Computer Hardware Fundamentals Quiz

Von Neumann Definition

• Programs (commands) and data are stored together in memory.
• The first piece of information is always a command, followed by data.

Harvard Definition

• Programs (commands) and data are stored separately.
• Information from instruction memory is a command, and data memory contains data.

The Motherboard

• The motherboard is the computer's backbone.
• It's a printed circuit board (PCB).
• It contains buses (electrical pathways) connecting electronic components.
• Components can be soldered or added through sockets, expansion slots, and ports.

The Modern Motherboard

• BIOS is a boot program that configures the motherboard and chipset devices.

CISC vs RISC CPUs

• CISC (Complex Instruction Set Computer):
  • Reduced code size.
  • More efficient memory use.
  • Slower execution.
  • More complex design.
  • Higher power consumption.
• RISC (Reduced Instruction Set Computer):
  • Simpler instructions.
  • Faster execution.
  • Lower power consumption.
  • More instructions needed.
  • Increased memory usage.
  • Higher cost.

The System Bus Model

• The system bus is a shared pathway for component communication.

• Subunits of a computer system are:

  • CPU
  • Memory
  • Input/Output (I/O)

• The ALU and control unit are combined into one functional unit (CPU).

• Input and output units are combined into a single I/O unit.

• Includes:

  • Data Bus
  • Address Bus
  • Control Bus
  • Power Bus

Fetch and Execute Cycle

• CPU reads commands from memory (Read cycle).
• CPU reads the command's address from memory (Read cycle).
• CPU does the command (Execute cycle).
• Cycles repeat.

CPU Components

• Central Processing Unit (CPU):
  • Two major components:
    • Control Unit
    • Arithmetic Logic Unit (ALU).
  • Special registers for processing operations.
  • Registers are high-speed memory locations.

CPU Components + Registers

• Components include a Control Unit, Arithmetic/Logic Unit, and Registers (PC, CIR, MAR, MDR, AC).

The Control Unit

• Coordinates and controls all computer operations.
• Monitors hardware connected to the system.
• Manages input and output of data.
• Controls data flow within the CPU.

Arithmetic Logic Unit (ALU)

• Performs arithmetic (addition, subtraction, multiplication, division) and logical (comparison) operations on data.

The CPU Components - Registers

• Program Counter (PC):

  • Holds the address of the next instruction to be executed.
  • Located in the Control Unit.
  • Incremented after each instruction fetch.

• Current Instruction Register (CIR):

  • Holds the current instruction to be executed.

• Memory Address Register (MAR):

  • Stores the memory address of the current instruction or data to be fetched from memory.

• Memory Data Register (MDR):

  • Stores the actual instruction or data that has been fetched from memory.

The CPU Components - Buses

• A bus is a set of parallel wires connecting independent components to pass signals.
• Types of buses:
  • Data Bus
  • Address Bus
  • Control Bus
• These buses transmit signals between the CPU, memory, and input/output devices.

The CPU Connections

• Electrical wires connecting the CPU are grouped into three buses:
  • Address Bus (16, 32, 64, 128 bits)
  • Data Bus (8, 16, 32, 64 bits)
  • Control Bus (signals like read/write, clock, DMA, interrupts, etc.)

How does a CPU work?

• CPU processes instructions using a Fetch/Execute cycle.
• Program/data stored externally is transferred into the CPU (via the bus).

Interface Standards - ISA

• Industry Standard Architecture (ISA).
• Extension of FSB.
• Address and data bus in a common connector form.

Interface Standards - PATA

• Ultra ATA data cable (ribbon), which allows you to connect two devices on the same IDE controller (jumper).
• Maximum speed is 133MHz with 16 bits.

Interface Standards - SATA

• Serial ATA (SATA) replaced PATA.
• Serial protocol to improve data speed and allow different data widths.
• Increased bandwidth and transfer rates over PATA.

Interface Standards - EISA

• Extended Industry Standard Architecture (EISA) is a 16-bit bus standard.

Interface Standards - PCI

• Peripheral Component Interconnect improves speed, uses the double or quadruple bit-width.
• Windows 95-11 support this by automatic setting up hardware.

Interface Standards - AGP

• Advanced Graphics Port (AGP).
• To handle graphics related data that was causing problems using PCI.
• Speed improvement on existing PCI standard.

Interface Standards - PCIe

• Peripheral Component Interconnect Express (PCIe).
• Replaced most other standards.
• Newer serial architecture allows multiple channels to work concurrently supporting x4, x8 and x16.

Variations of Drives

• Solid State Hard Drive (SSHD))
• Solid State Drive (SSD)
• Best of both worlds (magnetic and solid-state).

Choosing a Storage Drive

• Data transfer time.
• Rotational speed.
• Onboard Cache.
• Form factor.
• Interface standard.
• Data storage size.
• Cost.
• Lifetime.

How are CPUs made?

• CPUs are made of silicon doped with group 3 & 5 materials.
• Combination of semiconductor materials produces transistors (electronic switches).
• Transistors are combined to create more complex devices for logical operations.

Basic Building blocks

• Logic elements are represented as 0s and 1s in truth tables.
• Basic logic gates include:
  • AND
  • OR
  • NOT
  • NAND
  • NOR
  • XOR

SSI, MSI, VLSI, LSI, Devices

• Building blocks are combined in increasing complexity to create Small, Medium, Large, and Very Large scale components.

Types of Memory

• ROM: Read-Only Memory.
• RAM: Random Access Memory (SRAM, DRAM).
• EPROM: UV light erasable ROM.
• E2PROM: Slow High Voltage Erasable ROM.
• Flash Memory: Low voltage Erasable ROM

Memory Hierarchy

• Data is stored in hierarchical order from fastest to slowest and largest to smallest capacity.
• Registers, Cache, Main Memory, Flash Disk, etc.

Virtual Memory

• CPU sends virtual addresses to the MMU.
• The MMU converts virtual addresses to physical addresses and sends them to the memory.
• Allows programs to use more memory than physically available.

Memory - Design and Performance

• Factors to consider in memory design:
  • Access time
  • Data bus size
  • Cost per Gigabyte
  • Cooling Requirements
  • Availability
  • Compatibility with motherboard.

RAMBUS

• Significant changes include:
  • New protocol-based interface for DDR memory.
  • Impedance matching for reduced electronic noise.
  • Lower voltage levels for faster operation, so hence lower time for the threshold to be reached.

Light and Colour

• Combining lights of different wavelengths creates different colours.
• Primary colours are red, green, and blue (RGB).
• Combining light to create white is additive colour mixing.

Pixels and Colour displays

• Digital images are discrete areas of specific colours (pixels).
• Pixels consist of areas for each primary colour (RGB).
• Colour determined by the glow of red, green, and blue areas.
• Dot pitch is the distance between pixels

Display standards

• Standards define video display modes, encompassing resolution, colours, and pixel colour representation.
• Important standards include VGA, SVGA, XVGA, WXGA, HDMI, Ultra HDMI.

Terminology

• Resolution: Total number of pixels on the screen (horizontal x vertical).
• Refresh rate: Frequency of repainting the screen.
• Dot frequency: Number of pixels output per second.
• Aspect ratio: Ratio of width to height
• Display size: Diagonal of the display.
• Colour depth: Number of bits used to represent colours (8-bit, 16-bit, 24-bit etc...).

Pixel data to RGB colour mapping

• Pixel data is represented by numbers for each RGB colour.
• 24-bit colour depth uses three 8-bit values for each colour. -16-bit colours depths uses 5,6,5 bits to give 65536 colours.

Components of a Liquid Crystal Display (LCD)

• Backlight Unit
• Horizontal Polarising Filters
• Active Matrix TFT Array.
• Liquid Crystal
• RGB Colour Filters
• Vertical Polarising Filters

Simple graphics card components and operation

• CPU processes video data.
• Data sent to Image Frame Buffer.
• RGB numerical values sent to DAC.
• DAC converts RGB values to voltage levels.
• Display device synchronised via dot clock.

Speed/Memory Improvements: Coprocessors & GPUs

• Graphics Processing Units (GPUs) are dedicated to graphics related operations, speeding up the process as compared to the CPU.
• Calculating pixel colour values faster to represent images.

Lets shrink the data

• Data compression improves image throughput by reducing data amounts.
• Compression types include:
  • Lossy, where some quality is lost during decompressing.
  • Lossless, where quality is retained during decompressing.

Floating Point Numbers

• Floating point numbers use a format to represent numbers with decimal values and stored in memory.
• Sign bit (0 is positive, 1 is negative).
• Exponent (with a bias).
• Mantissa (fractional part).
• Stored memory is in little endian format, to access the least significant bit first

Using Text

• ASCII (American Standard Code for Information Interchange):
• Codes to represent text, enabling the use of characters and control codes on computers.
• Telex: (1926): Used for text communication before ASCII.

Extended ASCII and Unicode

• ASCII expanded to include more characters, enabling the inclusion of Europe-specific characters.
• Unicode provides a larger character set, with more characters and symbols from different languages.
• Different unicode formats exist such as UTF-64 ,UTF-128 etc .

Computer Misuse Act 1990

• UK law to govern lawful access to computer data.
• Illegal activities include unauthorised access, access with criminal intent, modifications, and making tools for misuse.

Data Protection Act 1998

• Sets guidelines to handle personal information.
• Appropriate measures are taken to safeguard during examinations. – Exemptions are allowed in activities like detecting or preventing crimes or safeguarding national security.

Environmental Issues to Consider

• Issues with Earth's natural resources, energy consumption, waste from processing, waste from old technology, creation of a disposable society, and the environmental benefits from computing.