Know and understand differences between backing storage and internal memory

Types and Components of Computer Systems (ICT 0417)

1 – Hardware (internal components)

• Central Processing Unit (CPU) – executes the fetch‑decode‑execute cycle; contains arithmetic‑logic unit (ALU) and control unit.
• Motherboard (system board) – connects CPU, memory, storage and peripheral devices; holds chipset, BIOS/UEFI firmware.
• Internal Memory

  • Cache (L1, L2, L3) – ultra‑fast SRAM built into or close to the CPU.
  • RAM (Random‑Access Memory) – volatile SDRAM used as the working space for programmes.
  • ROM (Read‑Only Memory) – non‑volatile firmware (BIOS/UEFI) that starts the computer.

• Graphics Processing Unit (GPU) – renders images, video and 3‑D graphics; may have its own dedicated memory (VRAM).
• Network Interface Card (NIC) – provides wired (Ethernet) or wireless (Wi‑Fi) connectivity.
• Power Supply Unit (PSU) – converts mains AC to DC voltages required by components.
• Cooling system – fans, heat‑sinks, liquid cooling to keep components within safe temperatures.
• Input/Output peripherals – keyboard, mouse, monitor, printer, scanner, speakers, microphone, etc.

2 – Software (categories)

• System software

  • Operating System (OS) – manages hardware resources, provides a platform for applications.
  • Device drivers – translate OS commands into hardware‑specific actions.
  • Utility programmes – backup, disk‑defragmentation, antivirus, system diagnostics.
  • Language translators – compilers, interpreters, assemblers.

• Application software

  • Word processors, spreadsheets, databases, presentation software.
  • Web browsers, email clients, instant‑messaging tools.
  • Graphics and multimedia editors, games, specialised industry packages.
  • Website authoring tools (HTML editors, CMS).

3 – Internal Memory, Cache and Backing Storage

• Cache Memory – very fast SRAM situated between CPU and RAM; stores copies of frequently used instructions/data.
• Internal (Primary) Memory

  • RAM – volatile, read‑write, holds programmes and data currently being processed.
  • ROM – non‑volatile, contains firmware such as BIOS/UEFI.

• Backing (Secondary) Storage – non‑volatile devices that retain data permanently.

  • Hard‑disk drives (HDD), Solid‑state drives (SSD), Optical discs (CD‑ROM, DVD, Blu‑ray), USB flash drives, Magnetic tape, Cloud storage.

4 – Operating‑System Basics

An operating system (OS) is system software that manages hardware resources and provides a platform for application software.

• Core functions

  • Memory management – allocation of RAM and cache.
  • Process management – creating, scheduling and terminating tasks.
  • File‑system management – organising files on backing storage.
  • Device control – via drivers for printers, scanners, NICs, etc.
  • Security – user accounts, passwords, permissions, audit trails.

• User interfaces

  • Command‑Line Interface (CLI) – e.g., MS‑DOS, Unix shell.
  • Graphical User Interface (GUI) – e.g., Windows, macOS, Linux desktop environments.
  • Mobile OS – Android, iOS – optimised for touch input, power efficiency and app sandboxing.

5 – Storage Devices – Types & Characteristics

6 – Networks – Basic Concepts & Devices

• Network types

  • LAN (Local Area Network) – within a building or campus.
  • WAN (Wide Area Network) – connects multiple LANs over long distances (e.g., the Internet).

• Key devices

  • Router – forwards data between different networks; assigns IP addresses.
  • Switch – connects multiple devices within a LAN; directs traffic using MAC addresses.
  • Access point – provides wireless (Wi‑Fi) connectivity.
  • Modem – converts digital data to analogue signals for telephone or cable lines.
  • Network Interface Card (NIC) – hardware interface for wired or wireless connections.

• Common protocols – TCP/IP, HTTP/HTTPS, FTP, SMTP, Wi‑Fi (IEEE 802.11).

7 – Effects of IT on Individuals, Organisations and Society

• Individuals – improved access to information, new communication channels, digital skills requirement, privacy concerns.
• Organisations – increased productivity, automation of routine tasks, remote working, need for data security and IT governance.
• Society – global connectivity, e‑commerce, digital divide, environmental impact of e‑waste, legal and ethical issues (copyright, cyber‑crime).

8 – ICT Applications – Examples Across Sectors

• Education – e‑learning platforms, virtual classrooms, assessment software.
• Business – accounting systems, Customer Relationship Management (CRM), Enterprise Resource Planning (ERP).
• Health care – electronic patient records, tele‑medicine, diagnostic imaging.
• Entertainment – streaming services, video games, digital publishing.
• Public services – e‑government portals, online tax filing, smart‑city sensors.

9 – Systems Development Life‑Cycle (SDLC)

1. Feasibility study – assess need, cost‑benefit and risks.
2. Analysis – gather detailed requirements from users.
3. Design – plan system architecture, data structures and user interface.
4. Development – write or configure software, create databases.
5. Testing – unit, integration and user‑acceptance testing.
6. Implementation – install, train users, migrate data.
7. Maintenance – bug fixes, updates, performance monitoring.

10 – Safety & Security of Data

• Backup strategies – regular full/incremental backups, off‑site or cloud copies.
• Encryption – AES, BitLocker, file‑level encryption to protect data at rest.
• Authentication & authorisation – passwords, biometrics, two‑factor authentication, access rights.
• Physical protection – anti‑static handling, shock‑proof drives, climate‑controlled storage.
• Safe removal of removable media – “Safely Remove Hardware” to prevent corruption.
• Malware protection – antivirus, firewalls, regular updates.

11 – Audience & Communication

• Identify the intended audience (e.g., teachers, managers, general public).
• Choose appropriate tone, language and level of technical detail.
• Use visual aids (charts, diagrams, screenshots) to support textual information.
• Apply the “purpose‑audience‑message” model when planning ICT projects.

12 – File Management

• Folder hierarchy – logical grouping of related files.
• Naming conventions – avoid spaces, use dates (YYYYMMDD) and version numbers.
• File extensions – indicate format (e.g., .docx, .xlsx, .pptx, .pdf).
• Compression – ZIP or RAR to reduce size for transfer or storage.
• Search techniques – wildcard characters, advanced search filters.

13 – Working with Images

• Raster images – bitmap, resolution measured in pixels (e.g., JPEG, PNG, GIF).
• Vector images – defined by mathematical paths, scalable without loss (e.g., SVG, EPS).
• Resolution & colour depth – affect file size and print quality.
• Common editing tasks – cropping, resizing, colour correction, layering.
• Appropriate formats – JPEG for photographs, PNG for transparency, SVG for logos.

14 – Layout, Styles & Proofing in Documents

• Use built‑in heading styles for consistent formatting and automatic table of contents.
• Paragraph spacing, indents and alignment to improve readability.
• Spell‑check, grammar check and “track changes” for collaborative editing.
• Print preview – check pagination, widows/orphans and page breaks.

15 – Graphs & Charts

• Choose the correct type: bar/column (comparisons), line (trends), pie (proportions), scatter (correlation).
• Include clear titles, axis labels, units and legends.
• Use appropriate scales – avoid distortion of data.
• Interpretation – be able to describe what the graph shows and any significant patterns.

16 – Document Production (Word Processing)

• Creating and saving documents in standard formats (DOCX, ODT, PDF).
• Inserting tables, images, headers/footers and page numbers.
• Using mail merge for personalised letters or labels.
• Applying templates and styles for consistent branding.

17 – Databases

• Key concepts – tables, fields (columns), records (rows), primary key, foreign key.
• Data manipulation – INSERT, UPDATE, DELETE, SELECT (queries).
• Forms for data entry; reports for data presentation.
• Relational DBMS examples – Microsoft Access, MySQL, PostgreSQL.
• Normalization – reducing redundancy, improving integrity.

18 – Presentations

• Slide design – limited text, high‑contrast colours, consistent layout.
• Use of multimedia – audio, video, animation (sparingly).
• Presenter notes and timing tools.
• Export options – PDF, video, PowerPoint Show (PPSX).

19 – Spreadsheets

• Cell referencing – relative, absolute (\$A\$1) and mixed.
• Common functions – SUM, AVERAGE, IF, VLOOKUP/HLOOKUP, COUNTIF.
• Data visualisation – charts, conditional formatting.
• Data analysis tools – sorting, filtering, pivot tables.
• Protection – sheet and workbook passwords.

20 – Website Authoring

• Markup language – HTML5 structure (, , ).
• Styling – CSS for layout, colours, fonts.
• Web editors – WYSIWYG (e.g., Adobe Dreamweaver) and code‑centric (e.g., Visual Studio Code).
• Publishing – uploading files via FTP or a content‑management system (CMS).
• Accessibility – alt text for images, semantic headings, colour contrast.

21 – Review: Key Differences – Internal Memory vs. Backing Storage

Key AO Links (Cambridge IGCSE ICT 0417)

• AO1 – Knowledge & Understanding: All sections provide the factual basis required (hardware components, memory hierarchy, OS functions, SDLC, safety & security, etc.).
• AO2 – Application of Knowledge: Practical examples (using word processors, spreadsheets, databases, web authoring tools, creating backups, configuring network settings) demonstrate how learners can apply concepts in real‑world tasks.
• AO3 – Analysis & Evaluation: Sections on effects of IT, safety & security, and the SDLC encourage learners to evaluate benefits, risks and suitability of different technologies and solutions.

Summary

Internal memory (cache and RAM) gives the CPU the ultra‑fast, temporary workspace needed for processing, while backing storage provides large, permanent space for the operating system, applications, user data and backups. Understanding their differences in volatility, speed, capacity, cost and role is essential for managing information efficiently, protecting data, and selecting appropriate technologies in a wide range of ICT contexts.