COMP 01: Computer Systems – Theory

This is assessed by a written paper, which has a mixture of short and long answer questions. 15% AO1, 22% AO2 and 3% AO3. No calculators allowed.
Written paper, 1 hour 30 mins, 80 marks, 40% of qualification.

You need to revise below listed topics for your up coming exam. Use available resources in your Google Classroom, Dynamic learning, the internet and the given links on this website to revise each topics.

1.1 Systems Architecture

  • Purpose of CPU and Components
  • Von Neumann Architecture & Fetch Execute Cycle
    • MAR (Memory Address Register)
    • MDR (Memory Data Register)
    • Program Counter
    • Accumulator
  • Common Characteristics & Performance
    • ALU (Arithmetic Logic Unit)
    • CU (Control Unit)
    • Cache
  • the function of the CPU as fetch and execute instructions stored in memory
  • how common characteristics of CPUs affect their performance:
    • clock speed
    • cache size
    • number of cores
  • Embedded Systems
    • purpose of embedded systems
    • examples of embedded systsems.

1.2 Memory

  • Purpose of ROM & RAM and difference between them
  • Flash Memory and need for Virtual Memory

1.3 Storage

  • Need for secondary storage & common types
    • optical
    • magnetic
    • solid state
  • suitable storage devices and storage media for a given application, and the advantages and disadvantages of these, using characteristics:
    • capacity
    • speed
    • portability
    • durability
    • reliability
    • cost


  • bit, nibble, byte, kilobyte, megabyte, gigabyte, terabyte, petabyte
  • how data needs to be converted into a binary format to be processed by a computer.


  • the use of binary codes to represent characters
  • the term ‘character-set’
  • the relationship between the number of bits per character in a character set and the number of characters which can be represented (for example ASCII, extended ASCII and Unicode).


  • how an image is represented as a series of pixels represented in binary
  • metadata included in the file
  • the effect of colour depth and resolution on the size of an image file.


  • how sound can be sampled and stored in digital form
  • how sampling intervals and other factors affect the size of a sound file and the quality of its playback:
    • sample size
    • bit rate
    • sampling frequency


  • need for compression
  • types of compression:
    • lossy
    • lossless

1.4 Wired & Wireless Networks

  • Types of networks and factors that affect performance
    • PAN (Personal Area Network)
    • LAN (Local Area Network)
    • WAN (Wide Area Network)
  • Hardware needed to connect to a LAN and virtual networks
    • Wireless access points
    • Routers/switches
    • NIC (Network Interface Controller/Card)
    • Transmission media
  • Client-server and peer-to-peer networks
  • The internet as a worldwide collection of computer networks:
    • DNS (Domain Name Server)
    • Hosting
    • The cloud
  • The concept of virtual networks

1.5 Network Topologies, Protocols & Layers

  • Wifi
    • frequency and channels
    • encryption
  • Ethernet
  • Star and mesh topologies
  • the uses of IP addressing, MAC addressing, and protocols including:
    • TCP/IP (Transmission Control Protocol/Internet Protocol)
    • HTTP (Hyper Text Transfer Protocol)
    • HTTPS (Hyper Text Transfer Protocol Secure)
    • FTP (File Transfer Protocol)
    • POP (Post Office Protocol)
    • IMAP (Internet Message Access Protocol)
    • SMTP (Simple Mail Transfer Protocol)
  • the concept of layers
  • Packet switching

1.6 Systems Software

  • The purpose and functionality of systems software
  • Operating systems
    • user interface
    • memory management/ multitasking
    • peripheral management and drivers
    • user management
    • file management
  • Utility system software
    • encryption software
    • defragmentation
    • data compression
    • the role and methods of backup:
      • full backup
      • incremental backup

1.7 Systems Security – YEAR 11 unit

  • Forms of attack
  • Threats posed to networks
    • malware
    • phishing
    • people as the ‘weak point’ in secure systems (social engineering)
    • brute force attacks
    • denial of service attacks
    • data interception and theft
    • the concept of SQL injection
    • poor network policy
  • Identifying and preventing vulnerabilities
    • penetration testing
    • network forensics
    • network policies
    • anti-malware software
    • firewalls
    • user access levels
    • passwords
    • encryption

1.8 Issues – YEAR 11 unit

  • How to investigate and discuss Computer Science technologies while considering:
    • ethical issues
    • legal issues
    • cultural issues
    • environmental issues
    • privacy issues
  • how key stakeholders are affected by technologies
  • environmental impact of Computer Science
  • cultural implications of Computer Science
  • open source vs proprietary software
  • legislation relevant to Computer Science:
    • The Data Protection Act 1998
    • Computer Misuse Act 1990
    • Copyright Designs and Patents Act 1988
    • Creative Commons Licensing
    • Freedom of Information Act 2000