mmap, short for memory map, is an operating system mechanism that maps a file or device directly into a process’s virtual memory address space. Instead of reading file data explicitly with read() into a buffer, the application can access the file as if it were an array in memory. The operating syste...
HTTP caching is the process of storing copies of HTTP responses so that future requests can be served without contacting the origin server. It operates at multiple layers — the browser, intermediate proxies, reverse proxies, and CDN edge nodes — and is controlled primarily through standardised HTTP ...
Geostatistics is a branch of statistics devoted to the analysis and interpretation of spatial or spatiotemporal datasets. This field finds applications in geology, hydrology, environmental science, agriculture, meteorology, and many other areas where data vary across space. The techniques of geostat...
Point processes are mathematical models that help us understand random collections of points distributed in time, space, or both. They provide a powerful framework for studying events such as the occurrence of earthquakes, the locations of trees in a forest, or the arrival times of customers at a se...
Spatial autocorrelation describes how similar or dissimilar values of a variable are arranged across geographic space. This concept builds on the idea that nearby locations tend to have related characteristics, a principle often summarized by Tobler’s First Law of Geography: “Everything is related t...
Tags mark exact commits. They’re perfect for releases, rollbacks, changelogs, and CI/CD triggers. Unlike branches, tags don’t move—ever—so you can always point to the exact build you shipped...
Before choosing a branching strategy, it helps to decide what you’re optimizing for: speed, safety, or simplicity. Different teams and projects lean different ways—startups with small codebases won’t work the same as larger, multi-repo setups. This overview lays out the options and how to adapt them...
Git is a powerful tool, but its complexity often puzzles newcomers. Let’s break down some typical areas where users get tripped up in simpler terms...
HEAD is Git’s pointer to the snapshot you’re currently working on—the bookmark of your checkout. Most of the time, HEAD points to the tip of a branch (like master or main). When you commit, HEAD (and that branch) advance to the new commit...
Git branches are lightweight names that point to commits. Think of them as parallel timelines: you can try ideas on a branch without touching main, then merge back when you’re happy...
When managing software projects, organizations often need to choose between two distinct codebase structuring strategies: monorepos and multirepos. This decision isn’t just about where code lives—it affects collaboration, tooling, versioning, and even deployment practices. When you’re starting out o...
In Git, you might accumulate multiple small commits over the course of developing a new feature, fixing small bugs, or refactoring code. While these incremental commits are crucial during active development, they can clutter the project history in the long term. This clutter becomes especially evide...
Working with files on Unix-based systems often involves managing multiple files and directories, especially when it comes to storage or transferring data. Tools like tar and gzip are invaluable for packaging and compressing files efficiently. Understanding how to use these commands can simplify task...
We will discuss various tools that can be used on Linux systems for tasks such as taking screenshots, recording screens, preparing bootable sticks, and detecting malware. It provides brief explanations of each tool and includes installation and usage instructions...
Cron is a powerful utility in Unix-like operating systems that automates the execution of scripts or commands at specified times, dates, or intervals. It is used for tasks such as system maintenance, backups, updates, and more...
Inodes are critical as they store essential metadata about files, such as permissions and locations, allowing efficient file system management. Hard links are important because they let multiple file names point to the same inode, saving disk space by avoiding data duplication. Symlinks provide flex...
We will now delve deeply into the Linux kernel to understand its role in the operating system, where it resides on your system, and how kernel modules function. We will also explore how to download and examine the Linux kernel source code, and discuss the various configuration options available with...
In any operating system, a process is the fundamental unit of execution—a live instance of a program. Beyond its executable code (the text segment), a process encompasses its dynamic state: the program counter, CPU registers, call stack, heap, and other variable storage. To manage and schedule these...
One of the fundamental skills is to navigate and manage files and directories effectively. Here, we focus on the crucial concepts that will facilitate your work within the file system...
File permissions are crucial in any Unix-like operating systems, including Linux, which employ several mechanisms for controlling access to files and directories. These mechanisms include standard permissions, special permissions, and access control lists (ACLs)...
The Dynamic Window Manager (DWM) is a minimal, lightweight, and highly efficient tiling window manager designed to help you manage application windows in a clean and distraction-free manner. Instead of overlapping windows as seen in traditional window managers, DWM organizes windows in a tiled layou...
Linux is a versatile and powerful open-source operating system that forms the backbone of countless technological infrastructures, from servers and desktops to mobile devices and embedded systems. Known for its stability, security, and flexibility, Linux provides a robust platform that can be custom...
In Unix, files and filesystems are important components of the operating system's structure. A file is a collection of data stored on disk, which can include anything from text documents and images to executable programs. Files are organized within directories in a hierarchical structure, allowing f...
Input redirection (<) allows a command to read from a file, while output redirection (>) sends a command's output to a file. Streams like stdin, stdout, and stderr control the flow of data between commands and the system, where stdin is the input, stdout is the standard output, and stderr is the err...
Managing and monitoring disk usage is necessary for server maintenance, allowing administrators to identify disk space shortages caused by large log files, such as Apache or system logs, and malfunctioning applications that generate excessive data. Tools like df provide quick overviews of available ...
SSH, SFTP, and SCP are network protocols that provide secure data communication and file transfer over insecure networks. Here's a brief overview of each...
Debian and Ubuntu are popular Linux distributions for home users. These distributions and their derivatives use the Advanced Package Tool (APT). Other distributions use alternative package managers, like DNF, YUM, Pacman, which have unique functionalities and syntax...
Netlify allows you to easily deploy and manage static websites. A Python-based static site generator like Pelican, MkDocs, or Frozen-Flask produces HTML files that Netlify serves through its global CDN...
Digital Ocean provides cloud-based virtual machines called Droplets that let you deploy and manage CentOS servers. The overall flow looks like this...
Message queues enable asynchronous, decoupled communication in distributed systems by allowing publishers to send messages to a queue that consumers process independently, typically in first-in, first-out order. This approach reduces direct dependencies between services, enhances reliability and sca...
Operational Transform is a foundational technique in distributed systems that enables real-time collaborative editing of shared documents. Originally proposed by Ellis and Gibbs in 1989, OT allows multiple users to concurrently modify the same document while preserving consistency across all partici...
Linearizability is a consistency model that makes a distributed system appear as if there is only a single copy of the data, and every operation takes effect atomically at some point between its invocation and its response. Even when data is replicated across multiple nodes, a linearizable system gu...
Concurrent writes happen when two or more clients write to the same key in a database at the same time, each unaware of the other's write. In replicated systems, these writes may arrive at different replicas in different orders, causing the replicas to diverge and hold conflicting values. Without a ...
The Gossip Protocol is a peer-to-peer communication technique in distributed systems where nodes share information by randomly selecting partners and exchanging state, much like how rumors spread through a social network. It is especially useful in large clusters where nodes frequently join or leave...
Caching is a technique used to speed up data retrieval by placing frequently accessed or computationally heavy information closer to the application or the end user. Below is an expanded set of notes on caching, presented with ASCII diagrams and bullet points that emphasize key considerations. Each ...