Solid State Drive (SSD)

SSD (Solid State Drive) is a type of storage device used in computers to store data permanently. Unlike traditional hard disk drives (HDD), an SSD uses flash memory and has no moving mechanical parts.

SSDs are faster, more reliable, and consume less power compared to HDDs.

Working Principle of SSD

The working principle of an SSD is based on NAND flash memory technology.

• Data is stored in memory cells made of floating-gate transistors.
• These cells store electrical charges to represent binary data (0 and 1).
• A controller inside the SSD manages reading, writing, and storing data.
• When the computer requests data, the SSD controller quickly retrieves it from the flash memory without any mechanical movement.
• This electronic process allows SSDs to access data much faster than traditional hard drives.

Comparison Between CPU and GPU

• Definition: CPU (Central Processing Unit) is the main processor of a computer responsible for executing general instructions. GPU (Graphics Processing Unit) is a processor designed mainly for graphics rendering and parallel processing.
• Number of Cores: CPU has a small number of powerful cores, while GPU has a large number of smaller cores for parallel tasks.
• Processing Type: CPU performs sequential processing and handles a variety of tasks. GPU performs parallel processing and handles many similar tasks simultaneously.
• Usage: CPU is used for general computing tasks such as running programs and operating systems. GPU is mainly used for graphics rendering, gaming, video processing, and machine learning.
• Performance: CPU is optimized for low-latency tasks, while GPU provides high throughput for large-scale parallel computations.

i) Virtual Memory:
Virtual memory is a memory management technique that allows a computer to use part of the secondary storage (hard disk or SSD) as if it were additional RAM. When the main memory (RAM) becomes full, the operating system temporarily transfers some data from RAM to secondary storage. This allows the system to run larger programs and multiple processes even when physical RAM is limited.

ii) Cache Memory:
Cache memory is a small, high-speed memory located close to the CPU. It stores frequently used data and instructions so that the CPU can access them quickly. Because cache memory is much faster than main memory (RAM), it helps improve the overall performance of the computer.

Polymorphism is an important concept of Object-Oriented Programming (OOP) where a single function or method can perform different tasks depending on the context. The word polymorphism means “many forms”. It allows the same interface to be used for different data types or objects.

Polymorphism mainly occurs in two ways:

1. Method Overloading

Method overloading occurs when multiple methods have the same name but different parameters (different number or type of arguments) in the same class. It is an example of compile-time polymorphism.

Example:

class Calculator {
    int add(int a, int b) {
        return a + b;
    }

    int add(int a, int b, int c) {
        return a + b + c;
    }
}

In this example, the method name add() is the same, but the number of parameters is different.

2. Method Overriding

Method overriding occurs when a child class provides a specific implementation of a method that is already defined in its parent class. It is an example of runtime polymorphism.

Example:

class Animal {
    void sound() {
        System.out.println("Animal makes sound");
    }
}

class Dog extends Animal {
    void sound() {
        System.out.println("Dog barks");
    }
}

Here, the Dog class overrides the sound() method of the Animal class to provide its own behavior.