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Add reCAPTCHA to a Form Without Trusting the Browser

A reCAPTCHA widget is only the browser half of the control. This implementation verifies each short-lived, single-use token on the server, checks the expected hostname, handles failures safely, and layers reCAPTCHA with ordinary anti-abuse controls.

ARM Registers Explained: AArch32 and AArch64

ARM does not have one universal set of “16 registers.” AArch32 exposes R0–R15, while AArch64 provides X0–X30 plus separate SP, PC behavior, status fields, vector registers, and system state. This reference connects the architecture to real function calls and debugging.

Skype on Ubuntu Is Retired: What to Use Now

Installing the old `skypeforlinux` package is no longer a working solution: Microsoft retired Skype on May 5, 2025. Ubuntu users should move to Teams on the web or its PWA, handle any remaining Skype data, and remove the unsupported client.

Explore a Running Linux Process Through /proc

Linux procfs exposes a live, file-like view of process state without creating ordinary files on disk. This lab starts a harmless C process, captures its PID, inspects the useful `/proc/PID` entries, and cleans up reliably.

How C Code Becomes a Running Linux Process

A single GCC command hides several distinct transformations, followed later by Linux process startup. Saving each intermediate file makes macros, assembly, ELF objects, linking, and dynamic loading much easier to reason about.

Raspberry Pi Serial Console with a USB-TTL Cable

A serial console lets you watch boot messages and log in when networking or video is unavailable. The connection is simple only after voltage, crossed TX/RX wiring, model differences, and console configuration are correct.

Build and Customize Yocto Image Recipes

A Yocto image recipe describes the root filesystem and image features you want; the selected machine and BSP layers provide the board-specific kernel, bootloader, and hardware configuration. This walkthrough turns that relationship into a repeatable build you can maintain.

Enable Moodle Self-Enrolment and Fix Access Errors

Moodle self-enrolment has two switches: the site plugin must be available, and an active Self enrolment method must exist in the course. Dates, keys, capacity, roles, and account state can still prevent enrolment.

Remove the Calendar Block from Moodle Pages

Removing a Calendar block changes one page layout; it does not erase Moodle calendar events. Identify whether you are editing Site home, your personal Dashboard, or the default Dashboard before making the change.

Assign a Teacher to a Moodle Course

In Moodle, Teacher is normally a course-scoped role. Enrol the account from the course Participants page, choose the least-privileged teaching role, and verify the resulting access before classes begin.

Submit a Website to Bing and Verify Indexing

Submitting a site is not a promise of rankings or even immediate indexing. It gives Bing reliable discovery signals and gives you the diagnostics needed to understand what happens next.

Debug C Programs with GDB on Ubuntu

A debugger becomes useful when a crash that looked random becomes one source line, one call path, and one impossible value. Follow a complete GDB investigation from failure to verified fix.

Install perf in Ubuntu Linux

Perf is a profiler tool for Linux 2.6+ based systems that abstracts away CPU hardware differences in … Read more

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