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IB DP Computer Science Study Notes

6.1.1 Identification of System Resources

In High-Level IB Computer Science, understanding the architecture and capabilities of computer systems is pivotal. This set of notes delves into the various resources within a computer system, elucidating their functions and their roles in overall system performance.

Primary Memory

Primary memory, or RAM (Random Access Memory), is a volatile memory used for storing data and machine code currently being used. It’s essential due to:

  • Temporary Storage: It temporarily stores operating system instructions, user data, and application software information needed immediately by the CPU.
  • Speed and Volatility: RAM is fast, providing data to the CPU at high speeds but loses its data when power is off, distinguishing it from secondary storage.
  • Size and System Performance: The size of RAM in a computer (commonly ranging from 4GB to 32GB and beyond) directly impacts how many applications can run simultaneously and how swiftly they operate. Insufficient RAM can lead to paging and swapping, slowing down the system.

Secondary Storage

Secondary storage is non-volatile, holding data permanently until deliberately erased. It encompasses various types:

  • Hard Disk Drives (HDDs): Magnetic storage devices, known for their large storage capacity and lower cost per GB, but slower compared to SSDs.
  • Solid-State Drives (SSDs): Faster than HDDs, as they use flash memory, leading to quicker boot times, application launch times, and file-transfer speeds.
  • Optical Drives: Such as CD, DVD, and Blu-ray discs, used for distributing software, music, videos, and for archival purposes.

Processor Speed

The processor, or CPU, is the brain of the computer. Its speed, typically in GHz, is a critical determinant of system performance:

  • Multicore Processors: Modern CPUs contain multiple cores, enabling them to process several instructions simultaneously, greatly enhancing performance.
  • Hyper-Threading: Some processors can execute multiple threads per core, further boosting multitasking and computational efficiency.
  • Heat Generation: Higher clock speeds can lead to increased heat production, necessitating effective cooling solutions.


Bandwidth in computer systems primarily refers to the rate at which data is transmitted over a network or computing components. It’s significant for:

  • Data Transfer Rate: Measured in bits per second (bps), it indicates how fast data moves across the network or computer components.
  • Bottlenecks: Limited bandwidth in networks or buses (connections between different parts of a computer) can cause performance bottlenecks.

Screen Resolution

Screen resolution determines the clarity and detail of visuals displayed:

  • Pixels: The more pixels on the screen, the higher the resolution, and hence, the sharper the image.
  • Aspect Ratio: Common aspect ratios like 16:9 or 4:3 influence the display's shape and size.
  • High-Definition (HD): Resolutions like 1080p (1920x1080 pixels) or 4K (3840x2160 pixels) provide finer details for gaming, graphic design, and video viewing.

Disk Storage

Storage capacity is a fundamental aspect of a computer's disk storage:

  • Unit of Measurement: Capacity is often measured in gigabytes (GB) or terabytes (TB), with modern systems featuring terabyte-scale capacities.
  • Storage Media Types: Besides HDDs and SSDs, newer types like NVMe (Non-Volatile Memory Express) drives offer higher speeds over traditional interfaces like SATA (Serial Advanced Technology Attachment).

Sound Processor

The sound processor, or audio card, is integral to a computer’s audio output quality:

  • Digital-to-Analog Conversion (DAC): It converts digital audio data to an analog signal for headphones or speakers.
  • Sound Quality: Higher-quality sound cards can reduce noise and distortion, providing clearer audio, which is crucial in professional audio workstations.

Graphics Processor

Graphics processors or GPUs are specialised hardware for rendering images and video:

  • Dedicated vs Integrated GPUs: Dedicated GPUs (separate hardware) typically offer better performance than integrated GPUs (built into the CPU).
  • Uses: Beyond gaming and graphic design, GPUs are increasingly used in areas like machine learning, video editing, and simulations.


Cache is a smaller, faster type of volatile memory located in or close to the CPU:

  • Levels: There are usually multiple levels of cache (L1, L2, and L3), with L1 being the fastest and smallest.
  • Function: Cache stores copies of frequently accessed data to speed up data retrieval, effectively reducing the average time to access memory.

Network Connectivity

The capability of a computer system to connect to or communicate with other networks:

  • Wired and Wireless Connections: Ethernet offers stable and fast speeds, whereas Wi-Fi provides portability and convenience.
  • Internet Protocols (IP): IPv4 and IPv6 are the protocols through which devices are identified and communicate over a network.

Understanding these system resources in depth provides IB Computer Science students with the foundation to analyse, evaluate, and optimise computer systems. Comprehending how each component contributes to the system’s overall performance, and recognising potential upgrade paths, prepares students for real-world applications and problem-solving in computing. This knowledge is not only academically beneficial but also vital in making informed decisions in a technologically evolving world.


Network connectivity is considered a system resource because it determines a computer's ability to communicate with other systems and access remote resources and services, like the Internet or networked storage. The speed (bandwidth) and quality (latency, jitter) of the network connection can significantly affect a computer's functionality. For instance, a high-speed, low-latency network is essential for online gaming, video conferencing, and streaming high-definition videos, where delays or interruptions can degrade the user experience. Similarly, in environments like cloud computing or remote desktop applications, network speed impacts how quickly data can be transferred between the computer and the server, influencing overall system responsiveness and performance.

Cache memory in a CPU is a small, extremely fast memory designed to speed up the process of accessing data from the primary memory (RAM). The primary function of cache memory is to store instructions and data that are frequently accessed by the CPU, thus reducing the time to retrieve data from the main memory. Cache memory is faster than RAM but is also more expensive, which is why it's smaller in size. It's typically divided into three levels (L1, L2, and L3), with L1 being the smallest and fastest. In contrast, RAM is larger and slower but serves as the main memory space for running applications and storing the data that is currently in use. The effective use of cache memory can significantly enhance the overall speed and efficiency of a computer system by minimizing the delay in data retrieval and processing.

Screen resolution, the number of pixels displayed on the screen, directly affects a computer's graphic processing. Higher resolutions, such as 4K, require the Graphics Processing Unit (GPU) to calculate and render significantly more pixels than standard resolutions like 1080p. This increased load can impact performance, particularly in graphics-intensive tasks such as gaming or 3D modelling. Higher resolutions demand more computing power and memory bandwidth from the GPU, often resulting in a lower frame rate or the need for more advanced, powerful graphic hardware. Therefore, while a high resolution provides a sharper and more detailed image, it also places greater demands on the system’s graphics resources.

Increasing the RAM in a computer system can significantly improve the performance of software applications, particularly those that are memory-intensive. More RAM allows a computer to store more operational data, like application files and processes, in a quickly accessible space. This capability is crucial for multitasking and running large applications like video editors, games, or virtual machines. When a system runs out of RAM, it starts using the much slower hard disk or SSD for data, leading to performance lags or stuttering. Therefore, more RAM can enable smoother operation, faster application responses, and better handling of complex tasks without frequent recourse to disk-based virtual memory.

The type and speed of a hard drive have a significant impact on a computer system's overall performance. Hard Disk Drives (HDDs) use mechanical parts and magnetic storage, which makes them generally slower in read/write speeds compared to Solid-State Drives (SSDs). SSDs use flash memory and have no moving parts, leading to faster data access times, lower latency, and quicker boot times. The speed of these drives is measured in terms of their data transfer rate: SSDs can drastically improve system responsiveness, application loading times, and file transfer rates. For tasks involving frequent disk access like video editing or gaming, SSDs offer a noticeable performance enhancement over HDDs. Moreover, SSDs are more durable and have a lower failure rate due to their lack of mechanical parts.

Practice Questions

Explain how the processor speed and the amount of primary memory can affect the performance of a computer system.

The processor speed, measured in gigahertz (GHz), is crucial as it determines how many instructions per second the CPU can execute. A higher speed means more instructions can be processed, leading to faster execution of tasks and smoother operation of complex software. On the other hand, the amount of primary memory, or RAM, is equally important. RAM is a high-speed component that temporarily stores all the data a system needs in the short term and what it’s currently working on. More RAM allows a system to work with more information at the same time and reduces reliance on slower secondary storage. Therefore, insufficient RAM can lead to a bottleneck in performance, regardless of the processor speed, as the system would need to constantly swap data with the slower secondary storage.

Describe the role of a graphics processor (GPU) and how it differs in function from the main processor (CPU) in a computer system.

A Graphics Processing Unit (GPU) is specialised hardware designed primarily for rendering images and videos, significantly offloading these tasks from the Central Processing Unit (CPU). While the CPU can handle a variety of tasks and is essential for the overall functioning of the computer, the GPU is particularly adept at handling the complex mathematical and geometric calculations required for graphics rendering. This division of labour allows the CPU to focus on other tasks, thereby improving the computer's overall performance. GPUs contain hundreds of cores for processing large blocks of visual data simultaneously, making them incredibly efficient for tasks such as 3D gaming, video rendering, and running graphic-intensive applications, which would be highly inefficient if handled by the CPU alone.

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Written by: Alfie
Cambridge University - BA Maths

A Cambridge alumnus, Alfie is a qualified teacher, and specialises creating educational materials for Computer Science for high school students.

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