Lecture Notes: Hardware and Computer Science Fundamentals

Memory and Storage

Memory Cache

• High-speed memory external to the processor.
• Stores data that the processor will need again.

Primary Memory

• Directly accessed by the CPU.
• Contains RAM and ROM.
• Allows temporary storage of applications and services.

RAM (Random Access Memory)

• Faster access time compared to secondary devices.
• Volatile memory; data can be changed by the user/computer.
• Stores data or part of an application/OS temporarily.
• Larger RAM = faster computer operation.

ROM (Read Only Memory)

• Permanent, non-volatile memory.
• Cannot be written to or changed.
• Stores data needed when the computer is turned on, like BIOS.

Embedded Systems

• Miniature computer systems within a larger system.
• Perform specific functions, unlike general-purpose computers.

Secondary Storage Devices

• Not directly accessible by the CPU.
• Non-volatile memory, larger than primary memory.
• Slower data access time compared to primary memory.

Principle Operations of Hardware Devices

Laser Printer

• Uses a laser beam to draw an image on a photosensitive drum.
• Toner sticks to the drum image, transferred to paper, and fused with heat.

3D Printer

• Builds objects from a digital file by adding layers of material.

Microphone & Speaker

• Microphone: Converts sound waves into electrical signals.
• Speaker: Converts electrical signals into sound waves.

Storage Devices

• Magnetic Hard Disk: Data encoded as magnetic patterns on platters.
• Solid State Memory: Uses NAND-based flash memory.
• Optical Disc Reader/Writer: Uses lasers to read/write data on discs.

Touchscreen

• Input and output device with capacitive and resistive types.
  • Capacitive: Good visibility, multi-touch capability.
  • Resistive: Inexpensive, allows gloved/stylus input.

Virtual Reality Headset

• Simulates a 3D environment, allowing movement via head/controller.

Buffers

• Temporary storage to balance input/output speeds.

Sensors

• Input devices that measure physical properties.
• Convert analogue data to digital using ADCs.

Processor Fundamentals

von Neumann Architecture

• CPU accesses memory directly.
• Programs stored in memory can be executed sequentially.

CPU Components

• Control Unit (CU): Manages data flow within the CPU.
• Arithmetic Logic Unit (ALU): Performs calculations and logical operations.
• Registers: High-speed storage within the CPU.
• Cache: Stores frequently used instructions.

System Bus

• Transfers data between computer components.
• Types: Address bus, data bus, control bus.

Factors Affecting CPU Performance

• Number of cores, bus width, clock speed, cache size.

Overclocking

• Increasing CPU clock speed to enhance performance.
• Risks include overheating and instruction execution issues.

Assembly Language

• Machine code is the only language a CPU can understand.
• Assembly language uses mnemonics for easier programming.

Addressing Modes

• Absolute, direct, indirect, indexed, immediate, relative, symbolic.

Bit Manipulation

• Shift operations: logical, arithmetic, cyclic shifts.
• Used in monitoring and control systems for flag management.

Ethics and Ownership

Computer Ethics

• Intellectual property rights, privacy issues, effect on society.

Software Copyright and Licensing

• Software is copyright-protected; unauthorized copying is illegal.
• DRM and software licenses control software usage and distribution.

Artificial Intelligence (AI)

• AI impacts public perception, transport, criminal justice, advertising.

Databases

Relational Database Modelling

• Use of tables, tuples, attributes, primary and foreign keys.

Normalization

• 1NF, 2NF, 3NF: Ensures data integrity and reduces redundancy.

SQL Commands

• DDL and DML for database creation, querying, and maintenance.

Networks and Communication

Networking Models and Topologies

• Client-server and peer-to-peer models.
• Bus, star, mesh, and hybrid topologies.

Networking Hardware

• Switches, routers, NICs, WAPs, repeaters.

Internet and WWW

• Difference between internet and WWW.
• Use of IP addresses and DNS.

Security, Privacy, and Data Integrity

• Importance of data security and measures such as encryption, firewalls.

Threats to Security

• Malware, spyware, phishing, hacking, and their prevention.

System Software

Operating Systems

• Provide user interfaces and manage resources.

Language Translators

• Convert high-level languages to machine code.
• Types: Assemblers, compilers, interpreters.

Security Tools

• Use of firewalls, anti-malware, digital signatures to protect data.