Chapter 4

Components of the System Unit 2022

  • System Unit

    • The system unit is a crucial part of a computer that houses the primary devices that perform operations and produce results for complex calculations.

    • It includes components such as:

    • Motherboard

    • CPU (Processor)

    • RAM (Memory)

    • Various other components

    • The system unit is often referred to as a computer case, chassis, or tower.

    • Typical materials used for computer cases include:

    • Steel

    • Aluminum

    • Plastic

Main Components of a System Unit

  • Key components found in desktop personal computer system units:

    • Motherboard

    • Processor (CPU)

    • Memory (RAM)

    • Adapter Cards

    • Buses (data pathways)

    • Power Supply and Batteries

Motherboard

  • Definition:

    • A motherboard is a printed circuit board containing the principal components of a computer or another device, featuring connectors for additional circuit boards (techopedia.com, 2022).

    • It may also be referred to as:

    • System board

    • Main board

    • Base board

    • Logic board

  • Main Parts of a Motherboard:

    1. Memory module

    2. Processor socket

    3. BIOS (Basic Input/Output System) and CMOS (Complementary Metal-Oxide-Semiconductor)

    4. Expansion slot

    5. Input/Output ports

  • Uses of Motherboard:

    • Provides logical layout for processing components.

    • Circuit board pathways, known as buses, facilitate data transfer among computer components.

    • Enables connection for various internal and external components (Banger, 2019).

Processors

  • Definition:

    • The processor, or central processing unit (CPU), is a complex integrated circuit primarily responsible for converting input data into meaningful output information (Campbell et al., 2020).

  • Processor Cores:

    • A processor core is a unit within the processor with circuitry necessary to execute instructions.

    • It receives instructions from computing tasks, utilizing clock speed to process this information quickly.

    • Processors with multiple cores are referred to as multi-core processors.

  • Clock Speed:

    • The clock speed measures how fast the processor can execute instructions, enabling the completion of tasks more quickly.

    • Clock speeds are measured in:

    • Megahertz (MHz)

    • Gigahertz (GHz)

    • A cycle is the smallest measurable time unit for a process.

    • CPU efficiency is quantified by instructions per cycle (IPC).

  • Components of a Processor:

    1. Control Unit: Manages the flow of instructions within the processor.

    2. Arithmetic Logic Unit (ALU): Performs arithmetic and logical operations.

    3. Processor Operations:

    • For each instruction, a processor executes a machine cycle comprised of four basic operations:

      1. Fetch

      2. Decode

      3. Execute

      4. Store

  • Leading Manufacturers:

    • Prominent manufacturers of personal computer processor chips include Intel and AMD.

    • Top 5 processors based on TechRadar information:

    • Intel Core i9-12900K

    • AMD Ryzen 9 5900X

    • Intel Core i5-12600K

    • AMD Ryzen 3 3100

    • AMD Ryzen 7 5800X

  • Heat Management for Processors:

    • Processor chips generate heat that can result in malfunctions or failures.

    • Additional cooling methods include:

    • Heat sinks

    • Liquid cooling technology

    • Cooling pads

Memory

  • Definition:

    • Memory is composed of electronic components that store instructions waiting to be executed by the processor, data required by those instructions, and the results from processing the data.

  • Memory Functions:

    • Memory is responsible for storing three basic categories of items:

    1. Operating system and other programs

    2. Applications

    3. Data being processed and resulting information

  • Types of Memory:

    1. Volatile Memory:

    • Temporary storage that loses its contents when power is turned off.

    • Example: RAM.

    1. Non-Volatile Memory:

    • Permanent storage that retains its contents when power is removed.

    • Examples: ROM, flash memory, and CMOS (Campbell et al., 2020).

  • Random Access Memory (RAM):

    • RAM is the storage area for temporarily holding open applications and document data while the device is powered on.

    • The operating system allocates data and instructions to memory during processing.

    • Frequently used instructions and data are stored in a cache to speed up processing time (Campbell et al., 2020).

  • Types of RAM:

    1. SRAM (Static RAM):

    • Uses 6-transistor memory cells to store data.

    • Typically used as cache memory for processors and is not user-replaceable.

    1. DRAM (Dynamic RAM):

    • Utilizes pairs of transistors and capacitors to store data.

    • Generally more affordable than SRAM but slower; replaceable, making it suitable for upgradable memory modules.

  • Read-Only Memory (ROM):

    • ROM stores permanent data and instructions that cannot generally be modified.

    • Found in computers, mobile devices, and peripheral devices like printers (Campbell et al., 2020).

  • Types of ROM:

    1. PROM (Programmable Read-Only Memory):

    • A blank version of ROM that can be programmed only once.

    • Once programmed, the data cannot be erased or rewritten.

    1. EPROM (Erasable Programmable Read-Only Memory):

    • Allows for multiple programming cycles, using UV rays to erase existing data.

    • Features a quartz window for UV exposure; wears out after approximately 1000 erasures.

    1. EEPROM (Electrically Erasable Programmable Read-Only Memory):

    • Allows for modifications and rewrites thousands of times without special equipment.

    • Programmers can write and rewrite programs without needing to disassemble the ROM card.

Adapters

  • Definition:

    • An adapter card, also known as an expansion card, add-on card, expansion board, or interface adapter, provides additional capabilities to a computer.

    • It is a printed circuit board that fits into an expansion slot on the motherboard (computerhope.com, 2021).

  • Expansion Slot:

    • An expansion slot is an installation point for a hardware expansion card.

    • Also known as a bus slot or expansion port, with Plug and Play capabilities allowing for automatic recognition of peripheral devices.

  • Types of Adapter Cards:

    • Modem Card:

    • Enables phone line connection for dial-up internet service.

    • Video Capture Card:

    • Connects to video cameras for video signal capture and streaming.

    • TV Tuner Card:

    • Allows connection of cable TV signals, enabling watching and recording live television.

    • NIC Card (Network Interface Card):

    • Also known as an Ethernet card, it enables network connections.

    • Sound Card:

    • Facilitates audio production for speakers and headphones, also known as audio output devices.

    • MIDI Card:

    • Standard for digitally representing and transmitting sounds, allowing connections to musical instruments.

    • Video Card:

    • Processes images and video; often used by gamers for enhanced performance compared to integrated graphics.

Buses

  • Definition:

    • A bus is an electronic channel allowing communication between the CPU and various devices inside or attached to a computer.

  • Bus Width:

    • The bus width determines the speed of data transmission.

  • Word Size:

    • The word size indicates how many bits the processor can process at a time (Campbell et al., 2020).

  • Types of Buses:

    1. System Bus:

    • Connects the processor to the main memory (RAM).

    1. Backside Bus:

    • Connects the processor to the memory cache.

    1. Expansion Bus:

    • Connects the processor to peripherals.

Power Supply and Batteries

  • Definition:

    • The power supply or laptop AC adapter converts AC power from wall outlets to DC power for computer use.

  • Power Sources for Mobile Devices:

    • Mobile computers may run using either a power supply or rechargeable batteries.

    • Commonly used batteries include lithium-ion ones.