ICT 0417 – Types and Components of Computer Systems
1. Types and Components of Computer Systems
1.1 Components of a Computer System
A computer system consists of three main layers:
Hardware – physical devices such as the CPU, memory, storage, and input/output peripherals.
Software – programs and operating systems that tell the hardware what to do.
Firmware – low‑level software stored in non‑volatile memory that controls basic hardware functions.
Suggested diagram: Layered view of hardware, firmware and software in a computer system.
1.2 Types of Operating Systems (OS)
Operating systems can be classified according to how many users and tasks they can handle, and the environment in which they operate.
1.2.1 Single‑User, Single‑Task OS
Allows one user to run one program at a time. Example: early versions of MS‑DOS.
1.2.2 Single‑User, Multi‑Task OS
Supports one user running several applications simultaneously. Example: Microsoft Windows, macOS.
1.2.3 Multi‑User OS
Enables many users to access the computer resources at the same time, usually via network terminals. Example: UNIX, Linux, Windows Server.
1.2.4 Real‑Time OS (RTOS)
Designed for applications that require deterministic response times, such as industrial control or medical devices.
1.2.5 Network Operating System (NOS)
Provides services to computers connected over a network, managing resources, security and file sharing. Example: Novell NetWare, Windows Server.
1.2.6 Mobile Operating System
Optimised for handheld devices with touch interfaces and power‑saving features. Example: Android, iOS.
1.3 Advantages and Disadvantages of Different OS Types
Operating System Type
Advantages
Disadvantages
Single‑User, Single‑Task
Simple design – easy to learn.
Low hardware requirements.
Cannot run multiple programs simultaneously.
Limited productivity for modern tasks.
Single‑User, Multi‑Task
Allows multitasking – improves efficiency.
Broad software compatibility.
Rich graphical user interfaces.
Higher resource consumption (CPU, RAM).
Potential for system instability if poorly managed.
Multi‑User
Resource sharing reduces hardware costs.
Centralised administration and security.
Scalable for growing organisations.
Complex configuration and maintenance.
Requires more powerful hardware.
Potential performance bottlenecks under heavy load.
Real‑Time OS
Predictable response times – essential for critical systems.
High reliability and stability.
Specialised – limited general‑purpose software.
Often more expensive and harder to program.
Network OS
Facilitates file sharing, printers, and remote access.
Centralised security policies.
Network dependency – downtime affects many users.
Requires skilled network administration.
Mobile OS
Optimised for low power consumption.
Touch‑friendly interfaces.
Large ecosystem of apps.
Limited multitasking compared with desktop OS.
Fragmentation (different device hardware, OS versions).
Security concerns with app stores.
1.4 Summary
Choosing the appropriate operating system depends on the intended use, number of users, required reliability, and hardware resources. Understanding the strengths and weaknesses of each type helps learners make informed decisions when selecting or configuring computer systems for personal, educational, or business environments.