Outline the architecture of the central processing unit (CPU) and the functions of the arithmetic logic unit (ALU) and the control unit (CU) and the registers within the CPU.
The Central Processing Unit (CPU) is the main component responsible for calculations and controlling in a computer. It consists of the Arithmetic and Logic Unit (ALU) and registers, which include the Program Counter (PC), Memory Address Register (MAR), Memory Data Register (MDR), Current Instruction Register (CIR), Index Register (IR), and Status Register (SR). The Von Neumann architecture is a basic structure that includes these registers. The fetch-decode-execute cycle is the flow of data through the processor, where the program counter value is copied to the MAR, data is retrieved from the memory location, the content is placed in the MDR, then decoded and executed. Finally, a check for interrupts is made, the program counter is iterated, and the loop starts again. It is important to follow a logical order when completing the fetch-decode-execute cycle.
Describe primary memory.
Primary storage, or main memory, is directly accessible by the CPU and temporarily stores data and instructions that the CPU is currently working on. It includes Random Access Memory (RAM) and read-only memory (ROM), where ROM is non-volatile and stores data that cannot be changed or overwritten, while RAM is volatile and provides the CPU with quick access to frequently used data. RAM and ROM serve different purposes, with ROM providing permanent storage of essential system information, and RAM providing temporary storage of frequently accessed data and instructions. There are different types of RAM and ROM, and the amount of RAM in a computer can significantly affect its performance.
Explain the use of cache memory
Cache memory is a small, high-speed memory that stores frequently used data for quick access. It is used to speed up data processing by temporarily storing data so that it can be quickly retrieved and used again, rather than being fetched from slower storage devices. Cache memory is used in different contexts such as processor cache, disk cache, and web browser cache. By reducing the amount of time it takes to access and process data, cache memory can significantly improve the performance of a computer system. The use of both an address bus and a data bus in cache memory allows for efficient and fast data retrieval, further improving the overall performance of the system.
Explain the machine instruction cycle
The Central Processing Unit (CPU) goes through to execute a machine instruction. It consists of three stages: fetch, decode, and execute. During the fetch stage, the CPU retrieves the next machine instruction from memory, using the program counter to determine the memory address. The instruction is then copied into the instruction register, ready for the next stage. In the decode stage, the CPU determines what operation needs to be performed based on the instruction that was fetched. It decodes the instruction by breaking it down into its constituent parts and identifying the operands and the operator. In the execute stage, the CPU performs the operation specified by the instruction on the data in the registers. This may involve arithmetic or logical operations, or transferring data between registers or memory. Once the execution is complete, the machine instruction cycle repeats, with the CPU fetching the next instruction from memory and repeating the process. This cycle continues until the program is complete or an error occurs.
SECONDARY MEMORY | FLIP CARDS
Identify the need for persistent storage
Secondary storage, also known as external or auxiliary storage, is a type of computer storage used for long-term data storage. It provides slower access speeds but larger storage capacity compared to primary storage. Examples of secondary storage devices include hard disk drives, solid-state drives, optical discs, USB flash drives, memory cards, magnetic tapes, external hard drives, network-attached storage devices, and cloud storage services. Persistent storage is a type of storage needed to store data in a non-volatile device during and after the running of a program. It is necessary to preserve any data that needs to be saved for future use, including system backups and disaster recovery. Overall, secondary and persistent storage are essential components of modern computing, providing reliable and cost-effective ways to store large amounts of data for long periods of time.
OPERATING SYSTEMS AND APPLICATION SYSTEMS | FLIP CARDS
Describe the main functions of an operating system
An operating system is software that manages the hardware and software resources of a computer. It acts as an intermediary between the computer hardware and the applications that run on the computer. It manages files, handles interrupts, provides an interface, manages peripherals and drivers, manages memory, multitasking, provides a platform for running applications, provides system security, and manages user accounts. Popular operating systems include Windows, macOS, Linux, and Android. The operating system provides the necessary support and services to run applications, manage memory, handle input/output operations, and perform other tasks, and it is the first software that is loaded when the computer starts up.
Outline the use of a range of application software
Application software is designed to perform specific tasks or functions for the user and is used directly by the user, unlike system software which manages and operates the computer system. Examples of application software include word processors, spreadsheets, database management systems, email clients, web browsers, CAD software, and graphics software. These tools are essential for users to accomplish specific tasks and achieve their goals.
Identify common features of applications
Applications often have common features such as a Graphical User Interface (GUI), toolbars, menus, dialogue boxes, and a help system. The GUI allows users to interact with the application through graphical elements such as windows, icons, buttons, and menus. Toolbars provide quick access to frequently used commands, while menus provide a hierarchical list of commands and functions. Dialogue boxes enable the user to interact with the application by entering data or responding to prompts. A help system provides assistance in the form of documentation, tutorials, or online help. It is crucial for applications to be intuitive to the user, and a well-designed GUI with consistent features can help achieve this, improving productivity and user experience.
BINARY REPRESENTATION | FLIP CARDS
Define the terms: bit, byte, binary, denary/decimal, hexadecimal.
Outline the way in which data is represented in the computer
Data in computers is represented using binary digits, or bits, which can have a value of either 0 or 1. Different types of data, such as strings, integers, characters, and colours, are represented using different combinations of bits. Strings, which are sequences of characters, are typically represented using ASCII (American Standard Code for Information Interchange) or Unicode encoding, where each character is assigned a unique binary code. Unicode is used because ASCII is limited to representing only 128 characters, which is not sufficient to represent all the characters of different languages and scripts used across the world. Unicode is a character encoding standard that can represent almost all the characters used in any language, including symbols, alphabets, and characters from various scripts. Unicode uses a variable-length encoding scheme, which means it can represent a much larger number of characters than ASCII.
Colours are represented using a combination of red, green, and blue (RGB) values, each of which can have a value from 0 to 255. The total number of possible colours that can be represented using RGB values is 256^3, or over 16 million colours. Colours can also be represented using hexadecimal notation, which uses a combination of numbers and letters to represent the RGB values.
The amount of space taken up by data depends on the type of data and how it is represented. For example, a single ASCII character takes up 8 bits, or 1 byte, of space, while a single Unicode character takes up 16 bits, or 2 bytes. The amount of space taken up by integers and colours depends on the number of bits used to represent them