Paper 1

• define hardware (give examples)

  physical components of a computer

  CPU, monitor, mouse
• Name the functions of all CPU components

  1) Control Unit - sends Control and timing signals to direct the operation of the CPU & decodes instructions as part of the F-E cycle

  2) ALU (Arithmetic and Logic Unit) - performs simple calculations and logical operations

  3) Registers - temporary storage space for one instruction or address - different registers are used throughout the F-E Cycle

  4) Cache memory- used to temporarily store data that is frequently accessed (faster to access than RAM)
• define software (give examples)


  programs that run on a computer

  utility software, Microsoft
• Define computer


  any programmable machine or electronic device which takes an input, processes the data to deliver an output

  --> computers are general purpose
• What does CPU stand for

  Central Processing Unit
• What is the purpose of the CPU and which part of the body is it likened to?

  To process data and instructions through the repetition of the Fetch-Decode-Execute Cycle

  Likened to the brain of the a computer
• What are the four CPU components

  1) Control Unit / CU

  2) ALU / Arithmetic and Logic Unit

  3) Registers : PC, MAR, MDR, CIR, ACC

  4) Cache memory
• Define the term 'Computer architecture'

  the way a computer is designed and structured
• What is an embedded system (give examples)

  A computer system built into a larger machine to provide a means of control

  - Performs a specific pre-programmed task stored in RAM / are built for one purpose

  Calculator; Washing machine; Toaster; Microwave
• define input devices


  send data/ instructions into a computer
• define output devices


  devices that receive information from the computer
• What is the function of the hard drive

  for permanent storage - has long lasting memory
• State the function of the expansion slots


  used to upgrade a computer- provides it with an increase in storage
• state the function of the heat sink

  draws heat away from the CPU
• Where does the CPU get instructions from?

  Input devices : mouse / keyboard

  Program instructions : Open programs running
• How do the CPU and RAM (main memory) work together?

  CPU fetches the instructions from RAM

  CPU then decodes the instruction and then executes

  This is known as the FDE Cycle
• What affects the performance of the CPU?

  THE 3 C's:

  - Clock speed

  - Cores

  - Cache
• What is clock speed?

  It is a measure of how many FDE cycles can be completed per second (Hertz)
• What is clock speed measured in?

  Hertz (Hz), usually Ghz
• What is an advantage of increasing clock speed?

  It improves performance:

  The higher the clock speed, the more FDE cycles per second --> better performance as more instructions can be processed each second
• What is meant by overclocking?


  Overclocking = when a computers clock speed is increased to above its recommended rate
• List both positives and negatives of overclocking

  + makes computer perform faster

  - Can damage the machine and lead to overheating
• What is meant by underclocking?

  Underclocking = when the computer's clock speed is decreased lower than its recommended rate
• List both positives and negatives of underclocking

  + increase the lifespan of the machine

  - make it perform slower
• state the purpose of the motherboard

  keeps the different factors of the computer together
• What is a CPU core

  A core = complete set of CPU components (the control unit, ALU, registers

  --> Each core is able to perform its own FDE cycle
• What is meant by a multi-core CPU. and list examples

  Multi-core CPU = has more than one set of components within the same CPU

  - Single-core processor (1 core)

  - Dual-core processor (2 cores)

  - Quad-core processor (4 cores)

  - Octa-core processor (8 cores)
• How does the number of cores improve CPU performance

  A computer with more cores will have higher performance as it is able to process more instructions at once
• What are the limitations of having more cores

  - One core may be waiting for another to finish processing, meaning performance might not increase at all

  - Some software isn't written to make use of multiple cores, so it won't run any quicker
• What is the purpose of cache?

  Cache = fast memory

  - temporary storage for frequently accessed data
• How does cache improve perforance?


  - closer to the CPU than RAM, meaning it provides data and instructions to the CPU much faster

  - repeatedly used instructions can be stored and accessed much faster
• What is the limitation of cache memory?

  Costly, so most computers only have a small amount
• A CPU has 2.3Ghz dual core. How many instructions is this in one second?

  2.3 billion per second
• Mr Moore is looking at two computers; one has a single core processor and the other has a dual core processor. Explain why having a dual core processor might improve the performance of the computer.

  A CPU core is the complete set of components in the CPU, and each individual core performs its own FDE Cycle. By having 2 cores instead of 1, more instructions will be able to be processed per second, therefore increasing the computers overall performance.
• Define what is meant by an embedded system

  An embedded system = a computer system built into another machine in order to control it with specific pre-programmed instructions for a specific purpose - in RAM
• Identify 3 example of an embedded system

  Microwave

  Toaster

  Washing machine
• Mr Moore's computer has an operating system. Mr Moore thinks his computer is an embedded system. State whether Mr Moore is correct or incorrect, justifying your choice
• What is meant by Von Neumann architecture?

  Von Neumann invented a computer that stores both program instructions and data in the same memory (RAM), and it travels on pathways called 'buses'

  --> most common architecture of most modern day computers
• Identify the registers of the CPU

  Program Counter; Memory Address Register; Memory Data Register; CIR; Accumulator
• Explain the purpose of CPU Registers and they work in the FDE Cycle

  1) Program Counter (PC) = tracks RAM address of the next instruction to be fetched / processed, copies this to MAR, then the PC register increases by 1

  2) Memory Address Register (MAR) - tracks RAM address of instruction that's to be fetched from RAM

  3)Memory Data Registers (MDR) - stores instruction transferred from RAM to CPU

  4) Current Instruction Register (CIR) - stores information from MDR that is about to be decoded or executed

  5) CIR --> ACC

  Instruction in CIR is decoded and executed. Any result of the execution is stored in the Accumulator register