1.4 Wired and Wireless Networks

This section of the OCR GCSE Computer Science revision resources focuses on network types and key networking concepts. It provides students with essential knowledge about different network configurations and their characteristics.

The page begins by defining a network as a group of connected devices that can share data and resources. It emphasizes that networks can be either wired (using Ethernet) or wireless (using Wi-Fi).

The guide then introduces two main types of networks:

1. Local Area Network (LAN):

   • Covers a small geographical area, such as an office
   • Uses its own infrastructure

2. Wide Area Network (WAN):

   • Covers a larger geographical area
   • Often connects multiple LANs
   • May use infrastructure owned by other organizations

Definition: A Local Area Network (LAN) is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building.

The page also introduces several key networking terms:

• Bandwidth: The maximum amount of data that can be transmitted over a network connection in a given time.
• Server: A powerful computer that provides services or resources to other computers (clients) on the network.
• Client: A device or software that accesses services or resources provided by a server.

Vocabulary: Bandwidth refers to the maximum rate of data transfer across a given path in a network.

While the page is incomplete, it lays the foundation for understanding network types and key networking concepts. Students preparing for their OCR GCSE Computer Science exam should be familiar with these terms and concepts, as they are likely to appear in exam questions related to computer networks.

Highlight: Understanding the differences between LANs and WANs, as well as key networking terminology, is crucial for success in the GCSE Computer Science exam.

The information provided on this page serves as a starting point for more detailed discussions on network topologies, protocols, and network security, which are likely covered in subsequent sections of the GCSE Computer Science OCR Revision Guide PDF.

1.1 Systems Architecture

The systems architecture section of this GCSE Computer Science OCR Revision Guide PDF focuses on the fundamental components and processes of computer systems. It provides a comprehensive overview of the Central Processing Unit (CPU) and its key functions.

The page begins by explaining that computer systems process data through input, processing, and output. It then introduces the concept of embedded systems, which are specialized computers built into other devices for specific tasks.

The guide elaborates on three crucial factors affecting CPU performance:

1. Clock speed: Determines how many instructions a processor can execute per second.
2. Number of cores: Affects the CPU's ability to multitask and process instructions simultaneously.
3. Cache size: Influences the CPU's access speed to frequently used data.

A significant portion of the page is dedicated to explaining the fetch-decode-execute cycle, which is fundamental to understanding how a CPU operates. This cycle is presented both visually and in text format for better comprehension.

Definition: The fetch-decode-execute cycle is the basic operational process of a computer's CPU, consisting of three main steps: fetching an instruction from memory, decoding it, and executing it.

The page also includes a detailed diagram of the CPU, labeling and explaining each component:

• Control Unit (CU)
• Program Counter
• Arithmetic Logic Unit (ALU)
• Accumulator
• Cache
• Memory Address Register (MAR)
• Memory Data Register (MDR)

Highlight: Understanding the roles of these CPU components is crucial for students preparing for their GCSE Computer Science OCR exam.

The page concludes with a set of exam questions, encouraging students to apply their knowledge and practice answering questions related to CPU performance, embedded systems, and the fetch-decode-execute cycle.