Setting up call forwarding on iPhone Call forwarding redirects incoming calls to another number when you’re unavailable or expect to lose coverage. It’s a carrier-level feature (not dependent on iOS itself), so availability and behavior depend on your carrier’s implementation. Enable call forwarding Open Settings → Phone Tap Call Forwarding Toggle the switch to On…
HTML Entities Reference HTML entities represent characters that either have special meaning in HTML or aren’t easily typed. You have three syntax options: Named entity: &name; (e.g., ©) Decimal numeric: &#number; (e.g., ©) Hexadecimal numeric: &#xhexcode; (e.g., ©) With UTF-8 encoding (which you should always use), most special characters can be typed directly in your…
HTML Basics HTML (Hypertext Markup Language) is the foundational markup language for creating web pages. Developed in the early 1990s, it remains essential for nearly every website on the internet. Unlike earlier eras when only professional developers wrote HTML, it’s now accessible to anyone willing to learn the basics. HTML works through a system of…
Installing a Paravirtualized DomU on Xen Xen remains a solid hypervisor choice for specific workloads, though KVM dominates most Linux distributions today. This guide covers installing a paravirtualized DomU on Xen using modern tooling and Rocky Linux 9, which requires specific kernel parameters during installation. Why Paravirtualization Matters Paravirtualized guests communicate directly with the hypervisor…
USB Standards Overview USB standards continue evolving with significant speed improvements across generations. Linux support is comprehensive across all modern standards. USB 2.0 Speed: 480 Mbps (≤60 MB/s theoretical) Status: Legacy but ubiquitous. Nearly all systems retain USB 2.0 ports for backward compatibility Linux support: Built-in via ehci-hcd driver in all modern kernels USB 3.0…
Download the kernel source Grab a release from kernel.org. Recent stable versions (6.x and later) are recommended for production systems: wget https://www.kernel.org/pub/linux/kernel/v6.x/linux-6.12.tar.gz tar xf linux-6.12.tar.gz cd linux-6.12/ If wget isn’t available, use curl: curl -O https://www.kernel.org/pub/linux/kernel/v6.x/linux-6.12.tar.gz Verify the tarball’s integrity using the checksums and signatures published on kernel.org: wget https://www.kernel.org/pub/linux/kernel/v6.x/linux-6.12.tar.gz.asc gpg –verify linux-6.12.tar.gz.asc linux-6.12.tar.gz This…
Data Visualization for Better Business Decisions Data visualization transforms raw numbers into actionable insights. When you’re drowning in metrics—sales figures, customer demographics, geographic data, transaction history—visualization is how you extract signal from noise. The human brain processes visual information faster and more intuitively than spreadsheet rows, which is why charts and dashboards have become essential…
How the Linux Kernel Collects Task Stats Data The Linux kernel provides the taskstats API to monitor detailed per-task statistics, including I/O wait time, CPU scheduling delays, and memory reclamation waits. Understanding how these metrics are collected at the kernel level gives you insight into process behavior and helps diagnose performance issues. The Challenge with…
Picking Your First Programming Language Choosing your first programming language matters, but it’s not the career-defining decision some make it out to be. What matters more is that you pick something reasonable and start building. That said, some choices will save you months of frustration. Know What You’re Optimizing For Before you evaluate languages, answer…
vimtutor: The Built-in Vim Tutorial vimtutor is the most effective way to learn Vim. Unlike web tutorials, it’s an interactive lesson built directly into Vim that teaches through practice rather than passive reading. You run it straight from the terminal, which means no context switching and immediate feedback on everything you type. Running vimtutor From…
Spring Shell is a framework for building command-line interfaces (CLIs) in Java applications. It provides a structured way to define commands, handle user input, and create interactive shell applications backed by the Spring ecosystem. Requirements Spring Shell 3.2+ supports Java 17+ and Spring Boot 3.2+. For legacy applications still on older stacks, Spring Shell 2.x…
Background: Lock Contention in QEMU/KVM QEMU/KVM uses global locks to synchronize threads, which is necessary for correctness but causes performance problems at scale. When multiple I/O requests and vCPU threads contend for the same lock, you get lock contention that manifests as scheduling jitter, reduced system scalability, and degraded I/O performance. The dataplane feature addresses…
Filter Salutation in Microsoft Dynamics CRM Filtering dependent fields based on parent field values is a common requirement in Dynamics CRM. This guide covers implementing conditional filtering so the salutation dropdown only shows values relevant to the selected gender. Prerequisites Access to a Dynamics CRM environment (2016 and later) with customization rights Basic understanding of…
Filtering Dependent Lookup Fields in Dynamics 365 Filtering a dependent lookup field based on another lookup field’s value is a common requirement in Dynamics 365. A practical example: in a Lead entity with Branch and Sub Branch fields, you want Sub Branch options to display only those records matching the selected Branch. This is handled…
CFS Scheduler Timeslice Measurement in Linux Kernels CFS (Completely Fair Scheduling) is the default process scheduler in modern Linux kernels. Understanding actual timeslice allocation—how long a process runs before being context-switched out—is essential for performance debugging, verifying fairness assumptions, and identifying scheduling anomalies. The challenge is that built-in /proc interfaces and ps commands show scheduling…
Converting a managed solution to unmanaged in on-premise Dynamics CRM requires direct database modification. This is necessary when you need to customize a third-party solution or export it for deployment, but the publisher hasn’t provided an unmanaged version. Prerequisites Full backup of your CRM database (non-negotiable — this modifies system tables) SQL Server Management Studio…
Understanding CFS Scheduling Parameters The Completely Fair Scheduler (CFS) is the default process scheduling algorithm in modern Linux kernels. It allocates CPU time proportionally to each process based on their priority, ensuring fairness across workloads. Three key parameters control how timeslices are calculated and when preemption occurs: sched_min_granularity_ns, sched_latency_ns, and sched_wakeup_granularity_ns. How the Scheduling Period…
REST API Integration with ASP.NET MVC Consuming REST APIs from an ASP.NET MVC backend requires coordinated frontend-backend architecture. This guide covers the essential patterns for CRUD operations with proper error handling and validation. Note on frameworks: AngularJS reached end-of-life in 2022. This post documents the legacy approach for maintenance scenarios only. New projects should use…
Migration Threads in the Linux Kernel In computer systems, resources must be balanced across available hardware to maximize performance. The Linux kernel runs migration threads as per-CPU daemons to handle this work. These threads manage task migration between CPUs, CPU hotplug operations, and stop-machine synchronization. You can observe migration threads on any modern system: $…
CPU affinity binds a process or thread to specific CPU cores, reducing cache misses, improving performance isolation, and managing NUMA locality. The sched_setaffinity() system call is the primary mechanism in Linux. Understanding how it works at the kernel level clarifies scheduler internals and helps you use it effectively. System Call Entry Point The sched_setaffinity() syscall…