8 ext{ bits}$
Example data representation: $01000001 ightarrow ext{A}$ , $01000010 ightarrow ext{B}$
RAM volatility: $ext{RAM is volatile} ightarrow ext{contents are lost when power is removed}$
ROM non-volatility: $ext{ROM is non-volatile} ightarrow ext{contents persist without power}$

Connections to foundational principles and real-world relevance

Hardware/software co-design: both must be present for a computer system to function; software cannot run without hardware, and hardware needs software to be useful
Abstraction layers: OS abstracts hardware complexity, providing a platform (GUI/CLI) for applications
Performance considerations: CPU design (ALU, CU, cache) and memory hierarchy (RAM vs ROM) influence system speed
Data representation: binary with bits/bytes is foundational to computing; understanding this aids in debugging, programming, and performance tuning
Emerging technologies: AI and autonomous systems (e.g., driverless cars) reshape how we interact with devices and necessitate new ethics/regulations

Cross-references to prior knowledge and real-world relevance

Networking concepts (WiFi, 3G/4G) connect devices and enable shared resources (printers, files) across home/school environments
File management and data integrity relate to utilities and backup strategies; proper RAM/ROM management affects boot reliability and system stability
Custom software vs off-the-shelf software: organizational needs often drive bespoke solutions (payroll, accounting, stock control) vs standardized tools

Summary takeaways

Computers are built from hardware (tangible parts) and software (instructions)
The CPU, RAM, ROM, storage, and I/O devices form the core of a computer system
Operating systems provide interfaces (GUI/CLI) and manage hardware resources, drivers, and utilities
Various computer forms (desktop, laptop, tablet, smartphone) serve different use cases; portability, power, and connectivity vary
Emerging technologies (AI, autonomous systems) are transforming everyday life, with ethical and practical implications
Understanding data representation (binary, bits, bytes) and memory types (volatile vs non-volatile) is essential for deeper comprehension of how computers work

Quick review prompts

What are the two main components of any computer system?
How do RAM and ROM differ in terms of volatility and purpose?
What roles do the ALU, CU, and cache play in the CPU?
What is the difference between system software and applications software?
What are BIOS and the bootloader, and how do they relate to startup?
Why might an organization choose custom-made software over off-the-shelf solutions?
What are the advantages and disadvantages of tablets, smartphones, laptops, and desktops for various tasks?
How do GUI and CLI differ in use and accessibility? Which scenarios favor each?

Extension activities (from the chapter)

Investigate home microprocessors in everyday devices and discuss how they optimize functionality
Explore additional user interface types (natural language, menu-based, form-based) and their appropriate contexts
Examine the concept of virtual machines and how hypervisors allocate CPU/RAM across VMs