What is machine code?

Machine code is instructions in binary that a processor can execute directly. Each instruction is a pattern of 0s and 1s.

Why will machine code written for one processor not run on a different type of processor?

Each processor, or family of processors, has its own instruction set. A binary pattern that means one instruction on one processor may mean something else on another.

What is assembly language?

Assembly language is a low-level language that uses short mnemonics such as ADD and SUB. Each mnemonic stands for one machine code instruction.

AQA GCSE Computer Science 8525

Algorithms

Topic overview Algorithms, decomposition and abstraction Pseudo-code, flowcharts and trace tables Efficiency of algorithms Linear search and binary search Bubble sort and merge sort

Programming

Topic overview Data types Variables, constants and assignment Sequence, selection and iteration Arithmetic, relational and Boolean operators Arrays and records Input, output, string handling and random numbers Subroutines and structured programming Validation, authentication and testing

Data Representation

Topic overview Number bases and why hexadecimal is used Converting between binary, decimal and hexadecimal Units of information: bits, bytes and prefixes Binary addition and binary shifts Character encoding: ASCII and Unicode Pixels, bitmaps and colour depth Bitmap image file size calculations Digital sound: sampling rate and sample resolution Data compression: Huffman coding and run-length encoding

Computer Systems

Topic overview Hardware, software and the operating system Logic gates, truth tables and Boolean expressions Programming languages and translators The CPU and the fetch-execute cycle Types of memory and embedded systems Secondary storage and cloud storage

Computer Networks

Topic overview Network types and topologies Wired and wireless networks Network protocols The TCP/IP model and its layers Network security methods

Cyber Security

Topic overview Cyber security, common threats and penetration testing Social engineering: blagging, phishing and shouldering Malware: viruses, trojans and spyware Methods to detect and prevent cyber security threats

Relational Databases and SQL

Topic overview Relational databases and keys SQL SELECT queries SQL INSERT, UPDATE and DELETE

Ethical, Legal and Environmental Impacts of Digital Technology

Topic overview Ethical issues in digital technology Legal issues, privacy and surveillance Environmental impacts of digital technology

Computer Systems

Programming languages and translators

3 things to know
Paper 2

Overview

High-level and low-level languages, machine code and assembly language, the advantages of each, and how assemblers, compilers and interpreters translate code and when to use each.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

What is a high-level language?

Key term

What is a low-level language?

Key term

Why are most programs written in high-level languages?

Questions from this subtopic

Each one with the model answer underneath.

1
What is a high-level language?
Model answer
A high-level language uses English-like keywords and is not tied to one type of processor. Python and C# are examples.
2
What is a low-level language?
Model answer
A low-level language is close to the instructions a processor actually carries out. Machine code and assembly language are both low-level languages.
3
Why are most programs written in high-level languages?
Model answer
High-level code is quicker to write, read and debug. The same program can run on different types of processor once it has been translated.
4
What is machine code?
Model answer
Machine code is instructions in binary that a processor can execute directly. Each instruction is a pattern of 0s and 1s.
5
Why will machine code written for one processor not run on a different type of processor?
Model answer
Each processor, or family of processors, has its own instruction set. A binary pattern that means one instruction on one processor may mean something else on another.
6
What is assembly language?
Model answer
Assembly language is a low-level language that uses short mnemonics such as ADD and SUB. Each mnemonic stands for one machine code instruction.

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Algorithms

Programming

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Computer Systems

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