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Exam practice

Understanding Computer Science

  • The CPU - Eduqas

    Most general purpose computers are based on von Neumann architecture. This includes using the fetch-decode-execute cycle to process program instructions. Computer performance depends on cache size, clock speed and the number of cores.

  • Primary storage - Eduqas

    Primary storage is a key component of a computer system that enables it to function. Primary storage includes random access memory (RAM), read only memory (ROM), cache and flash memory. Each of these have different uses within the computer.

  • Secondary storage and embedded systems - Eduqas

    Computers need to be able to store programs and data indefinitely when the power is switched off. Magnetic, optical and solid state devices are different types of secondary storage used to store the data and programs. Each type has different functions in terms of suitability, durability, portability and speed.

  • Networks - Eduqas

    Devices can be networked using different hardware, such as routers, hubs, switches, gateways and bridges. They can cover local areas (LANs) or wider areas (WANs). Networks are constructed using different topologies, including ring, bus, star and mesh. All of these differences have advantages and disadvantages to users.

  • Internet and cybersecurity - Eduqas

    Networks operate on the principles of communication and sharing. Unfortunately, these principles mean that network traffic and data can be more easily accessed by people who have no authority to do so. Different vulnerabilities need to be identified and measures put in place to protect systems from them.

  • Data representation - Eduqas

    Binary data can represent numbers, graphics, sound and characters. It is then organised and manipulated differently. Data can also be stored in arrays, records or external files and go through validation or verification checks to ensure accuracy.

  • Storage and data organisation - Eduqas

    Arrays form the basis for how data is stored within a program. They must be declared with meaningful identifier names and appropriate data types that match the data. Without the correct data structures and data types, programs will not work.

  • Operating systems - Eduqas

    Operating systems control a computer鈥檚 resources and provide an interface for users to be able to communicate with these resources. Utility software helps to maintain the system.

  • Principles of programming - Eduqas

    Programming languages can be categorised as high-level and low-level. They each have very different characteristics and are used for different purposes. Machine code and assembly languages are very different to the languages most programmers use.

  • Algorithms - Eduqas

    Algorithms are step-by-step plans for solving problems. They are a starting point when writing a program. Algorithms can be designed using pseudo-code and flowcharts.

  • Sorting, searching and validation - Eduqas

    Sorting and searching are two of the most frequently needed tasks in program design. Common algorithms have evolved to take account of this need, such as linear search, binary search, bubble sort and merge sort.

  • Software development - Eduqas

    Translators like compilers, interpreters and assemblers are needed to translate programs written in high-level languages into the machine code that a computer understands. There are different stages in the compilation process. Tools exist to help programmers develop error-free code.

  • Impacts of digital technology on wider society - Eduqas

    The use of computers has brought about environmental, ethical and legal issues and concerns. These increasingly affect people's daily lives.

Systems analysis

  • Problem solving - Eduqas

    Computers can be used to help solve complex problems using computational thinking. This means that before a problem can be tackled, it must first have been through decomposition and abstraction. This will result in a modular programmed solution with subroutines and clear interfaces.

  • Security and authentication - Eduqas

    Data needs to be validated so that it does not stop software from functioning. Validation should be programmed into software to prevent this happening. There are standard checks which can be used to do this. Authentication and verification aim to restrict access to computer systems from unauthorised users.

  • Programming constructs - Eduqas

    Programs are created using common building blocks, known as programming constructs. These programming constructs form the basis for all programs and are also used in algorithms.

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