Paper 1

• The Central Processing Unit (CPU) is the part of a computer that carries out program instructions and is responsible for data processing.
• The Arithmetic Logic Unit (ALU) is a component of the CPU that carries out math and logic operations needed to execute instructions.
• The Control Unit coordinates the fetch-execute cycle and performs vital decode and instruction cache functions.
• Instruction Cache is a type of memory that holds frequently accessed instructions, data, and addresses.
• The Memory Address Register (MAR) is an address register that holds the address of where data is being fetched from or written to in memory.
• The Program Counter is an address register that holds the address of the next instruction to be fetched from memory.
• The Accumulator holds the results of ALU calculations.
• Von Neumann Architecture is a structure built on these components and this structure carries out a fetch-execute cycle.
• The Fetch-Execute cycle consists of three stages: Fetch, Decode, and Execute.
• During Fetch, an instruction is fetched from memory using the address given in the Program Counter.
• During Decode, the Control Unit decodes the instruction, interpreting it and figuring out what to do next.
• During Execute, the instruction is carried out, usually done by the ALU, and additional data may be fetched.
• The clock speed of a CPU is the rate at which the Fetch-Execute cycle is carried out.
• Multiple cores in a CPU allow each core to do its own cycle at the same time, meaning instructions can be executed at the same time.
• Cache size is another factor that affects performance, as a bigger cache can store more regularly used items, reducing reliance on slower RAM and speeding up operations.
• Embedded systems are computers held inside other devices such as household appliances and cars, usually with one purpose only.
• Solid state storage includes solid state drives (SSDs) which are a big chunk of circuitry with loads of logic gates, and are durable because nothing is moving inside.
• An example of optical storage is a DVD which uses light and different reflections of light to represent binary one and binary zero.
• When storing lots of things in binary, different binary units are used: bit, nibble, byte, kilobyte, megabyte, gigabyte, terabyte, petabyte, exabyte, zettabyte, and yottabyte.
• Secondary storage is slower than RAM and is used as virtual memory when the system runs out of RAM.
• Magnetic storage includes hard disk drives (HDDs) which work by having two levels of magnetic polarity on the disk surface, representing binary one and binary zero.
• RAM stands for random access memory which can be changed.
• ROM is read-only memory which contains the program that runs as soon as the system boots up.
• There are three main types of secondary storage: magnetic storage, optical storage, and solid state storage.
• Ram is an extension of secondary storage used as virtual memory when the system runs out of RAM.
• Conversion between binary, hexadecimal, and decimal can be done using place value tables.
• ROM's main job is to load the operating system into RAM once the OS is in RAM, other programs can be loaded into RAM.
• Secondary storage is where the vast majority of programs and data are stored, it's non-volatile and kept for long term.
• Encryption and data compression software are examples of utility software.
• Certain software is open source, meaning the source code is publicly available and can be copied and pasted into another program.
• System software includes utility software, which is aimed at keeping the general running of the computer smooth and efficient.
• Defragmentation software, which only works on magnetic hard drives, aims to speed up these often older hard drives by reorganizing the disk to move programs so they're as close together as possible.
• The Data Protection Act is about personal data and the responsibility of organizations to look after it, with individuals having certain rights.
• The Computer Misuse Act is about hacking and malware, making both illegal and punishable by prison sentences.
• The user interface is what the user sees on the screen, with two types being Graphical User Interfaces (GUIs) and Command Line Interfaces (CLIs).
• Peripherals are external devices like headsets and printers, with drivers being installed by the operating system.
• The Copyright, Designs and Patents Act is about intellectual property, protecting ideas and things people have created.
• User management relates to the creation of multiple accounts, with partitioning and the password system also managed by the operating system.
• Programs need to be loaded from secondary storage into primary storage before they are executed, a process controlled by the operating system.
• Multitasking is a feature of most operating systems where multiple programs can be executed simultaneously.