Digitalization of Data II


A computer system consists of three main parts otherwise called components. They are :

  1. Hardware
  2. Software
  3. Peopleware

Sure! Let’s expand on the components of a computer system.

1. Hardware:
Hardware refers to the physical components of a computer system that can be seen and touched. It includes devices such as the central processing unit (CPU), motherboard, memory (RAM), storage devices (hard drives, solid-state drives), input devices (keyboard, mouse, scanner), output devices (monitor, printer), and various peripheral devices (speakers, webcam, etc.). These components work together to process and store data, and they provide the necessary interface for users to interact with the system.

2. Software:
Software refers to the non-physical, intangible parts of a computer system. It includes programs, applications, and operating systems that are stored digitally and provide instructions for the hardware to perform specific tasks. The software can be categorized into two main types:

– System software: This includes the operating system (such as Windows, macOS, Linux) that manages the computer’s resources and provides a platform for running other software. It also includes device drivers that enable communication between hardware components and the operating system.

– Application software: These are programs designed to perform specific tasks or provide certain functionalities. Examples include word processors, web browsers, photo editing software, video players, and games. Application software allows users to accomplish various tasks on a computer system.

3. Peopleware:
Peopleware refers to the human elements involved in the use, operation, and management of a computer system. It includes the users, system administrators, developers, and other personnel who interact with the system. Peopleware focuses on human-computer interaction, user experience, training, support, and overall management of the system. Effective peopleware ensures that the hardware and software components are utilized optimally, and users can efficiently achieve their goals using the computer system.

The three components – hardware, software, and peopleware – work together to form a complete computer system. Hardware provides the physical infrastructure, software provides the instructions and functionality, and peopleware ensures efficient use and management of the system. Without any of these components, a computer system would not be functional or usable.


Hardware is the physical parts of the computer system that you can see and touch. They are the components that make up the visible computer. It consists of devices for input, processing, storage, output, and communications.

The basic parts of computer hardware can be divided into:

1. System Unit:
The system unit is the central part of a computer that houses essential components responsible for processing and storing data. It typically consists of the following components:

– Central Processing Unit (CPU): The CPU, often referred to as the “brain” of the computer, carries out instructions and performs calculations. It interprets and executes instructions from the computer’s memory, performs arithmetic and logical operations, and coordinates the activities of other hardware components.

– Motherboard: The motherboard is a circuit board that serves as a platform for connecting various components of the computer system. It houses the CPU, memory, expansion slots, connectors for peripherals, and interfaces for storage devices.

– Memory (RAM): Random Access Memory (RAM) is a type of volatile memory that provides temporary storage for data and instructions that the CPU needs to access quickly. RAM allows for faster data retrieval compared to permanent storage devices.

– Storage Devices: These devices are responsible for long-term storage of data and programs. Common examples include hard disk drives (HDDs) and solid-state drives (SSDs), which store data magnetically and electronically, respectively.

2. Peripherals:
Peripherals are devices that are connected to the computer system to enhance its functionality and provide input, output, or auxiliary capabilities. They include:

– Input Devices: Input devices allow users to provide data and commands to the computer system. Examples include keyboards, mice, touchscreens, scanners, and microphones.

– Output Devices: Output devices display or present information processed by the computer system. Common examples include monitors, printers, speakers, and projectors.

– Storage Devices: In addition to the storage devices mentioned earlier, peripherals such as external hard drives, USB flash drives, and memory cards provide additional storage capacity for backing up and transferring data.

– Communication Devices: These devices enable the computer system to connect and communicate with other systems or networks. Examples include network interface cards (NICs) for wired or wireless connectivity, modems, and routers.

– Other Peripherals: There is a wide range of other peripherals available, including webcams, graphics tablets, game controllers, and external sound cards, which provide specialized functionalities and cater to specific user needs.

These basic hardware components, including the system unit and peripherals, collectively form the visible and tangible parts of a computer system. They work together to facilitate input, processing, storage, output, and communication functions, enabling users to interact with and utilize the computer system effectively.


The CPU is the brain of the computer system and it can be subdivided into:

  1. Control Unit
  2. Arithmetic and Logic Unit
  3. Memory Unit


The Control Unit is a crucial component of a computer system responsible for coordinating and managing the execution of instructions. It works closely with the Central Processing Unit (CPU) and other hardware components to ensure the smooth operation of the system. Let’s expand on the role and functions of the Control Unit:

1. Instruction Fetching:
The Control Unit is responsible for retrieving instructions from the main memory (RAM) or cache memory. It determines the address of the next instruction to be fetched and retrieves it from the memory into the CPU’s instruction register. This process is essential for the CPU to know which instruction to execute next.

2. Instruction Decoding:
Once an instruction is fetched, the Control Unit decodes it to understand the specific operation to be performed. It interprets the instruction and determines the sequence of micro-operations required to execute it. This involves breaking down the instruction into its constituent parts, such as the opcode (operation code) and operands, to determine the type and parameters of the operation.

3. Instruction Execution Control:
After decoding the instruction, the Control Unit issues control signals to various components within the CPU to carry out the required operations. It coordinates the timing and sequencing of these operations to ensure correct execution. The Control Unit sends signals to the Arithmetic Logic Unit (ALU), registers, and other functional units to perform calculations, data manipulations, and logical operations as instructed by the current instruction.

4. Data Movement and Storage:
The Control Unit manages the movement and storage of data within the CPU and between the CPU and other parts of the computer system. It controls the flow of data between registers, memory, and input/output devices. The Control Unit ensures that data is transferred to the appropriate locations as instructed by the program being executed.

5. Branching and Control Transfer:
The Control Unit handles branching and control transfer instructions, which determine the flow of execution in a program. It evaluates conditions specified by these instructions and makes decisions on whether to execute the next instruction sequentially or branch to a different part of the program. This capability allows for conditional execution, loops, and decision-making within programs.

6. Synchronization and Timing:
The Control Unit maintains synchronization and timing within the CPU and across the system. It ensures that operations are executed in the correct order and at the appropriate time. It synchronizes the activities of different components and ensures that data dependencies and hazards are properly managed to prevent errors or conflicts.

Overall, the Control Unit acts as the “traffic controller” of the computer system, coordinating the flow of instructions and data between different components. It fetches instructions, decodes them, and issues control signals to enable the CPU and other hardware components to execute the instructions accurately and in the correct sequence. The Control Unit plays a vital role in ensuring the efficient and effective operation of the computer system as a whole.


The Arithmetic and Logic Unit (ALU) is a fundamental component of the Central Processing Unit (CPU) that performs arithmetic operations and logical comparisons. It is responsible for carrying out various mathematical calculations and logical evaluations required by computer programs. Let’s expand on the role and functions of the ALU:

1. Arithmetic Operations:
The ALU performs a range of arithmetic operations, such as addition, subtraction, multiplication, and division. It can handle both integer and floating-point operations, depending on the design of the CPU. The ALU operates on binary numbers, manipulating the bits to perform calculations. It utilizes circuits and logic gates to perform these operations efficiently and accurately.

2. Logic Operations:
In addition to arithmetic operations, the ALU also performs logical operations. These operations involve comparing two values or conditions and producing a logical result. Common logical operations include AND, OR, NOT, and XOR. The ALU’s logic circuits can evaluate logical expressions, make comparisons, and determine the truth or falsity of logical statements.

3. Decision-Making:
The ALU plays a vital role in decision-making within a computer system. It enables the CPU to perform conditional branching and make decisions based on the results of logical comparisons. For example, if the ALU evaluates that one value is less than another, the CPU can branch to a specific instruction or perform a particular action based on that comparison. This capability allows programs to execute different instructions depending on certain conditions or variables.

4. Bit-wise Operations:
The ALU can also perform bit-wise operations, manipulating individual bits within binary data. Bit-wise operations include shifting bits left or right, rotating bits, and masking specific bits. These operations are often used for data manipulation, encoding, and decoding purposes.

5. Flags and Status Bits:
The ALU sets various flags or status bits based on the arithmetic and logic operations results. These flags indicate specific conditions or outcomes of the operations. Common flags include a carry flag, zero flag, overflow flag, and sign flag. The CPU can check these flags to make further decisions or perform subsequent operations based on the outcomes of previous operations.

6. Performance Optimization:
Modern CPUs often employ advanced ALU designs and techniques to optimize performance. These include parallel processing, pipelining, and superscalar architectures. These optimizations allow the ALU to perform multiple operations simultaneously or overlap the execution of different instructions, thereby enhancing the overall speed and efficiency of the CPU.

In summary, the ALU is a crucial component of the CPU responsible for carrying out arithmetic operations, logical comparisons, and decision-making within a computer system. It performs calculations, evaluates logical expressions, sets flags, and enables the CPU to execute different instructions based on specific conditions. The ALU’s capabilities and performance greatly influence the overall computational power and efficiency of a computer.


The Memory Unit, also known as primary storage or main memory, is a crucial component of a computer system where programs and data are stored for immediate access by the CPU. It provides temporary storage for both instructions and data that are actively being processed. Let’s expand on the two main types of computer memory:

1. Random Access Memory (RAM):
Random Access Memory (RAM) is a volatile memory type that provides temporary storage for data and instructions that the CPU needs to access quickly. RAM allows for fast read and write operations, which are essential for the smooth execution of programs. When a computer is powered off or restarted, the data stored in RAM is lost. Key features of RAM include:

– Fast Access: RAM enables the CPU to quickly read and write data. It provides random access, meaning that any memory location can be accessed directly, without the need to access preceding locations sequentially.

– Volatility: RAM is volatile, meaning that its contents are lost when the power supply is turned off or interrupted. This characteristic allows RAM to be quickly overwritten and reused for different data and instructions.

– Capacity and Expandability: The amount of RAM in a computer determines its capacity for running programs and multitasking efficiently. RAM capacity can typically be expanded by adding more memory modules or upgrading existing ones.

– Types of RAM: There are various types of RAM, including Dynamic RAM (DRAM), Static RAM (SRAM), and Synchronous Dynamic RAM (SDRAM). Each type has its own characteristics in terms of speed, power consumption, and cost.

2. Read-Only Memory (ROM):
Read-Only Memory (ROM) is a non-volatile memory type that stores data and instructions that are permanently written during manufacturing. It contains firmware and software instructions that provide essential functions for booting up the computer and initializing hardware components. Key features of ROM include:

– Non-Volatility: Unlike RAM, ROM retains its contents even when the computer is powered off or restarted. The data stored in ROM is non-modifiable and can only be read.

– Firmware and Initialization: ROM contains firmware, such as the computer’s BIOS (Basic Input/Output System) or firmware for other devices like graphics cards. This firmware is responsible for low-level hardware initialization and providing basic functions for the computer system.

– Types of ROM: There are different types of ROM, including Programmable Read-Only Memory (PROM), Erasable Programmable Read-Only Memory (EPROM), and Electrically Erasable Programmable Read-Only Memory (EEPROM). These types vary in terms of their ability to be programmed or erased by the user.

– BIOS and System Initialization: The BIOS stored in ROM plays a critical role during the boot process, as it initializes the hardware, performs system checks, and loads the operating system into RAM for execution.

Both RAM and ROM work together to provide the necessary storage for the smooth operation of a computer system. RAM facilitates the quick access and manipulation of data during program execution, while ROM stores essential firmware and software instructions needed for system initialization and operation.


Peripherals are external devices that connect to the computer system and operate under the control of the CPU. They extend the functionality of the computer by providing input, output, or auxiliary capabilities. Peripherals allow users to interact with the computer and facilitate data transfer between the computer and external devices. Let’s expand on the different types of peripherals:

1. Input Devices:
Input devices allow users to provide data and commands to the computer system. They enable users to input information or instructions for processing. Common input devices include:

– Keyboard: A keyboard is a primary input device that allows users to enter text, numbers, and commands by pressing keys.

– Mouse: A mouse is a pointing device that allows users to control the movement of a cursor on the screen. It provides a graphical interface for selecting and manipulating objects.

– Scanner: Scanners are devices that convert physical documents or images into digital formats, allowing them to be stored or edited on a computer.

– Microphone: Microphones capture audio input, enabling users to record voice, participate in voice-based communication, or use voice recognition software.

– Webcam: Webcams capture video input, allowing users to participate in video conferencing, record videos, or take pictures.

2. Output Devices:
Output devices display or present information processed by the computer system. They provide users with the results or outputs of their interactions with the computer. Common output devices include:

– Monitor: A monitor, also known as a display or screen, presents visual information generated by the computer. It allows users to view text, images, videos, and graphical interfaces.

– Printer: Printers produce hard copies of digital documents or images on paper or other physical media. They are used for producing documents, images, and reports.

– Speakers: Speakers provide audio output, allowing users to listen to music, sounds, and audio from videos or voice-based applications.

– Projector: Projectors display images or videos onto a larger screen or surface, enabling presentations, movie screenings, or large-scale visual displays.

3. Storage Devices:
Storage devices allow for the storage, retrieval, and preservation of data. While storage devices can be considered both peripherals and components of the computer system, they are typically external to the CPU. Common storage devices include:

– Hard Disk Drives (HDD): HDDs provide high-capacity storage for long-term data storage. They use rotating magnetic disks to store and retrieve data.

– Solid-State Drives (SSD): SSDs also provide high-capacity storage but use flash memory instead of rotating disks. SSDs offer faster access times and are more resistant to shock and vibration.

– External Hard Drives: External hard drives are portable storage devices that connect to the computer system via USB or other interfaces. They provide additional storage capacity and allow for data backup or transfer.

– USB Flash Drives: USB flash drives, also known as thumb drives or pen drives, are small and portable storage devices that connect to the computer’s USB port. They are used for storing and transferring data between computers.

4. Other Peripherals:
There is a wide range of other peripherals available, each serving specific purposes or providing specialized functionalities. Some examples include:

– Graphics Tablets: Graphics tablets are input devices used by artists and designers to create digital artwork by drawing directly on a tablet surface with a stylus.

– Game Controllers: Game controllers enable users to interact with and control video games, providing buttons, joysticks, and other input mechanisms tailored for gaming.

– External Sound Cards: External sound cards enhance audio capabilities, providing better sound quality and additional audio connectivity options.

– Network Interface Cards (NIC): NICs enable computers to connect to wired or wireless networks, facilitating data communication and internet connectivity.

– Barcode Scanners: Barcode scanners read barcodes on products, allowing for quick and accurate data entry in retail, inventory management, and other applications.

– Biometric Devices: Biometric devices, such as fingerprint scanners or facial recognition cameras, provide secure and convenient methods for user authentication and access control.

Peripherals significantly enhance the functionality and usability of a computer system. They enable users to input data, receive output, store and retrieve information, and interact with various applications and devices. Peripherals work in conjunction with the CPU and software to provide a complete and versatile computing experience.


Software is a crucial component of a computer system that consists of programs and instructions used to direct the computer hardware and perform specific tasks. It enables users to interact with the computer, run applications, and accomplish various tasks. Let’s expand on the concept of software:

1. Programs and Instructions:
Software is composed of programs, which are sets of instructions written in programming languages. These instructions provide step-by-step guidance to the computer hardware, specifying the actions to be performed to achieve a particular goal or solve a specific problem. Programs are designed to perform various functions, ranging from simple calculations to complex operations.

2. Types of Software:
The software can be categorized into different types based on its purpose and functionality:

– System Software: System software refers to programs that manage and control the computer system itself. This includes the operating system (such as Windows, macOS, Linux), which provides a platform for running other software and manages system resources. The system software also includes device drivers that enable communication between hardware components and the operating system.

– Application Software: Application software consists of programs designed to perform specific tasks or provide certain functionalities. Examples include word processors, spreadsheets, web browsers, media players, graphic design software, and computer games. Application software allows users to accomplish a wide range of tasks, from creating documents and managing finances to editing images and playing games.

– Utility Software: Utility software includes programs that perform specific tasks to enhance system performance, manage resources, or provide maintenance functions. Examples include antivirus software, disk defragmenters, file compression tools, backup software, and system diagnostic tools. Utility software helps optimize the computer system and ensure its smooth operation.

– Programming Software: Programming software provides tools and environments for creating, editing, and debugging software programs. These tools include text editors, integrated development environments (IDEs), compilers, debuggers, and interpreters. Programming software enables software developers to write, test, and refine programs.

3. Execution of Software:
When a program is executed, the software instructions are loaded into the computer’s memory (RAM) from storage devices. The CPU then fetches each instruction and executes it, following the sequence of steps defined in the program. The instructions interact with the computer hardware, including the CPU, memory, and peripheral devices, to carry out specific operations.

4. Software Development:
Software development involves the process of designing, coding, testing, and maintaining software programs. Software developers or programmers use programming languages, libraries, and development tools to create software that meets specific requirements. The development process includes analysis, design, implementation, and testing to ensure the software functions correctly and efficiently.

5. Software Distribution and Licensing:
Software is typically distributed as executable files or installation packages that users can install on their computers. The software can be obtained through various means, such as physical media (CDs, DVDs) or digital distribution platforms (app stores, online downloads). Software developers may apply licensing terms to control the usage, distribution, and modification of their software.

Software is a collection of programs and instructions that direct the computer hardware to perform specific tasks. It encompasses system software, application software, utility software, and programming software. The software enables users to accomplish tasks and provides the functionality and capabilities of a computer system. It is developed through programming and executed by the CPU to carry out the defined operations.


Sizes of Microcomputer are laptop, palmtop, hand top, desktop, tower, etc.


  4. MOUSE


A computer is an electronic machine that accepts data as input, processes the data, and gives out information under the control of stored programs. The information which the computer gives out is called OUTPUT.

There are three keywords to note in the definition:


This is the physical aspect of a computer known as computer hardware. It consists of electronic and electro-mechanical parts working together to process data.


  1. It accepts data (input).
  2. It processes data (processing).
  3. It supplies information (output).


A program is a set of instructions that tells the computer to perform a given task. A computer does not understand English or any of the Nigerian languages. Rather it has its own language called PROGRAM.


The microcomputer is divided into three main parts namely:

  1. Central Processing Unit (CPU)
  2. Monitor
  3. Keyboard

Read also:

Digitalization of Data

Classification of Computers By Size

Classification of Computer By Types

History of Computers

Generations of Computers

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