1.1

• A computer device is an electronic device which:

  takes input

  processes data

  delivers output
• what is the purpose of the CPU?

  to fetch, decode and execute instructions
• how does a CPU fetch?

  fetching the next instruction from main memory (RAM)brings the instructions back into the CPU.
• how does a CPU decode?

  inspects the instruction and works out what it is that needs doing.
• how does a CPU execute?

  • carries out the instruction this could cover many things such as:
  • going back into the main memory and grabbing some data
  • performing a calculation
  • storing information back into main memory
• what does the CPU consist of?

  arithmetic logic unit (ALU), control unit (CU), Cache, registers
• what is the Arithmetic Logic Unit (ALU)?

  performs calculations and logical decisions.
• what is the Control Unit (CU)?

  sends signals to control how data moves around the CPU.
• what is the cache?

  provides fast access to frequently used instructions and data.
• what is the registers?

  Tiny, super fast pieces of onboard memory inside the CPU each with a specific purpose.
• what does the Von Neumann architecture consist of?

  Control Unit (CU), Arithmetic and Logic Unit (ALU)Memory unit (RAM), Inputs and Outputs
• what are the instruction data AND program data stored as?

  in the same memory in binary form
• what concept is the Von Neumann architecture based on?

  the concept of the stored-program concept
• what registers are there in the Von Neumann architecture?

  
  

  Program Counter (PC),

  Memory Address Register (MAR),

  Memory Data Register (MDR),

  Accumulator
• what is the Accumulator?

  it holds the results of calculations
• What is the Program Counter (PC)?

  it holds the address of the next instruction in memory
• What is the Memory Address Register (MAR)?

  holds the address of where data is to be fetched or stored.
• What is the Memory Data Register (MDR)?

  holds the data fetched from, or to be written from memory.
• What factors can affect a CPU's overall performance?

  Clock speed,

  Cache size,

  Number of cores
• what is clock speed measured in?

  Hertz (Hz)

  Numbers of cycles per second
• what is 3.2 GHz clock speed in instructions?

  3.2 billion instructions can be fetched per second
• What is cache size?

  ~Temporary storage of data and instructions being read to and written from the RAM.

  ~Stores copies of recent data and instructions.

  ~Much quicker getting items from the cache than from the main memory.

  ~avoids getting information from memory
• what is a core?

  A core is a complete copy of a CPU
• Does the doubling of number of cores equal to double of the speed?

  no, CPU cores have to communicate with each other, this takes time, many programs are not designed to make use of multiple cores
• what is an embedded system?

  computer system with a dedicated function within a larger mechanical system
• what are the properties of a embedded system?

  low power consumption

  small size

  rugged operating

  range slow

  cost per unit
• what are some examples of embedded systems?

  Traffic lights

  Domestic appliances,

  Factory equipment,

  Engine management systems,

  Hospital equipment
• What is inside of a core?


  • Register
  • ALU
  • Accumlator
  • Control Unit