Section 1- Components of a Computer System

• What is a computer?

  A machine that processes data
• What is the purpose of a computer?

  To take data, process it and output it
• What is hardware? Examples?

  Physical components that make up a computer system.

  CPU, motherboard, monitor, printer.
• What is software? Examples?

  The programs or applications that a computer system runs.

  Operating system, word processor.
• What is a general-purpose computer?

  A computer designed to perform a variety of tasks.
• What is an embedded system?

  A computer system designed to perform specific tasks within a larger system.
• What are some examples of embedded systems?

  Smartwatches, washing machines, microwaves, navigation systems.
• What does CPU stand for?

  Central Processing Unit
• What is the CPU?

  The brain of the computer that processes all the data and instructions that make the system work.
• What are the 3 main parts of the CPU?

  Control Unit, Arithmetic Logic Unit, and Cache.
• What is the control unit?

  A component of the CPU that manages and coordinates the execution of instructions- manages the fetch-decode-execute cycle
• What does ALU stand for?

  Arithmetic Logic Unit
• What is the ALU?

  Completes all the calculations- arithmetic and logic
• What is the cache?

  Very fast piece of memory which stores frequently used data so the CPU can access it quicker
• What are the properties of cache?

  Faster access, small capacity, expensive.
• What are the properties of L1 cache?

  Quickest out of the levels but has smallest capacity
• What are the properties of L3 cache?

  Slower than L1 cache but has the highest capacity
• What is the Von Neumann architecture?

  The description of the fetch-decode-execute cycle process
• What does PC stand for?

  Program Counter
• What does the PC hold?

  The memory address of the instruction for each cycle
• What does the MAR stand for?

  Memory Address Register
• What does the MAR hold?

  Holds any memory address about to be used by the CPU
• What does MDR stand for?

  Memory Data Register
• What does the memory address register hold?

  Holds the actual data or instruction
• What is the accumalator?

  A register
• What does the accumalator hold?

  Immediate results of calculations in the ALU
• What happens in the fetch stage of the fetch-decode-execute cycle?

  -copy memory address from PC to MAR

  -copy instruction stored in MAR address to the MDR

  -increment the program counter to the point of the next instruction for the next cycle
• What happens in the decode part of the fetch-decode-execute cycle?

  -the instruction in the MDR is decoded by the CPU

  -CU may prepare for the next step
• What happens in the execute part of the fetch-decode-execute cycle?

  -instruction is performed

  -could be writing data to memory, loading data or a calculation
• What are the properties of RAM?

  Volatile and high speed
• What does RAM stand for?

  Random Access Memory
• What is RAM used as?

  Main memory
• What is volatile memory?

  Temporary storage that loses its data when power is turned off.
• What is non-volatile memory?

  Memory that retains data even when power is turned off.
• What does main memory hold?

  Data, files and programs while they're being used
• What is virtual memory?

  Secondary storage used as extra RAM
• What is virtual memory for?

  For when the RAM is full and the computer needs somewhere else to put application data- too many applications open at once
• How can virtual memory affect the computer?

  Performance is slower when switching between applications
• What does ROM stand for?

  Read-Only Memory
• What are the properties of ROM?

  Non-volatile, only be read