Leaving Certificate Computer Science Notes: Computer Systems

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Key Lessons: Computer Systems – Leaving Certificate Computer Science

• What is a Computer System? A computer system is a combination of hardware, software, and peripherals working together to perform tasks and process data. It includes essential components like the central processing unit (CPU), memory, storage devices, and input/output devices.

• Hardware and Software: Hardware refers to the physical components of a computer system, while software includes the programs and applications that instruct the hardware on how to operate. Both are critical for the functioning of any computer system.

• CPU and Memory: The central processing unit (CPU) acts as the brain of the computer, performing calculations and executing instructions. Memory, such as RAM, stores data temporarily while the CPU processes it, allowing fast access to information.

• Operating System (OS): The operating system is the software that manages hardware and software resources. It allows users to interact with the computer and runs essential tasks like file management, security, and process scheduling.

• Peripherals and Storage: Peripherals like keyboards, mice, and monitors enable interaction with the computer, while storage devices (e.g., hard drives and SSDs) are used to save and retrieve data. Understanding how these elements work together is crucial for understanding modern computer systems.

Important Takeaways: Computer Systems – Leaving Certificate Computer Science

• Central Processing Unit (CPU): The CPU is the brain of the computer, handling instructions and executing tasks. It consists of components like the Arithmetic & Logic Unit (ALU) and registers, which perform calculations and store data temporarily.

• Memory Types: RAM (volatile memory) temporarily stores data while the CPU works on it, whereas ROM (non-volatile memory) stores critical instructions. Both play essential roles in how a computer functions.

• Von Neumann Architecture: This architecture defines a computer system where the CPU, memory, and input/output devices are central components. The Von Neumann bottleneck refers to performance limitations due to the system's design, where data and instructions share the same memory.

• Harvard Architecture: Unlike Von Neumann, Harvard architecture uses separate memory for instructions and data, improving performance by allowing simultaneous fetching. However, it can be more expensive and complex to produce.

• Fetch-Decode-Execute Cycle: This cycle is the process through which the CPU processes instructions—fetching, decoding, and executing one at a time. This is central to understanding how computers carry out tasks.

Keywords: Computer Systems, Leaving Certificate, Computer Science, System Architecture, Hardware Components, Operating Systems, System Design, Computer Architecture, Input/Output Devices, System Integration