Unit 4.1 - Hardware

• The CPU carries out Arithmetic and Logical operations, executes instructions, and controls the transmission of data between input and output devices and memory
• Von-Neumann Architecture refers to the structure of most modern CPUs
• Parts of a CPU include the Control Unit, Arithmetic Logic Unit (ALU), Buses, and Registers
• Fetch-Decode-Execute (FDE) Cycle describes the process a CPU uses to process instructions
• The Von Neumann Bottleneck refers to the reduction of efficiency due to speed mismatches between memory and the CPU
• Factors affecting CPU performance include Clock Speed, Number of Cores and Cache
• Clock Speed:

  • Defines the number of FDE cycles that can be completed per second
  • Overclocking increases speed but produces more heat and reduces lifespan
  • Underclocking decreases speed but consumes less power and increases lifespan
• Number of Cores:

  • Multiple cores theoretically increase performance by allowing simultaneous instruction execution
  • In some cases, a processor may be left idle waiting for instructions, slowing down the CPU
• Cache:

  • Fast, volatile storage on the CPU
  • Stores frequently used instructions and data to reduce the drop in clock speed when fetching data
• Parallel Processing:

  • In Multicore systems, cores work together to perform tasks simultaneously
  • Can significantly reduce program execution time if software is designed for parallel processing
• Amdahl’s Law defines the maximum possible speed-up of a single program due to parallelization. With infinite cores, the speed of a program will be limited to the portion of the program executed sequentially.
• Optical Character Recognition (OCR):

  • Converts printed media into editable text documents
  • Can be used to digitise books or documents
  • Sometimes characters are not recognised well, and the produced document should be proofread
• Optical Mark Recognition (OMR):

  • Used in multiple-choice documents where a person checks an answer
  • The device detects the dark marks made and, as the form is predefined, can determine the option selected
• Magnetic Ink Character Recognition (MICR):

  • Used to print cheques
  • Device only detects the iron oxide ink, so even if the information is written over, only the information written using the special ink is detected
• Touch Screens:

  • Used widely in smartphones, tablets, ATMs, and more
  • Intuitive and easy to use, allowing a user to simply touch a screen to perform an action, removing the need for a keyboard or mouse