Hardware: A collective term for the physical components of the computer system. (2023)

The central processing unit (CPU) [2024]

• Process all data/instructions

• Microprocessor (does specific tasks, work of a CPU on a smaller scale, embedded systems)

• To run the fetch-decode-execute cycle (when an instruction is processed)

• 
  

• Fetch stage

  • Data instructions input stored in RAM

  • PC stores an address of the next instruction to be processed

  • Address transported from PC to MAR using Address Bus

  • The instruction is sent to MDR using Data Bus

  • MDR sends it to CIR (using Data Bus), CIR is part of CU

  • PC is incremented by 1

• Use of MAR (Stores addresses of next instruction/data to be fetched // where data is to be written to) (2023)

• Use of MDR (Stores data that has been fetched/to be written to memory) (2023)

• Instruction set (list of all the machine code commands)(2023)

• Registers (To store / holds data / address / instruction temporarily and allow immediate access to data during the FDE cycle)(2023)

• Busses

  • Address bus

    • Transmit / carries addresses between components in the CPU

  • Data bus 

    • Transmit / carries data between components in the CPU

  • Control bus

    • Transmits control signals from the control unit to other components in the CPU

• Decode stage (2024)

  • CIR/CU receives the instruction from the MDR // Instruction sent from MDR to CIR/CU (using the data bus)

  • Instruction is separated into opcode and operand

  • Control unit decodes the instruction (using an Instruction set (list of all the machine code commands))

• Execute stage

  • Actions like mathematical and logical calculations (using ALU-2023)

  • Interim values are stored in Accumulators (ACC)

  • The CU used the Control bus to send signals

ALU [2024]

• •  To execute instructions

  •  To perform calculations

  •  To perform logical operations

  •  To store interim results of calculations

  •  Stores/reads/writes data to/from the accumulator

Core, cache, and clock ALU

• Core

  • A single core performs one fetch-decode-execute cycle

  • Two cores (dual cores) perform two fetch-decode-execute cycles

  • Multicore allows computers to multitask

• Cache [2023]

  • Within the CPU

  • type of storage

  • temporarily stores frequently used instructions/data for quicker processing

    • • To speed up access (as it is faster to access Cache than RAM)

  • has different levels e.g. L1 – L3 

  • More cache improves performance [2024]

    •  ...because more cache means the processor can access more frequently used data/instructions faster

    • ...instead of having to access the data from the slower-access RAM

• Clock

  • Regulates the number of fetch–decode–execute cycles the CPU can perform in a second.

  • Internal Clock controlling the speed at which instructions are processed

  • Clock Speed: The maximum number of FDE cycles/instructions a CPU can perform/process/execute in a second (2023)

  • Higher the Clock speed: Increases/improves the performance // Tasks can be performed quicker/faster (because more FDE cycles/instructions can be processed in a second)

  • Speed measured in Hertz

    • 1 Hertz = one instruction per second

    • 2Ghz = 2 billion instructions a second (modern computers)

    • E.g. 2.4Ghz clock speed - The CPU completes 2.4 billion cycles/clock pulses per second (2023)

Example:

3.5GHz processor means, it can run 3.5 billion Fetch Execute cycles each second // it can execute 3.5 billion instructions each second

Embedded system (2023)

• • Performs a single/limited/dedicated function/task

  • It has a microprocessor

  • It has dedicated hardware

  • Uses firmware

  • It is normally built into a larger device/system

  • User normally cannot reprogram

  • It does not require much power

  • It is cheap to manufacture

  • Works automatically // works without human intervention

  • It is small (in size)

  • It is a real-time system

  • Example:

    • security light system

    • freezer

    • vending machine

Input devices

• • Barcode scanner

    • Description: It scans the barcode to obtain the data. Uses laser light

    • Example of Use: Used in Supermarkets (to get the price & maintaining stocks), 

  • Digital camera

    • Description: captures images in a digital format, allowing them to be stored/viewed on a computer. 

    • Example of Use: Used in photography for capturing still images and recording videos 

  • keyboard

    • Description: used to enter text and commands 

    • Example of Use: Used for typing text, entering commands, and navigating through interfaces 

  • Microphone

    • Description: converts sound waves into electrical signals that can be processed or recorded by a computer

    • Example of Use: Used in voice recognition systems, recording audio, and making voice calls. 

  • Optical mouse

    • Description: Detects movement by shining light on a surface 

    • Example of Use: Used for controlling cursor movement on computer screens. 

  • QR code scanner

    • Description: reads/scans a QR code and converts it into a string of characters that can be processed by a computer //to retrieve encoded information 

    • Example of Use: Used for mobile payments, accessing websites, and tracking inventory/databases. 

  • Touch screen (resistive, capacitive, and infra-red)

    • Description: a display that can detect the presence and location of a touch within the display area

    • Example of Use: 

    • Resistive: responds to pressure, used in industrial applications and some consumer devices.

    • Capacitive: use the electrical properties of the human body to detect, common in smartphones, tablets, and interactive kiosks.

    • Infra-red: use an array of X-Y infrared LED and photodetector pairs around the edges of the screen, found in specialized environments like outdoor displays. 

  • Two-dimensional (2D) and three-dimensional (3D) scanners

    • Description: Captures two-dimensional images or documents//Captures three-dimensional data from physical objects.

    • Example of Use: 

    • Used in document scanning, digitizing images, and capturing barcodes (2D)

    • Used in 3D modeling, virtual reality development, and quality control (3D)

Output devices

• • Actuator

    • Description:  operated by a source of energy – typically, electric current, hydraulic fluid pressure, or pneumatic pressure – and converts that energy into some kind of motion.

    • Example of Use: Used in robotics, industrial machinery

  • Digital light processing (DLP) projector

    • Description: Projects digital images or videos using microscopic mirrors

    • Example of Use: Used in movie theaters, classrooms, conference rooms, and home theaters

  • Inkjet printer

    • Description: Sprays tiny droplets of ink onto paper to create printed output

    • Example of Use: Used for printing documents, photos, brochures, and marketing materials

  • Laser printer

    • Description: uses a laser beam to create an image on a drum, which is then rolled through toner and transferred onto paper

    • Example of Use: Commonly used in office environments, for printing documents and reports.

  • Light emitting diode (LED) screen

    • Description: Displays visual output using an array of light-emitting diodes

    • Example of Use: Found in digital billboards, TVs, computer monitors, and indoor displays

  • Liquid crystal display (LCD) projector

    • Description: Projects digital images using liquid crystal panels and light bulbs

    • Example of Use: Used for presentations, movie screenings, and educational purposes

  • Liquid crystal display (LCD) screen

    • Description: Displays visual output using liquid crystal technology

    • Example of Use: Found in smartphones, tablets, laptops, computer monitors, and TVs

  • Speaker

    • Description: Converts electrical signals into sound waves 

    • Example of Use: Used for playing audio, alert sounds, music, and system notifications

  • 3D printer

    • Description: creates three-dimensional objects by depositing materials layer by layer following the object's 3D digital model

    • Example of Use: Used in prototyping, manufacturing, art, education, and medical fields

Sensors

• • Acoustic (measures sound levels. Used in security systems)

  • Accelerometer (measures vibration on cars, machines, buildings, process control systems and safety installations, acceleration forces. Used in Vehicles, Phones, earthquake monitoring)

  • Flow (amount of liquid/gas/steam flowing/moving through an environment. Used in factories, and nuclear power plants)

  • Gas (measures the concentration of the gas in the atmosphere)

  • Humidity (measures level of moisture. Used in farming, agriculture, greenhouses)

  • Infra-red(detect objects, motion and infra-red radiation. Used in security systems)

  • Level (measures amount of substance. Used in cars-oil/fuel)

  • Light (measures the presence of light/lasers. Used in automated lighting system)

  • Magnetic field (measures the presence of magnetic fields. Used in counting cars passing an area)

  • Moisture(measures amount of water in a substance/soil. Used in farming, agriculture)

  • pH(measures the acidity or alkalinity. Used to monitor pollution level in rivers/lakes)

  • Pressure(measures amount of pressure applied. Used in security systems)

  • Proximity(measures objects distance. Used in robots, self driving cars)

  • Temperature(measures temperatures. Used in air conditioning levels)

Describe how the sensor and the microprocessor work together:

• • Sensor continually sends digitised data to microprocessor

  •  Microprocessor compares data to stored value(s)

  •  If value is outside range / matches microprocessor sends signals

  •  Whole process repeats until turned off/stopped

Data Storage

Primary

• • • directly accessed by the CPU

    • Includes

      • Random access memory (RAM)

        • Volatile

        • Can be extended (increase size)

        • Stores: [2023]

          • • Currently running data

            • Currently running (application) software

            • Currently running instructions

            • Currently running parts of OS

            • Currently running utility software

      • Read-only memory (ROM)

        • Non-volatile

        • stores Bootstrap and the BIOS

        • Contents are fixed

        • Not easy to alter

        • Firmware is a type of software stored in the read-only memory (ROM) and includes the basic input-output system (BIOS) and the bootloader.[2023]

Secondary [2023]

• • not directly accessed/required by the CPU

  • For non-volatile/permanent/long-term storage of files/data

  • To store data to transfer it to another computer

    • Magnetic storage 

      • Data is stored on platters

      • (Platters) are divided into tracks and sectors

      • Has components that are spun

      • Data is read/written using a read/write arm

      • Data is read/written using electromagnets

      • Magnetic field determines the binary value

      • It is non-volatile

      • has moving parts

      • Examples: 

        • • HDD

          • Magnetic tape

          • Floppy disk

          • Magnetic strip

    • Optical storage 

      • uses lasers to create and read pits and lands

      • Examples: 

        • • CD

          • DVD

          • Blu-ray

    • Solid-state (flash memory) 

      • Semiconductor chips

      • non-volatile, means that the data is not lost when the power is turned off

      • made of transistors that are laid out in a grid.

      • Gates (NAND or NOR) are used to control the flow of the electrons through the transistors.

      • This changes the data in the transistors from 1 to 0, or from 0 to 1.

      • uses NAND or NOR technology. 

      • Transistors are used as control gates and floating gates

      • No moving parts

      • No magnetic properties

      • Can be used in smartphones to (2024) :

        • To store data/files permanently

        • To allow software to be downloaded/installed on the smartphone //

        • To store user files

        • For the creating of virtual memory

      • Examples: 

        • • SSD

          • USB drive

          • SD card

          • RAM

  • Virtual Memory

    • • Created for temporary use

      • Extension to RAM

      • The hard drive is partitioned to create virtual memory

      • When RAM is full

        • • pages of data that are not required

          • are transferred from RAM to virtual memory

      • When the data is required again the pages are transferred back to RAM

  • Cloud Storage [2023]

    • •  A collection of servers that store data in a remote location // that allows data to be accessed remotely using an internet connection

      • data can be accessed from any location (employees can work from anywhere with a connection)

      • hardware is owned/maintained by a third party (no responsibility for maintenance, Security)

      • Can increase the storage needed easily (without needing to buy new hardware)

      • No need to house the hardware physically

      • Cloud system will back up the data on its own

Differences between primary storage and secondary storage.[2023]

• • • •  Primary storage is directly accessible by the CPU whereas secondary storage is not directly accessible by the CPU

      •  Primary storage stores the data that is currently in use/for booting the system whereas secondary storage stores the user’s files/data/operating system/application software

      •  Primary storage normally has a small capacity whereas secondary storage normally has a larger capacity

      •  Some parts of primary storage are volatile whereas secondary storage is non-volatile

      •  In some parts of primary storage, the data cannot be changed whereas data in secondary storage can be changed

      •  Primary storage has faster access speeds to data whereas secondary storage has slower access speeds to data

Differences between Solid State and Optical storage.[2024]

• • • •  Solid-state has no moving parts, optical does have moving parts

      • Solid-state is faster to access data, optical is slower to access data

      • Solid-state uses less power to operate, optical uses more power to operate

      • Solid-state runs quietly, optical makes more noise

      • Solid state is more durable/robust, optical is less durable/robust

      • Solid state storage has a large storage capacity, optical has a much smaller limit to its storage capacity

      • Solid-state is more expensive per GB of data, optical is cheaper per GB of data

      • Solid-state stores data onto silicon chips/transistors using logic (floating/control/NAND/NOR) gates to control the

      • movement of electrons, optical stores data by using lasers to burning pits and lands onto a disk

Network Hardware

• • Basic Hardware to create a Network:

NIC (Network Interface Card)

• • • component in the computer that is needed to access a network (2023)

    • Wired/cabled NIC or Wireless NIC (latest)

    • Each NIC given MAC address

      • MAC Address (address that is allocated to the component by the manufacturer, which is used to uniquely identify the device)

        • Represented in 12-digit Hex, separated by a Colon/Dash 

        • format MM:MM:MM:SS:SS:SS or MMMMMM-SSSSSS.

        • first 6 digit-Manufacturer ID

        • last 6 digits- Serial ID

Router

• • Reads each data packet

  • Finds destination address using IP addresses

  • forward packets to the correct destination

  • Can assign IP addresses to each device

  • Types of IP Addresses

    • IPv4 [2023]

      • 32 bits (4 sets/groups of numbers)

      •  It is denary based (with numbers between 0 and 255). Example: 192.168.32.36

      • separated by dots

      • Unique address

      •  Can be static or dynamic

      •  Can be public or private

      •  It contains the network prefix and the host number

      • still used

    • IPv6 [2024]

      • 128 bits// 16 bytes

      • Uses Hex characters//Hexadecimal

      • Separated by colons

      •  Characters in groups of 4

      •  Has 8 groups of characters

      •  Double colons can be used for sets of (consecutive) zeros (only once)

  • Static & Dynamic addresses

    • Most devices have dynamic IPs

    • Dynamic IPs can change each time the device is connected to the network (2023)

Transmission media

• • physical interface

  • cables like twisted pair cables, coaxial cables, and fiber optic cables