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Articles on Trending Technologies
Technical articles with clear explanations and examples
Semaphores in Operating System
Semaphores are integer variables used to solve the critical section problem through two atomic operations: wait and signal. They provide a synchronization mechanism that allows processes to coordinate access to shared resources safely. How Semaphores Work Semaphores use two fundamental operations that must be executed atomically (without interruption): Wait Operation The wait operation decrements the value of its argument S if it is positive. If S is zero or negative, the process blocks until the semaphore becomes positive. wait(S) { while (S
Read MoreCheck if Hard Drive is SSD or HDD on Linux
To determine whether our file system uses SSD or HDD technology, we need to identify which type of storage device is used by our Linux system. Understanding storage hardware helps optimize performance and make informed decisions about data placement. There are many different aspects of Linux storage with numerous tools available for reading and configuring storage devices. We use terms like "drive", "volume", and "mount point" to describe hard drives, optical discs, and USB sticks. To understand the underlying technology, we focus on two key aspects − What physical disk or block device we are examining (using ...
Read More20 Useful IPtable Firewall Rules Every Linux Administrator Should Know
As a Linux administrator, one of the most important aspects of maintaining a secure and stable network is implementing an effective firewall. IPtables is a powerful firewall tool that comes pre-installed on most Linux distributions. In this article, we will explore 20 useful IPtables firewall rules that every Linux administrator should know. These rules will help you secure your network and prevent unauthorized access, while also allowing legitimate traffic to pass through. Block All Incoming Traffic Except SSH The first rule is to block all incoming traffic except for SSH. SSH is a secure way to access your ...
Read MoreHow To Enable HTTPS for Varnish Cache using Hitch on CentOS/RHEL 8?
In today's world of internet security, enabling HTTPS on your website is crucial to ensure the privacy and safety of your users' data. One way to achieve this is by using Varnish Cache and Hitch, a lightweight TLS proxy, to offload SSL/TLS processing from Varnish. In this article, we will guide you through the process of enabling HTTPS for Varnish Cache using Hitch on CentOS/RHEL 8. Prerequisites Before we begin, ensure that you have the following − A CentOS/RHEL 8 server Root access to the server Varnish Cache and Hitch installed A valid SSL/TLS certificate ...
Read MoreHow to Find Files in Linux With the Find Command?
The find command is one of the most powerful and essential tools in Linux for locating files and directories within the filesystem. Unlike simple search utilities, the find command allows you to search based on various criteria such as file name, size, permissions, modification time, and even content. It recursively searches through directory hierarchies, making it invaluable for system administration and file management tasks. The find command works by traversing directories starting from a specified path and evaluating each file and directory against the given search criteria. Its flexibility lies in its ability to combine multiple search conditions and ...
Read MoreHow to Disable IPv6 in CentOS 8?
In today's modern world, the utilization of the Internet is essential for many businesses and individuals alike. The Internet Protocol (IP) is a fundamental communication protocol used to connect devices over the internet. Internet Protocol Version 6 (IPv6) was introduced in 1998 as an improvement over IPv4 and has since become more widely adopted. What is IPv6 and Why Disable It? IPv6 provides several advantages over its predecessor, including a larger address space (128-bit vs 32-bit), improved security features, and better network performance. However, there are situations where disabling IPv6 may be necessary: Some legacy applications ...
Read MoreHow to check total space and available space in Linux using the terminal?
In Linux/Unix systems, the df (disk free) command is the primary tool for checking storage details and disk space usage. It displays total space, used space, and available space for mounted file systems through the terminal. df (disk free) command The df command reports file system disk space usage in the Linux system. By default, it shows space usage in 1K blocks, but various options make the output more readable and useful for different purposes. Syntax The general syntax of the df command is as follows: $ df [OPTION]... [FILE]... Common Options ...
Read MoreMutex vs Semaphore
Mutex and Semaphore are both synchronization mechanisms used in operating systems to coordinate access to shared resources between multiple threads or processes. While they serve similar purposes, they have distinct characteristics and use cases. Mutex A Mutex (Mutual Exclusion) is a locking mechanism that ensures only one thread can access a critical section at a time. It acts like a binary lock that can be either acquired or released by a thread. How Mutex Works wait(mutex); // Critical Section // Only one thread can execute here signal(mutex); Key characteristics of Mutex: ...
Read MoreFind the Java SDK location on Linux
Finding the Java SDK location on Linux is a common task for developers who need to configure environment variables, set up IDEs, or manage multiple Java versions. This article demonstrates several reliable methods to locate your Java Development Kit (JDK) installation directory using built-in Linux commands. Understanding Java Installations on Linux On Linux systems, Java can be installed in various locations depending on the installation method and distribution. Common locations include /usr/lib/jvm/, /usr/java/, or /opt/java/. Additionally, many systems support multiple Java versions simultaneously, making it important to identify which version is currently active. Method 1: Using update-java-alternatives ...
Read More20 Useful PKG Command Examples to Manage Packages in FreeBSD
FreeBSD is a free and open-source Unix-like operating system based on Berkeley Software Distribution (BSD) system. It is widely used by developers, system administrators, and users who are looking for a reliable and secure operating system. One of the main features of FreeBSD is its package management system, which allows users to easily install, update, and remove software packages using the pkg command. Basic Package Management Commands 1. Installing Packages To install a package in FreeBSD, use the pkg install command followed by the package name − pkg install apache24 2. Updating All ...
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