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File Management in UNIX

UNIX is one of the most influential operating systems ever developed, forming the backbone of Linux, macOS, cloud servers, and enterprise systems. One of its greatest strengths is its simple, elegant, and powerful file system structure. This rewritten post explains file management, inodes, directories, system calls, links, IPC, processes, and memory management in UNIX , in a clear and modern style suitable for students, job seekers, and professionals. SECTION I – FILE MANAGEMENT IN UNIX 1. How UNIX Represents Devices In UNIX, everything is treated as a file . This includes keyboards, disks, terminals and other hardware components. All device files are stored inside the /dev directory and are classified as: ✔ Regular File A normal file that stores user data. ✔ Block Special File Represents block-oriented devices (like disks). Data transfers occur in blocks. ✔ Character Special File Represents character-based devices such as keyboards or serial ports, transferring data as a s...

Oracle PL/SQL Complete Guide

Oracle PL/SQL is one of the most powerful procedural extensions to SQL ever built. It has shaped enterprise applications for decades and continues to be deeply integrated into Oracle databases, cloud offerings, and modern data engineering workloads. This extensive guide covers everything you need to know about PL/SQL —from basic concepts to advanced features like dynamic SQL, triggers, external procedures, file handling, roles, mutating tables, debugging, and best coding practices. 1. Introduction to Oracle PL/SQL What is PL/SQL? PL/SQL (Procedural Language/Structured Query Language) is Oracle’s extension to standard SQL. While SQL is declarative and designed for querying data, PL/SQL adds imperative programming capabilities such as: Variables & constants Conditional statements Loops Functions & procedures Packages Exception handling Object-oriented features (encapsulation, overloading, information hiding) It enables developers to write complex, da...

The Evolution of Computing Hardware: From Tally Sticks to Multi-Core Chips

Computing hardware didn’t spring into being overnight — it’s the story of a long, relentless push to make machines faster, cheaper, and able to store ever more information. What began as simple human aids for counting gradually turned into programmable mechanical devices, then into electricity-driven machines, and finally into the microchip ecosystems that power everything around us today. This post walks through that journey: the inventiveness, the engineering breakthroughs, the key milestones, and why each step mattered.. Beginnings: Humans, Tally Marks and the Abacus Long before “computer” meant a machine, it meant a person who calculated. The earliest tools were simple and tangible — tally sticks, clay tokens, counting rods and the abacus — all one-to-one representations of quantities. These devices made bookkeeping and trade possible. Over centuries, the need to automate repetitive arithmetic led to increasingly clever mechanical aids. Mechanical Calculators and Programmable ...

Communication Process, Verbal and Non-Verbal Communication

Communication is one of the most essential skills in personal life, education, workplace, leadership, and society. Whether we speak, write, listen, or simply express through gestures, communication shapes the way we connect with people around us. The communication process is not merely the exchange of words—it is the transfer of ideas, emotions, thoughts, information, and meaning from one person to another. In today’s digital age, when humans communicate more than ever before through different platforms—phone calls, meetings, emails, social media, virtual offices—the ability to communicate effectively has become a key to success. Yet, communication is often misunderstood as “just talking.” In reality, communication is far more complex and involves verbal, non-verbal, visual, emotional, and psychological elements. This article provides a comprehensive understanding of: ✔ The communication process ✔ Verbal communication ✔ Non-verbal communication ✔ Importance and elements of speaki...