paper 1

• What is the purpose of the CPU?

  Processes data and instructions using FDE cycle and controls the rest of the computer system
• Describe the steps of the Fetch-Decode-Execute Cycle

  1. The program counter displays the address in RAM of the next instruction to be processed. The value is copied into the MAR

  2. The program counter is incremented by 1 which prepares the CPU for the next instruction to be fetched

  3. The instruction in RAM is transferred to the MDR

  4. The instruction in the MDR is copied into the CIR

  5. The instruction in the CIR is decoded and executed. Any result of an execution is stored in the accumulator

  6. The process is repeated
• What is Von Neumann Architecture?

  Stores both instructions and data in memory, enables it to multitask and run several applications at once, and a key feature is data input and output
• What is the function of the Control unit?

  Directs the flow of data and information into the CPU. It also controls the other parts of the CPU
• What are registers?

  Temporary storage spaces for data and instructions inside the CPU
• What is the function of the Arithmetic logic unit?

  Performs mathematical calculations and logical operations
• What is the function of Cache?

  Used to temporarily store data that is frequently accessed
• What is the function of the program counter?

  Stores the address of the next instruction to be fetched from memory
• What is the function of the Memory Address Register?

  Stores the address of the instruction that is to be fetched
• What is the function of the Memory Data Register?

  Holds the instruction that is fetched from memory or is to be sent to memory
• What is the function of the Current Instruction Register?

  Stores the instruction that is currently being decoded or executed.
• What is the function of the accumulator?

  Temporarily stores the result of operations carried out in the ALU before it is transferred to memory
• What is the function of a CPU clock?

  It is used to coordinate all of the computer's components by sending out a regular electric pulse.
• How does clock speed affect CPU performance?

  The higher the frequency (Hz), the more instructions can be performed at any given moment in time.
• What does overclocking cause?

  Overheating and damage
• What is cache memory?

  A small amount of high-speed RAM built directly within the processor, used to temporarily hold data and instructions that the processor is likely to reuse.
• How does cache memory impact CPU performance?

  Data can be transferred to and from cache memory more quickly than from RAM. The bigger its cache, the less time a processor has to wait for instructions to be fetched.
• What is the disadvantage of cache?

  Expensive
• What is a core in a CPU?

  A processing unit within a CPU capable of fetching, decoding, and executing instructions.
• How does the number of cores impact CPU performance?

  The more cores a CPU has, the greater the number of instructions it can process simultaneously.
• What are the disadvantages of multiple cores?


  Some software not written for use of multiple cores
• What is an embedded system?

  A computer system with a dedicated function built within a larger mechanical device
• What are 3 examples of embedded systems?

  Washing machines, TVs, microwaves
• What is primary storage?

  Low capacity, internal storage that can be directly accessed by the CPU, very quick, typically smaller in storage size
• What is RAM (Random Access Memory)?

  Volatile memory that stores all programs that are currently running. RAM also stores parts of the operating system to be accessed by the CPU, can be read and written to
• What is ROM (Read Only Memory)?

  Non-volatile storage that cannot be changed, stores the BIOS for when the computer is switched on, can be read but not written to
• What is virtual memory?

  Part of the hard drive used as an extension to RAM
• What are the advantages of virtual memory?

  Uses cheap secondary storage on the hard drive and prevents error messages since the files and programs will still open
• What are the disadvantages of virtual memory?

  Accessing virtual memory is very slow
• What is secondary storage?


  Non-volatile storage used to save and store data that can be accessed repeatedly, slower to access than primary storage as it is further away from the CPU
• How does magnetic storage work?


  A read/write head moves nano metres above the disk platter and uses the magnetic field of the platter to read or edit data
• What are 3 magnetic storage examples?


  Hard disk drives (most common within desktop computers), magnetic tape (high storage capacity but data has to be accessed in order so it is generally only used by companies to back up or archive large amounts of data), floppy disks (replaced by solid state devices as they are much faster and have a higher capacity)
• What are the advantages of magnetic storage?

  Large capacity, cheaper cost than solid state, faster access speed than optical storage
• What are the disadvantages of magnetic storage?


  Not durable and not very portable when powered on because moving it can damage the device, slow access speed
• How does optical storage work?


  Uses a laser to project beams of light onto a spinning disc, allowing it to read data from a CD, DVD or Blu-ray
• Is optical internal or external storage?


  Traditionally internal but external disc drives can be bought for devices like laptops
• What is the purpose of optical storage?


  Used for a variety of purposes such as storing music, movies, games etc
• What are the advantages of optical storage?

  Discs are thin and very portable, cheap to buy in bulk
• What are the disadvantages of optical storage?


  Low capacity, not durable because discs are very fragile and can break or scratch easily, slowest access speed
• What is solid state storage replacing and why?


  SSDs are replacing magnetic HDDs in modern computers and video game consoles because they are generally quieter, faster and use less power