GCSE Computer Science Unit 1 Test Prep

State the purpose of the CPU.

• The CPU carries out processing on the computer, it does this by fetching and executing instructions

• The CPU carries out processing on the computer, it does this by fixting and executing instructions

• The GPU carries out processing on the computer, it does this by fetching and executing instructions

State two types of operation carried out by the ALU.

• Arithmetic operations

• Logic (comparison) operations

• Litix operations

• Rendering Opurx transfixing's

Describe the steps involved in the Fetch-Decode-Execute cycle

• The CPU gets the instruction from memory.

  The address of the next instruction is stored in the Program Counter .
  The PC is stored in the MAR.

  The Program counter is incremented.

  The instruction is stored in the MDR.

  The instruction is decoded and executed.

• The CPU gets the instruction from memory.

  The address of the next instruction is stored in the Program Counter .
  The PC is stored in the MDR.

  The Program counter is incremented.

  The instruction is stored in the MAR.

  The instruction is decoded and executed.

• The CPU gets the instruction from memory.

  The address of the next instruction is stored in the MCR .
  The PC is stored in the MAR.

  The Program counter is incremented.

  The instruction is stored in the MDR.

  The instruction is decoded and executed.

• The CPU gets the instruction from memory.

  The address of the next instruction is stored in the Program Counter .
  The PC is stored in the MAR.

  The Program counter is decremented.

  The instruction is stored in the MDR.

  The instruction is decoded and executed.

With reference to memory, describe the characteristics of von Neumann architecture

• In von Neumann architecture, both the program and data are stored together in same memory.

  This uses the stored program concept

• In von Neumann architecture, both the program and data are stored separately in different memory locations. .

  This uses the stored program concept

Explain what the MAR is used for.

• The MAR holds the address of the instruction/data currently being used

• The MAR holds the calculation of the result of processing

• The MAR holds the only the of the instruction currently being used

Explain how the following can affect the performance of a CPU - Clock Speed

• The lower the clock speed, the more instructions can be executed per second as every operation starts on a clock pulse . This improves the performance.

• The higher the clock speed, the more instructions can be executed per second as every operation starts on a clock pulse . The lower the clock pulse the better the performance.

• The higher the clock speed, the more instructions can be executed per second as every operation starts on a clock pulse . This improves the performance.

Explain how the following can affect the performance of a CPU: number of cores

• The less cores there are, the more processors there are processing data at the same time.

  Less cores will improve performance in some circumstances, but the computer system may not always be able to take advantage of more than one core

• The more cores there are, the more processors there are processing data at the same time.

  More cores will improve performance in some circumstances, but the computer system may not always be able to take advantage of more than one core

Define what is meant by an embedded system

• A computer system which is built into another device and can be changed without replacing the hardware in which it is embedded. A computer system that has a multi-purpose function e.g. A washing machine.

• A computer system which is built into another device and cannot be changed without replacing the hardware in which it is embedded. A computer system that has a dedicated function e.g. A washing machine.

• A computer system which is built into general purpose

• A robot that likes to sleep in bed

State two differences between RAM and ROM

• RAM is volatile whereas ROM is non-volatile

• RAM is read/write whereas ROM is read only (1).

• RAM is fast and ROM slow

• One likes to disco

What is Virtual Memory?

• extra memory that is used when the RAM is full. A part of the Secondary Storage device acts like RAM, providing extra temporary memory.

• Memory that wanted to be a VR Game

• extra memory that is used when the ROM is full. A part of the Secondary Storage device acts like ROM, providing extra temporary memory.

• extra memory that is used when the Cache is full. A part of the Secondary Storage device acts like Cache providing extra temporary memory.