Know and understand system software provides the services that the computer requires to operate

ICT 0417 – Types and Components of Computer Systems

Learning Objective

Know and understand that system software provides the services a computer requires to operate.

1. Overview of Computer Systems

1.1 What is a Computer System?

• A computer system = hardware (physical components) + software (instructions that tell the hardware what to do).
• Software is divided into:
  • System software – manages hardware and provides a platform for other software.
  • Application software – performs user‑oriented tasks (e.g., word processing, web browsing).
• Data can be:
  • Analogue – continuous signals (e.g., sound wave voltage).
  • Digital – binary values (0/1). Most modern computers work with digital data; analogue signals are converted by ADCs and DACs.

1.2 Internal vs. External Memory

• Primary (internal) memory – directly accessed by the CPU.
  • RAM (Random‑Access Memory) – volatile, holds data/programs while they are running.
  • ROM (Read‑Only Memory) – non‑volatile, stores firmware such as BIOS/UEFI.
• Secondary (external) storage – retains data when power is off; accessed via I/O controllers.
  • Hard‑disk drives (HDD), solid‑state drives (SSD), USB flash drives, optical discs, cloud storage.

1.3 Main Hardware Components

1.4 Types of Computer Systems (Cambridge Syllabus 1‑5)

1.5 Emerging Technologies (brief note for syllabus 1.5)

Artificial Intelligence (AI) and Extended Reality (XR – AR/VR) are increasingly integrated into all categories of computers, influencing hardware design (e.g., specialised GPUs) and requiring new system‑software services such as machine‑learning libraries and low‑latency graphics drivers.

2. System Software – The Service Provider

2.1 Core Services Provided by System Software

• Resource Management – allocates CPU time, RAM, and storage to running programmes.
• File Management – creates, reads, writes, deletes files; maintains directory structures.
• Device Management – controls peripherals via device drivers.
• Security Services – authenticates users, enforces access controls, protects against malware.
• User Interface – CLI, GUI, dialogue‑based or gesture‑based interaction.

2.2 Types of System Software

1. Operating System (OS) – primary system software that manages hardware and provides a platform for applications.
   • Examples: Windows, macOS, Linux, Android, iOS.
   • Interface varieties:
     • CLI – text‑based commands (e.g., MS‑DOS, Linux terminal).
     • GUI – windows, icons, menus (e.g., Windows 11, macOS).
     • Dialogue‑based – prompts and forms (common in mobile‑OS settings).
     • Gesture‑based – touch and motion gestures (Android, iPadOS).
2. Utility Programs – perform system‑maintenance tasks such as disk defragmentation, backup, antivirus scanning, file compression.
3. Device Drivers – small specialised programmes that translate OS commands into hardware‑specific signals (e.g., printer driver, graphics driver).
4. Firmware (BIOS/UEFI) – low‑level software stored in non‑volatile ROM.
   • Runs Power‑On Self Test (POST) to check hardware integrity.
   • Initialises basic hardware (keyboard, storage controllers).
   • Loads the OS bootloader from storage into RAM.
   • Provides a configuration interface for system settings (boot order, security).

2.3 How System Software Enables Operation

1. Power‑on → firmware (BIOS/UEFI) performs POST, checks hardware, and loads the OS bootloader.
2. The OS kernel initialises core services and loads required device drivers, establishing communication with all attached hardware.
3. System calls become available to application programmes, allowing them to request services (file access, screen output, network communication).
4. The OS scheduler allocates CPU time slices; the memory manager handles RAM allocation; the I/O manager coordinates data transfer to/from devices.
5. Security mechanisms (login, permissions, firewalls) protect data and ensure only authorised actions are performed.

3. Input and Output Devices

3.1 Input Devices (with characteristics, advantages & disadvantages)

3.2 Direct Data‑Entry Devices

• Magnetic‑stripe reader (e.g., credit‑card terminals)
• RFID reader (contactless cards, inventory tags)
• Barcode scanner (retail, logistics)
• Optical Character Recognition (OCR) scanner – converts printed text to editable digital text.
• Voice recognition software – converts spoken words to text/commands.

3.3 Output Devices (with characteristics, advantages & disadvantages)

4. Storage Devices and Media

4.1 Primary vs. Secondary Storage

• Primary (internal) memory – RAM and ROM; accessed directly by the CPU, volatile (RAM) or non‑volatile (ROM).
• Secondary (external) storage – HDD, SSD, optical discs, USB flash drives, cloud servers; used for long‑term data retention.

4.2 Storage Media (with pros/cons)

5. Networks and Their Effects

• Network Types – LAN, WAN, Internet, Intranet.
• Key Hardware – NIC, router, switch, wireless access point, modem.
• Connectivity Options – Ethernet (copper/fibre), Wi‑Fi, Bluetooth, cellular (3G/4G/5G).
• Effects of Using IT
  • Positive: faster communication, instant access to information, collaborative work, e‑commerce.
  • Negative: digital divide, data‑privacy issues, cyber‑security threats.

6. Health, Safety and Environmental Considerations

• Physical health – avoid repetitive strain injury (RSI) by taking regular breaks; use ergonomic keyboards/mice.
• Visual health – follow the 20‑20‑20 rule (every 20 min look at something 20 ft away for 20 sec) and adjust screen brightness/contrast.
• Electrical safety – use surge protectors, ensure proper grounding, never handle components while the system is powered.
• Environmental impact – recycle e‑waste, choose energy‑efficient devices, consider the carbon footprint of cloud services.

7. ICT Applications – Why System Software Matters

• Communication – email, instant messaging, video‑conferencing (Zoom, Teams).
• Data Management – spreadsheets, databases, cloud storage (Google Drive, OneDrive).
• Modelling & Simulation – CAD, scientific modelling tools.
• Banking & Finance – online banking portals, ATM software.
• Education – virtual learning environments, e‑books, interactive simulations.
• Creative Media – photo/video editing, music production, game development.

8. Systems Development Life‑Cycle (SDLC)

1. Analysis – identify user requirements and system constraints.
2. Design – create system architecture; choose hardware, OS and utility software.
3. Implementation / Coding – install system software, develop or install application software.
4. Testing – verify that all components work together; check security, performance and usability.
5. Documentation – produce user manuals, technical guides, and maintenance records.
6. Evaluation & Maintenance – monitor system performance, apply updates/patches, plan for upgrades.

9. Summary Checklist

• System software is the layer that makes hardware usable and provides essential services.
• Core services: resource management, file management, device control, security, and user interface.
• Major types: operating system (CLI/GUI/dialogue‑based/gesture‑based), utility programs, device drivers, firmware (BIOS/UEFI).
• Computer categories range from supercomputers to smartphones; each has distinct advantages and disadvantages.
• Input devices, direct‑data‑entry devices, output devices and storage media all have specific characteristics, pros and cons that must be understood.
• Networks enable communication but introduce health, safety, security and environmental considerations.
• The SDLC ensures that hardware, system software and applications are selected, installed and maintained effectively.