Basics of Computer

A brief history of the development of computers, Definition of Computer, Block diagram of a Computer, Hardware, Software, Booting: Cold and Hot Booting, Interaction between the CPU and Memory with Input/Output devices, Function of CPU and major functional parts of CPU. Memory, Bit, Nibble, Byte, KB, MB, GB, TB, PB, Functions of memory, Use of storage devices in a Computer, List types of memory used in a Computer, Importance of cache memory, CPU speed and CPU word length.

Definition of Computer: A computer is a machine programmed to automatically carry out sequences of arithmetic or logical operations (computation). Modern digital electronic computers perform operations known as programs. These programs enable computers to perform a wide range of tasks.

Block diagram of a computer

+-----------------+ +-----------------+ +-----------------+ +-----------------+

| Input |---->           | Central Processing|---->| Output |---->| Storage |

| Unit | | Unit (CPU) | | Unit | | Unit |

+-----------------+ +-----------------+ +-----------------+

^ | | |                                 | | | |                        | v v v

| +-----------------+ +-----------------+ +-----------------+ +-----------------+

| | Arithmetic & |         | Control Unit |         | Memory Unit |      | | Logic Unit | | | | |

| | (ALU) | | | | |

+-----------------+ +-----------------+ +-----------------+ +-----------------+

| Registers |

+-----------------+

Explanation of the components:

1. Input Unit: This is data and instructions entering the computer. Examples include the keyboard, mouse, scanner, microphone, etc.

2. Central Processing Unit (CPU): The "brain" of the computer. It executes instructions and performs calculations. It's comprised of:

   a. Arithmetic & Logic Unit (ALU): Performs mathematical calculations (addition, subtraction, etc.) and logical comparisons (greater than, less than, etc.).

   b. Control Unit: Directs the data flow within the computer, fetches instructions from memory, and decodes them.

   c. Registers: Small, high-speed storage locations within the CPU used to hold data and instructions currently processed.

3. Output Unit: Displays or presents the processing result. Examples include the monitor, printer, speakers, etc.

4. Storage Unit (Memory): Holds data and instructions before, during, and after processing. This includes:

5. Memory Unit (Primary Memory/RAM): Volatile storage where data is actively being used or processed. Data is lost when the computer is turned off.

6. Secondary Storage (Not shown in detail): Non-volatile storage for long-term data storage. Examples include hard drives, SSDs, USB drives, etc. Data persists even when the computer is turned off.

The arrows in the diagram indicate the flow of data and control signals between the different units. The CPU is the central hub, controlling all operations.

Computer hardware: It refers to all the physical components that make up a computer system. These are the parts that can be seen and touched. They work together to execute instructions and process data. The following are some key hardware components:

1.  Internal Hardware:

   a. Central Processing Unit (CPU): The "brain" of the computer, responsible for executing instructions and performing calculations.

   b. Motherboard: The main circuit board that connects all the other components.

   c. Random Access Memory (RAM): Temporary memory that holds data and instructions that the CPU is actively using.

   d. Storage Devices: These store data permanently. Examples include:

        i. Hard Disk Drives (HDDs): Traditional storage devices that use spinning platters to store data.

        ii. Solid State Drives (SSDs): The faster reliable storage devices with no moving parts.

        iii.  Graphics Card (GPU): Processes and displays images and videos.

        iv. Sound Card: Processes audio.

        v. Power Supply Unit (PSU): Provides power to all the components.

2. External Hardware:

   a. Input Devices: Allow you to interact with the computer. Examples include Keyboard, Mouse, Touchscreen, Microphone, and Scanner.

         b. Output Devices: Display or present information from the computer. Examples include Monitors, Printers, Speakers, Projector

Key Considerations:

• 1. Compatibility: Hardware components need to be compatible with each other to work properly.

• 2. Performance: The performance of a computer system depends on the quality and speed of its hardware components.

• 3. Upgradability: Many hardware components can be upgraded to improve performance or add new features.

Computer hardware is constantly evolving, with new technologies and advancements being developed all the time.24 Understanding the basics of computer hardware is essential for anyone who wants to build, use, or troubleshoot a computer system.

Computer software:

Computer software is the set of instructions, data, or programs for a computer. Computer software is the intangible part of a computer system that allows users to interact with the hardware and perform specific tasks. It is the bridge between you and the computer's hardware.

Types of Software: The Software has two types

• 1. System Software: This software manages the computer's hardware and provides a platform to run software applications. System software is an important piece of the operating system (OS), such as Windows, macOS, or Linux. Other examples include device drivers and utility programs.

• 2. Application Software: This software is designed to perform specific tasks for the user. It includes a wide range of programs, such as word processors (e.g., Microsoft Word), web browsers (e.g., Chrome), games, and graphics editors (e.g., Photoshop).

Functions of Software/Importance of Software

Software is essential for any computer system to function. Without software, the hardware would be useless.

1. Instructions: Software provides step-by-step instructions to a computer to execute tasks.

2. User Interface: Software often provides a user interface (UI) that allows users to interact with the computer in a user-friendly way.

3. Functionality: Software provides the functionality that allows users to accomplish specific goals. It is writing a document, browsing the web, or playing a game.

4. Communicate with computers

5. Perform tasks efficiently

6. Access information

7. Create and edit content

8. Entertain ourselves

Software Development: Software is created by programmers using programming languages. Developing software can be complex and involves many stages, including Planning, Design, Coding, Testing, Deployment, and Maintenance. Software is constantly evolving, with new programs and updates being released regularly. It's a dynamic and essential part of the computing world.

Booting: Cold Booting and Hot Booting.

Booting is the process of starting up a computer. Booting is the sequence of events that turns on the power and ends when the operating system is ready. There are two main types of booting:

1. Cold Booting: A cold booting turns on a completely powered-off computer. It's a fresh start.

   Process: The computer's BIOS (Basic Input/Output System) or UEFI (Unified Extensible Firmware Interface) performs a Power-On Self-Test (POST) to check the hardware components (memory, keyboard, etc.). Then, the boot loader program locates and loads the operating system from the storage device (hard drive, SSD, etc.) into RAM. Finally, the OS takes over, initializes drivers, and presents the user interface.

   Analogy: Like starting a car that's been parked for a while.

2. Hot Booting (Warm Booting): A hot boot (or warm boot) occurs when you restart a computer that is already running. It's a reboot.

   Process: The operating system is already in memory. So, the POST is usually skipped or shortened. The system restarts from a known state, often after a software crash or update. The OS performs a quicker reset, and the user is typically logged back in faster                                                                                                             . Analogy: Like restarting a car that's already warm.

Key Differences Summarized:

Features of Cold Boot

1. Starting State: The computer is completely powered off.

2. POST: Full POST is performed.

3. Speed: Slower

4. Purpose: Initial startup, hardware check.

Features of Hot Boot (Warm Boot)

1. Starting State: The computer is running (or was running).

2. POST: POST is often skipped or abbreviated.

3. Speed: Faster

4. Purpose: Restart after crash, software update, etc.

Interaction between the CPU and Memory with Input/Output devices.

The following are the CPU, memory, and input/output (I/O) devices that interact:

1. The Central Processing Unit (CPU): The Conductor. The CPU is the "brain" of the computer. It executes instructions and performs calculations. It fetches instructions and data from memory. It processes the data and sends results back to memory or to output devices. “The CPU is the central hub, controlling the data flow.”

2. Memory (RAM): The Stage. The CPU keeps the data and instructions in the memory (specifically Random Access Memory or RAM). It's like the stage where the CPU performs its operations. Data and instructions are loaded into RAM from storage devices (like hard drives) when a program is running. “Memory acts as a temporary holding place for data and instructions.”

3. Input/Output (I/O) Devices: The Actors. I/O devices allow the computer to interact with the outside world.

   a. Input devices: These provide data to the computer. Examples: keyboard, mouse, microphone.

   b. Output devices: These display or present the processing result. Examples: monitor, printer, speakers.

The Interaction: This interaction is happening constantly and at high speeds. It helps to use computers for a wide range of tasks.

1. Input: The keyboard (input) is used to type. The keyboard sends this data to the CPU.

2. CPU and Memory: The CPU stores this data in memory. It might also fetch instructions from memory to process the data (e.g., to display it on the screen).

3. Processing: The CPU processes the data according to the instructions.

4. Output: The CPU sends the processed data to the output device (the monitor) and then displays the characters you typed.

Think of it like this:

• · You (the user) are like the input device.

• · The CPU is the director, telling everyone what to do.

• · Memory is the stage where the action happens.

• · The output device is like the screen where the performance is shown.

The Central Processing Unit (CPU) is the "brain" of a computer. Its primary function is to execute instructions and perform calculations. It's responsible for everything from running applications to managing hardware. Think of it as the conductor of an orchestra, directing all the other parts of the computer.

Function of CPU and major functional parts of CPU.

The following are the major functional parts of a CPU:

1. Arithmetic Logic Unit (ALU): This is where the actual "work" happens. The ALU performs all the arithmetic operations (addition, subtraction, multiplication, division) and logical operations (comparisons like greater than, less than, equal to). It's the calculator of the CPU.

2. Control Unit (CU): The CU is the "manager" of the CPU. It directs the flow of data and instructions within the CPU and controls the timing and sequence of operations. It fetches instructions from memory, decodes them, and then tells the ALU what to do.

3. Registers: These are small, high-speed storage locations within the CPU. They hold data and instructions that the CPU is currently working on. They are the CPU's short-term memory. The access is extremely fast because registers are inside the CPU.

How they work together:

• · The CU fetches an instruction from memory.

• · The CU decodes the instruction to understand what it needs to do.

• · If the instruction involves calculations, the CU sends the data to the ALU.

• · The ALU performs the calculation.

• · The result is stored back in a register or in memory.

• · The CU then fetches the next instruction.

This cycle repeats over and over again, allowing the CPU to execute complex programs and process vast amounts of data. The speed at which the CPU can perform these operations is a major factor in the overall performance of a computer.

Memory, Bit, Nibble, Byte, KB, MB, GB, TB, PB.

How do computers store and manipulate information?

The following is the breakdown of memory and its units:

1. Memory: The Computer's Workspace. The memory of the computer holds data and instructions. These are actively used or processed. Think of it as the computer's workspace or short-term storage. There are different types of memory, but the most common is RAM (Random Access Memory).

2. Units of Memory: From Tiny Bits to Massive Petabytes. Memory is measured in units that represent the data it can hold. The following are the common units, from smallest to largest:

   a. Bit: The smallest unit of data. It can be either a 0 or a 1. Think of it as a light switch that can be either on (1) or off (0).

   b. Nibble: A group of 4 bits.

   c. Byte: A group of 8 bits. A byte is the fundamental unit for measuring data storage.8 It can represent a single character (like a letter or number).

   d. Kilobyte (KB): 1,024 bytes.

   e. Megabyte (MB): 1,024 kilobytes.

   f. Gigabyte (GB): 1,024 megabytes.

   g. Terabyte (TB): 1,024 gigabytes.

   h. Petabyte (PB): 1,024 terabytes.

Functions of Memory

1. Storing Data: Memory holds the data that the computer is currently working with. This could be anything from a document to the instructions for a program that's running.

2. Storing Instructions: Memory also holds the instructions that tell the computer what to do. These instructions are part of programs or the operating system.

3. Fast Access: Memory allows the CPU to access data and instructions quickly, which is essential for efficient processing.

The larger the unit (KB, MB, GB, etc.), the more data the memory can hold. Different types of memory have different speeds and purposes. RAM is fast but temporary, while hard drives are slower but can store data permanently. Understanding memory and its units is crucial for understanding how computers work and for choosing the right storage solutions for your needs.

Use of storage devices in a computer

Storage devices are essential components of a computer system. It serves as the long-term memory where data and programs are kept. The following are their main uses:

1. Storing Programs and Applications: Storage devices hold the software that makes your computer useful. This includes the operating system (like Windows or macOS), applications (like web browsers, word processors, and games), and all the other programs used in the computer.

2. Saving Data: Storage devices provide a place to save your data. It may be documents, photos, videos, music, or any other type of file. This allows us to keep work, memories, and important information safe and accessible.

3. Archiving Information: Storage devices are used to archive data that may not need to be accessed regularly but need to be kept for future reference. This could include old projects, financial records, or backups of important files.

4. Loading and Running Programs: When a program is launched, it's loaded from the storage device into the computer's memory (RAM) so that the CPU can execute it.

5. Transferring Data: Storage devices such as portable ones like USB drives or external hard drives are used to transfer data between computers.

Types of Storage Devices:

1. Hard Disk Drives (HDDs): Traditional storage devices that use spinning platters to store data. They offer large capacities at relatively low cost.

2. Solid State Drives (SSDs): Faster and more reliable storage devices with no moving parts. They offer quicker access to data and improved performance.

3. Optical Discs (CDs, DVDs, Blu-rays): They are less common now but still used for some purposes like distributing software or backing up data.

4. USB Flash Drives: Portable storage devices that connect to a computer via a USB port. They are convenient for transferring files and storing small amounts of data.

5. 5. Memory Cards: Used in cameras, smartphones, and other devices to store photos, videos, and other data.

The following points should be considered while selecting storage devices:

• · Capacity: How much data the storage device can hold.

• · Speed: How quickly data can be read from and written to the storage device.

• · Portability: Whether the storage device can be easily moved between computers.

• · Cost: The price of the storage device.

Storage devices play a crucial role in the overall functionality and usability of a computer. It enables us to store, access, and manage our digital information effectively.

List the types of memory used in a computer,

The following are the different types of memory that a computer uses.

1. 1. Primary Memory (Main Memory)

   a. Random Access Memory (RAM): This is the computer's working memory. It holds data and instructions that the CPU is actively using. RAM is volatile, meaning its contents are lost when the computer is turned off. There are two main types of RAM.

         i. Static RAM (SRAM): Faster and more expensive, used for cache memory.

          ii. Dynamic RAM (DRAM): Slower and less expensive, used for main system memory.

   b. Read-Only Memory (ROM): Stores permanent or semi-permanent instructions that the computer needs to start up and operate. ROM is non-volatile, meaning its contents are retained even when the power is off. There are three types of ROM.

         i. PROM (Programmable ROM): It can be programmed once by the user.

        ii. EPROM (Erasable Programmable ROM): It can be erased and reprogrammed (using UV light).

        iii. EEPROM (Electrically Erasable Programmable ROM): It can be erased and reprogrammed electrically.

2. 2. Secondary Memory (Auxiliary Memory): This is used for long-term storage of data and programs. Secondary memory is non-volatile. Examples include:

   a. Hard Disk Drives (HDDs): Magnetic storage devices.

   b. Solid State Drives (SSDs): Use flash memory to store data.

   c. Optical Discs (CDs, DVDs, Blu-rays): Use lasers to read and write data.

   d. USB Flash Drives: Portable storage devices that connect via USB.

3. 3. Cache Memory A small, very fast type of memory located within or close to the CPU.

Stores frequently access data and instructions, allowing the CPU to access them quickly. It improves overall system performance.

   4. Virtual Memory: A technique that allows the computer to use secondary storage (like a hard drive) as if it were RAM. Useful when the computer needs to run more programs or handle more data than can fit in RAM.

Main Differences:

Features of RAM

1. Volatility: Volatile (data lost when power is off)

2. Speed: Fast

3. Purpose: Holds data and instructions currently in use

Features of ROM

1. Volatility: Non-volatile (data retained)

2. Speed: Slower than RAM

3. Purpose: Stores permanent instructions

Features of Secondary Memory

1. Volatility: Non-volatile

2. Speed: Much slower than RAM

3. Purpose: Long-term storage of data and programs

Understanding the different types of memory is important for understanding how computers work and for choosing the right memory and storage solutions for your needs.

Importance of cache memory, CPU speed and CPU word length.

A. Importance of Cache Memory

1. Speed Boost: Cache memory is like a high-speed "middleman" between the CPU and main memory. It stores frequently used data and instructions, allowing the CPU to access them much faster than if it had to retrieve them from RAM every time. This significantly reduces the time the CPU spends waiting for data, leading to faster overall performance.

2. Reduced Latency: Accessing data from RAM can be relatively slow compared to accessing it from cache. Cache memory reduces this latency, allowing the CPU to process information more quickly and efficiently.

3. 3. Improved CPU Utilization: By providing the CPU with quick access to frequently used data, cache memory helps to keep the CPU busy and working, rather than waiting for data to arrive. This improves CPU utilization and overall system efficiency.

B. Importance of CPU Speed:

1. Clock Speed: CPU speed is often measured in gigahertz (GHz). This indicates how many instructions the CPU can execute per second. A higher clock speed generally means the CPU can process more instructions in a given time. It leads to faster performance.

2. Processing Power: CPU speed is a major factor in determining how quickly a computer can perform tasks, such as running applications, processing data, and responding to user input.

3. Generational Improvements: In addition to clock speed, CPU speed is also influenced by architectural improvements that allow CPUs to process more instructions per clock cycle.

C. Importance of CPU Word Length

1. Data Handling: CPU word length refers to the number of bits that a CPU can process at one time. A longer word length means the CPU can handle larger chunks of data in a single operation.

2. Efficiency: A CPU with a longer word length can often process data more efficiently. It is especially useful when dealing with large data sets or complex calculations.

3. Addressing Memory: Word length also affects how much memory a CPU can address. A longer word length allows the CPU to access a larger range of memory locations.

How Do They Work Together?

Three factors work together to influence a computer's overall performance:

• · Cache memory helps to keep the CPU fed with data and instructions quickly.

• · CPU speed determines how fast the CPU can process those instructions,

• · CPU word length affects how much data the CPU can handle.

By optimising these factors, computer manufacturers can create systems that are faster, more efficient, and capable of handling increasingly complex tasks.

Alok Bains