Exam questions

• What is meant by a computer system? (1 mark)

  It is where two or more computer devices connect together in order to share resources.
• List five computing devices that can be connected to a network. (5 marks)

  A personal computer, tablet, smart phone, printer, router.
• Describe a Local Area Network/LAN. (1 mark)

  A LAN is where computers and devices are connected together within a small geographical area - this is commonly in the same business.
• List three advantages of connecting to a LAN. (3 marks)

  Back-ups can be stored centrally, anti-virus protection can be run across the whole network, users can easily share files, software can be installed centrally, users can communicate using an internal email.
• List three disadvantages of setting up a LAN (3 marks)

  The server may stop functioning, there may be slow service, there may be viruses or malware spread through the network, expert support will be required to keep the network running, there may be security issues (users not logging off).
• Give the definition of a Wide Area Network or WAN (2 marks)


  A WAN connects two or more local area networks (LANs), in different geographical locations together.
• State the units which are normally used to measure network speed (1 mark)

  Mega bits per second / Giga bits per second
• State the factors that affect the performance of a network (2 marks)

  Interference, distance from Wi-Fi hub, band choice, channel availability.
• Define the term, 'interference' and state one possible cause for interference in this scenario (2 marks)

  Interference is the overlap of two signals on the same radio frequency. It might be caused by having too many Wi-Fi devices, forcing them to share the same channels. Non-Wi-Fi radio sources may be emitting signals on the same frequency, such as microwaves or malfunctioning electrical equipment.
• State the differences between Fibre-Optic and Ethernet cables(2 marks)

  Fibre-Optic cables use light signals in order to transfer data. Ethernet cables use electrical signals in order to transfer data. Fibre-optic cables obtain a higher bandwidth in comparison to Ethernet cables. Although, Fibre-optic cables are more expensive.
• Give the definition of contention ratio (1 mark)


  The number of users using a single connection.
• State the purpose of the network switch/hub in a client-server network (1 mark)

  It is the central point through which all connections on the network are routed.
• Outline how files are stored and shared in a peer-to-peer network (2 marks)

  Files are stored on a specific workstation, access permissions can be set by the user- for restriction to a single or a group of a files, files can be accessed from any other workstation within the network, all workstations are equal- not one computer obtains more rights in comparison to the other users.
• Explain why a peer-to-peer network may be a better choice for networking three computers in a home environment. (3 marks)


  A peer to peer network is easier to maintain. There is no need to buy an additional computer to run as the server. There is no single point of failure - if one computer goes down, only the files on that computer are lost.
• Define the term hardware (1 mark)

  Hardware is any physical part of a computer system that you can see or touch
• Give four examples of hardware (4 marks)

  Printer, Monitor, Mouse or Speaker
• Define the term software (2 marks)

  Collections of data and instructions that must be executed by the CPU
• Give three examples of software (3 marks)

  Operating System, Anti-virus Software, Word Processing Application
• Explain how data is input into a computer system and also how it reaches the CPU (4 marks)

  An input device (such as a keyboard) is used to get data into a computer system. The user presses a key on the keyboard and the data bus transits the data from the keyboard to CPU.
• Discuss the purpose of an embedded system and explain why they are found in most electronic devices (5 marks)

  A computer system built within a larger device to control its function. Due to them performing only one specific task, they are easier to design and more reliable than a general purpose computer system. Examples include: washing machine, microwave oven, cameras.
• Describe the role of the CPU (3 marks)

  The CPU fetches instructions from memory, it decodes and processes the instructions received from memory, and it executes the decoded instructions. It also manages and controls the hardware and peripherals.
• The CPU fetches instructions from memory. True or False? (1 mark)


  True
• The CPU encodes the instructions from a program. True or False? (1 mark)

  False
• The CPU executes instructions in order to process data. True or False? (1 mark)

  True
• Describe how the CPU and RAM work together to enable data to be processed (3 marks)

  Instructions and programs that are currently running are stored in RAM. The instructions are fetched by the CPU from RAM. The CPU executes these instructions in order to process data.
• Explain the purpose of cache memory (5 marks)

  Cache memory is a special type of very fast memory which stores instructions or data that are either frequently used, have recently been used or are about to be used. It enables data and instructions to be passed to and from the registers much faster as it does not need to be fetched directly from RAM.
• Identify two of the roles performed by the Control Unit (2 marks)


  It controls the way that data moves around the CPU, it controls and monitors the flow of data between the CPU and other components, such as input devices and memory, also it executes the instruction provided by the program.
• The Arithmetic Logic Unit (ALU) performs two main tasks, the arithmetic operation and the logic operation. Outline what happens during the arithmetic operation (1 mark)


  The ALU performs standard arithmetic operations such as addition, subtraction, multiplication and division.
• Explain the purpose of a register within the CPU (3 marks)

  A register is a special type of memory within the CPU which can hold a very small amount of data. They are used to temporarily hold data while a software program is running in RAM. The registers allow the CPU to access the data very quickly, even faster than using cache.
• State the role of the data bus, address bus and control bus (3 marks)

  The data bus carries data around the computer system, not just between RAM and CPU. The address bus carries information on where the data needed to go to or come from. The control bus carries signals from the control unit to control various components such as the hard disk or DVD drive.
• Explain what is meant by the term Von Neumann Architecture (2 marks)


  It is a computer system where both the data and software currently being used are stored in memory.
• Identify which part of the CPU holds the address of the next instruction on memory (1 mark)

  Program Counter
• Outline the role of the program counter (2 marks)

  It holds the address of the current instruction and updates the MAE with the address of the next instruction.
• Identify what it is that carries the program counter (1 mark)

  The software that is currently running in RAM
• Explain why the program counter doesn't always increment instruction numbers by one (2 marks)

  It may receive a branch instruction from the running software telling it to jump to a different point.
• Outline the role of the accumulator in the Von Neumann Architecture (2 marks)

  Holds temporary data while the program runs
• Explain why data is held temporarily in the accumulator, rather than simply accessing it from RAM (1 mark)

  The accumulator is much quicker to access than RAM, since it is inside the CPU itself.
• Briefly describe what happens during the fetch, decode and execute stages (3 marks)

  Fetch: Instructions and data are fetched from main memory into the CPU. Decode: The control unit checks that the instruction is valid and that it can be carried out by the CPU. Execute: The decoded instruction is carried out (1 mark)
• Suggest three things that he could do to help improve the performance of his CPU(3 marks)

  Increasing the clock speed by installing a CPU with a faster clock, installing a CPU with extra cores (going from dual core to quad core), buying a CPU with a larger cache, installing additional RAM, installing a graphics cards.
• Define what is meant by clock frequency (2 marks)

  It refers to the speed at which the clock inside the CPU ticks- the faster the clock, the more instructions that can be processed every second.