GCSE COMPUTER SCIENCE PAPER 2

paper 2 computer concepts

Computer

A programmable device that takes in data, processes it into useful information, and displays an output.

Hardware

Any physical, tangible component of a computer

Internal Hardware

Components inside the computer system, such as the CPU, and RAM.

External Hardware / Peripheral Devices

Hardware used to communicate with the system through input and output

Software

Programs that run on a computer and enable hardware to function

System Software

Manages the computer system’s resources and provides a platform for application software to run

Utility Software

Type of system software

Helps maintain, manage, and protect a computer system

Application Software

Software designed to perform tasks for the end user

Functions of an Operating System

• User Interface (UI) – Allows the user to interact with the computer (e.g. GUI or command line).

• Memory Management – Allocates and manages RAM for programs.

• Processor Management – Decides which processes run and when (multitasking).

• Peripheral Management – Controls communication with devices such as printers, keyboards and mice.

• File Management – Organises, stores, retrieves and deletes files.

• User Management – Creates user accounts and manages access permissions.

• Security Management – Protects the system using passwords, encryption and access controls.

• Multitasking – Allows multiple applications to run at the same time.

• Interrupt Handling – Responds to signals from hardware and software that need immediate attention.

Types of Utility Software

• Anti-virus software – Detects and removes malware.

• Encryption software – Scrambles data so only authorised users can read it.

• Backup software – Creates copies of files for recovery if data is lost.

• Compression software – Reduces file size to save storage space and speed up transfers.

• Defragmentation software – Reorganises fragmented files on HDDs to improve performance.

• File management software – Organises, copies, moves, renames and deletes files and folders.

Main Memory

Component of the computer that holds data and programs that are currently in use

Volatile Memory

Temporary memory that requires continuous power to retain data, meaning all stored contents are lost when the power is turned off (e.g. RAM).

Non Volatile Memory

Permanent memory that does not require continuous power to retain data, meaning stored contents are preserved even when the power is turned off (e.g. ROM).

Virtual Memory

A section of secondary storage used as an extension of RAM when main memory is full.

Cache

High-speed volatile memory built into or located close to the CPU that stores frequently accessed instructions and data to speed up processing.

ROM

Non-volatile memory that stores essential startup instructions (firmware) needed to boot the computer, which can be read from but not easily modified or overwritten.

RAM

Temporary memory that stores data and instructions currently being used by the CPU. RAM is volatile, meaning its contents are lost when the computer is turned off.

Register

Registers are very small, high-speed storage locations inside the CPU that temporarily hold data, instructions, and memory addresses currently being processed.

Types of Registers

Program Counter(PC)

Current Instructions Register (CIR)

Memory Address Register (MAR)

Memory Data Register (MDR)

Accumulator (Acc)

Secondary Storage

Non-volatile storage that permanently stores data and programs when the computer is turned off.

Solid State Storage

Storage that uses flash memory chips to store data electronically, with no moving parts (e.g. SSDs and USB flash drives).

Advantages of Solid State Storage

Faster, more durable, less likely to be damaged, uses less power, smaller/lighter, and quieter than hard disk drives (HDDs).

Disadvantages of Solid State Storage

More expensive, usually lower capacity for the same price, and memory cells wear out after a limited number of writes.

Magnetic Storage

Magnetic storage stores data by magnetising and demagnetising regions of a magnetic surface, such as a hard disk drive (HDD).

Advantages of Magnetic Storage

High capacity, low cost per GB, suitable for large files and backups, and can store lots of data cheaply.

Disadvantages of Magnetic

Slower, less durable, uses more power, noisier, and more prone to physical damage than solid-state storage.

Cloud Storage

Storage where data is stored on remote servers and accessed over the internet.

Embedded Systems

A computer system inside another device that carries out a specific function.

Control Unit (CU)

The part of the CPU that controls and coordinates the execution of instructions and the flow of data.

Arithmetic Logic Unit (ALU)

The part of the CPU that carries out arithmetic calculations (e.g. addition) and logical operations (e.g. comparisons).

Clock

A component that generates timing signals to synchronise the CPU's operations.

Buses

Communication pathways that transfer data, instructions and addresses between computer components.

Types of Buses

• Data bus – carries data.

• Address bus – carries memory addresses.

• Control bus – carries control signals and commands.

How does clock speed affect CPU performance?

A higher clock speed means more clock cycles per second, allowing the CPU to process more instructions and generally perform faster.

How does the cache affect CPU performance?

A larger cache allows the CPU to access frequently used data faster, reducing the need to access RAM and increasing performance.

How does the number of cores affect CPU performance?

A CPU with more cores can process more tasks simultaneously, increasing performance and improving multitasking.