A computer system consists of hardware and software components that work together to perform various operations. Hardware refers to the physical parts of a computer that can be touched and seen. Major hardware components include: processors, memory devices, keyboard, monitors etc. Whereas, Software consists of set of instructions and programs that instruct the hardware resources to perform certain tasks and functionalities properly.

Hardware

Hardware in computers refers to the physical components that make up a computer system. These are the tangible parts you can see and touch. Hardware works together with software (programs and instructions) to perform computing tasks.

The major components of a computer system are:

• Central Processing Unit (CPU)
• Input Unit
• Output Unit
• Motherboard
• Memory Unit

Central Processing Unit (CPU)

A CPU (Central Processing Unit) is the primary component of a computer that performs most of the processing inside a computer system. It is often referred to as the “brain” of the computer because it executes instructions from programs, performs calculations, manages data flow, and controls other hardware components.

The Key functions of a CPU is to Fetch, Decode, Execute and Store.

When input is given to the CPU form the input device, initially it fetches instructions from memory, then decodes or interprets the instructions to understand what task to be performed. It then executes or performs the required task. . Finally, it then stores the result or displays it on an output device. which directs operations; and Memory Registers, which store temporary data.

Inside CPU, there are three major components:

• Control Unit (CU) – The Control Unit (CU) is a crucial component of the CPU (Central Processing Unit) responsible for directing the operation of the processor. It acts as the “manager” of the CPU, coordinating how data moves between different parts of the CPU and ensuring instructions are executed in the correct sequence.
• Arithmetic Logic Unit (ALU) – The ALU (Arithmetic Logic Unit) is a fundamental component of the CPU (Central Processing Unit) responsible for performing all mathematical calculations (addition, subtraction, multiplication and division) and logical operations. It is the “calculator” inside the processor that handles computations required by software and system processes.
• Registers – A register is a small, ultra-fast storage location inside the CPU (Central Processing Unit) used to hold data, instructions, or memory addresses temporarily during processing. Unlike RAM (which is slower and larger), registers are built directly into the CPU, allowing instant access for computations.

Input Unit

The Input Unit is a critical component of a computer system responsible for accepting data and commands from external devices and converting them into a form that the computer can process. It acts as the bridge between the user (or external environment) and the computer’s processing unit (CPU).

Major Functions of an Input Unit

1. Accepts Data
   • Receives input from devices like keyboards, mice, scanners, microphones, etc.
2. Converts Input
   • Translates human-readable data (e.g., keystrokes, voice) into binary signals (0s and 1s) for the CPU.
3. Sends Data to Memory/CPU
   • Transfers the converted data to RAM or directly to the CPU for processing.
4. Handles Device Communication
   • Manages protocols for devices (e.g., USB, Bluetooth, HDMI).

The examples of Input Unit are: keyboard, mouse, scanner, web cam, microphone, bard code reader etc.

Output Unit

The Output Unit is a component of a computer system that displays or transmits processed data from the CPU to the user or another device. It converts machine-readable results (binary data) into a human-readable or machine-usable form, such as text, images, sound, or control signals.

The major functions of an output unit are:

1. Receives Processed Data
   • Takes results from the CPU or memory after computation.
2. Converts Binary Data
   • Translates 0s and 1s into visual, audio, or physical output.
3. Displays or Transmits Results
   • Shows output on screens, prints on paper, plays sound, or sends signals to other machines.
4. Handles Device Communication
   • Manages connections to monitors, printers, speakers, etc.

The examples of an output device are: display unit, monitors, speakers, printers, etc.

Motherboard

The motherboard (also called the mainboard or system board) is the primary circuit board in a computer that connects and allows communication between all critical hardware components. It acts as the central hub, ensuring the CPU, RAM, storage, and other devices work together.
The Key Functions of a Motherboard are:

Allows adding graphics cards (PCIe), Wi-Fi cards, and more.

• Connects All Components of computer like RAM, GPU, storage (SSD/HDD), and other hardware.
• Provides Power & Data Pathways
• Manages Communication– The chipset (Northbridge/Southbridge in older systems) controls data flow.
• Expansion Slots Allows adding graphics cards (PCIe), Wi-Fi cards, and more.

Memory Unit

Computer memory refers to the electronic components that store data and instructions temporarily or permanently for processing by the Central Processing Unit (CPU). It’s essential for any computer operation. There are two main types of memory :

1. Primary Memory (Main Memory / RAM – Random Access Memory)

• Purpose: Stores data and instructions currently being used by the CPU. It enables fast access for active tasks.
• Characteristics:
  • Volatile: Loses all data when power is turned off.
  • Fast: Much quicker than secondary storage (nanosecond access times).
  • Directly Accessible: The CPU reads/writes directly to RAM.
• Types: DDR4, DDR5, SRAM (used in CPU cache).
• Analogy: Like a “workspace” or “desk” – holds tools and papers you’re actively using.

2. Secondary Memory (Storage)

• Purpose: Stores data permanently even when powered off (e.g., OS, apps, documents).
• Characteristics:
  • Non-Volatile: Retains data without power.
  • Slower: Access times in milliseconds or microseconds.
  • High Capacity: Significantly larger than RAM (terabytes vs. gigabytes).
• Examples:
  • HDDs (Hard Disk Drives): Magnetic storage (affordable, high capacity).
  • SSDs (Solid State Drives): Flash memory (faster, more durable, no moving parts).
  • USB Drives, SD Cards: Portable flash storage.

Software

Software refers to a set of instructions, programs, and data that tell a computer how to perform specific tasks. Unlike hardware (physical components like CPU, RAM, and hard drives), software is intangible and runs on hardware to enable functionality.

Types of Software

Software’s are broadly classified into two categories.

• System Software
• Application Software

System Software

System software is a type of computer program designed to manage and control hardware resources, providing a platform for running application software. It acts as an intermediary between users, applications, and computer hardware.

Types of System Software

1. Operating System (OS)

The core software that runs a computer.

• Examples:
  • Windows (11, 10)
  • macOS (Sonoma, Ventura)
  • Linux (Ubuntu, Fedora)
  • Android, iOS (for mobile)

2. Device Drivers

Enable communication between hardware and the OS.

• Examples:
  • Printer drivers
  • GPU drivers (NVIDIA, AMD)
  • USB/Bluetooth drivers

3. Firmware

Permanent software embedded in hardware.

• Examples:
  • BIOS/UEFI (motherboard firmware)
  • Router firmware
  • Smartwatch OS

4. Utility Software

Tools for system maintenance and optimization.

• Examples:
  • Antivirus (Windows Defender, Norton)
  • Disk cleanup (CCleaner)
  • Backup tools (Acronis)

Application Software

Application software (or “apps”) refers to programs designed to help users perform specific tasks, such as creating documents, browsing the web, editing photos, or playing games. Unlike system software (which manages hardware and runs the OS), application software serves end-user needs.