Yr10 February Mock - QFocus

Page 1: CPU Performance and Components

Cache Size and CPU Performance

• The cache size significantly impacts CPU performance. A larger cache allows data to be transferred faster to the CPU, enhancing its efficiency.

• Data retrieval from the cache is quicker than from RAM, reducing latency in processing tasks.

Identifying Computer Components

• Key components of a computer can be defined as follows:

  • MAR (Memory Address Register): Stores a single memory address.

  • MDR (Memory Data Register): Stores frequently used instructions and data.

  • Cache: Holds data that is frequently accessed for faster processing.

  • Program Counter: Keeps track of the instructions being executed.

  • RAM (Random Access Memory): Contains all currently running data and instructions.

Registers in CPU

• An example of a register not listed in the earlier table is the accumulator. This register is used to store the results of arithmetic and logic operations temporarily.

Audio File Conversion Process

• When converting music (e.g., an audio file of guitar playing) into a digital format, the height of sound waves gets sampled. This measurement occurs at regular intervals, turning the analog signal into a digital one represented by binary code.

Page 2: Memory, Storage, and Compression

Character Set

• A character set refers to all the different characters that a computer can represent.

ASCII Representation

• ASCII (American Standard Code for Information Interchange) can represent 256 different characters. This encoding system allows computers and devices to communicate text in a standard format.

Estimating File Size

• To estimate the file size of a text file with 2000 characters:

  • Calculate bits: 2000 characters * 8 bits/character = 16000 bits

  • Convert to bytes: 16000 bits / 8 = 2000 bytes

  • Convert to kilobytes: 2000 bytes / 1000 = 2 kilobytes.

Compression Methods

• For reducing the file size of images and videos, compression methods that significantly reduce size while maintaining quality include:

  • Decreasing the overall file size, which also results in faster uploads to, and downloads from, servers.

Functions of a Router

• Key tasks performed by a router include:

  • Receiving, forwarding, transmitting packets of data across networks.

  • Maintaining routing tables that determine the best paths for data.

  • Identifying and selecting the most efficient paths to various destinations.

  • Assigning unique IP addresses to devices on a network.

  • Converting packets from one network protocol to another.

Page 3: Protocols and Addressing

Layered Protocols

• Protocols utilize layers for various reasons:

  • Each layer operates independently, allowing for individual changes without affecting others.

  • Layers can be tailored for specific tasks, facilitating specialized development.

  • Standards can be established for each layer, ensuring compatibility.

IP Address Examples

• A valid IPv4 address follows the format of four groups of denary numbers (0-255) separated by dots.

  • Example: 123.16.46.72

• A valid IPv6 address is composed of eight groups of hex numbers separated by colons, which can include a double colon that replaces consecutive zero groups.

  • Example: 0252:5985:89ab:cdde:a57f:89ad:efcd:00fe

Format of a MAC Address

• A MAC (Media Access Control) address is typically formatted in hexadecimal, consisting of:

  • 6 groups of two-digit hexadecimal numbers (totaling 12 hex numbers).

  • A length of 48 bits.

  • The first half identifies the manufacturer, while the second half signifies the device's unique serial number.

Page 4: Importance of Encryption

Need for Encryption

• Libraries transmitting data without encryption face potential risks. Reasons for implementing encryption include:

  • Protecting the integrity and confidentiality of intercepted data, making it unrecognizable if compromised.

  • Ensuring that only authorized personnel access sensitive or personal information is crucial for compliance with legislation like the Data Protection Act (DPA).

Revision Status Tracker

• The topics under review include Systems Architecture, focusing on CPU and memory/storage concepts, as well as Computer Networks, which covers hardware and addressing protocols.