Technology Tales

If you ever need to install Linux kernel headers on an openSUSE instance in order to install VirtualBox Guest Additions, the following command should be executed in order to do the needful:

sudo zypper in kernel-source

Using Docker macvlan networks

Using Docker's macvlan network type allows containers to connect directly to a local network by creating virtual interfaces, but this approach requires careful configuration to avoid IP address conflicts. To prevent conflicts, a reserved subnet range must be designated, ensuring Docker assigns addresses within that range while excluding them from standard DHCP allocation. Additionally, communication between the host and containers on a macvlan network is limited, necessitating the creation of a secondary macvlan interface on the host, which is then configured with a reserved IP address and linked to the network via routing rules. This setup enables the host to interact with containers but requires manual configuration that is not persistent across reboots, depending on the host's operating system.

RFC Editor serves as the central repository for the Request for Comments (RFC) series, a collection of technical documents that establish the foundational standards and protocols underpinning the internet. These documents, produced by organisations such as the Internet Engineering Task Force, the Internet Research Task Force and independent contributors, outline protocols, architectural principles, operational practices and experimental research, forming a sequential and permanent record of internet development that dates back to 1969. The RFC Editor organisation oversees the editing, publication and archiving of these documents, which cover a wide range of technologies including TCP, IP, HTTP, SMTP, DNS and TLS. The site provides access to browse, search and download RFCs, along with information on their standards status, errata and updates, ensuring their availability to the public and supporting the internet's open and interoperable nature. The term "Request for Comments" originated from the informal exchange of ideas among early researchers, which later evolved into the formal documentation process that continues to shape internet standards today.

Snapcraft

Developed by Canonical, this is a packaging and build tool that enables developers to create self-contained software packages for Linux distributions. The tool automates the transformation of source code into distributable packages by collecting application files and dependencies, compiling the application, bundling everything together and facilitating publication to a centralised store.

Developers define their build requirements through a configuration file that specifies application details, version information, dependencies, build instructions and runtime environment settings. When executed, the tool downloads necessary build dependencies, compiles the project, bundles required libraries and produces a final package that can be uploaded for distribution.

These packages run consistently across multiple Linux distributions because they include all necessary libraries rather than relying on system-installed components. The resulting packages operate within a confined environment with permission controls, update automatically and can be published through multiple release channels including stable, candidate, beta and edge versions. This approach to packaging differs from traditional methods by emphasising reproducible builds and dependency isolation, making it particularly useful for distributing command-line tools, developer utilities and desktop applications without maintaining separate packages for each distribution.

Show the slide number and total number of slides on every PowerPoint slide

The process of displaying slide numbers and total slide counts in PowerPoint presentations requires manual configuration through the Slide Master view, where a text box is inserted and formatted to include both the current slide number and a manually entered total. This method does not automatically update if additional slides are added later, necessitating manual adjustments. Users can provide feedback to suggest future enhancements that might automate this functionality, though current tools rely on user-initiated steps to achieve the desired presentation formatting.

Yawcam is webcam software for Windows that has been in use for over two decades, offering features such as video streaming, motion detection, image overlays and support for multiple cameras. The latest version, Yawcam Ai, focuses on video surveillance with enhanced object detection capabilities. The classic version remains widely used for its simplicity and inclusion of standard functions like built-in web servers, FTP uploads and time-lapse movies.

Haiku

This open source operating system focuses on personal computing through a unified approach where a single development team creates all components from the kernel to desktop applications. Built with a custom kernel designed for responsiveness and featuring full threading for efficient multi-processor performance, it offers a database-like file system with indexed metadata support and a rich object-oriented API. The project represents a realisation of concepts from the Be Operating System, aiming to provide simple and efficient personal computing through seamless integration of various open source projects into a cohesive whole. Development occurs through a global community of volunteer contributors supported by a non-profit organisation, with the system remaining freely available whilst maintaining consistency that benefits both everyday users and developers.

Close the Tools pane in Acrobat Reader DC

Adobe Acrobat Reader includes a preference setting that allows users to control the visibility of the All tools pane, ensuring its state—whether collapsed or expanded—remains consistent across sessions. By adjusting the 'Remember last state of All tools pane when opening documents' option in the Documents preferences, the application retains the user's preferred layout.

Jukka Svahn

This collection of plugins for the Textpattern content management system provides a range of functionalities including Bit.ly link shortening, password management, comment handling, spam prevention, feed customisation and administrative tools such as IP-based access control and caching management. Several plugins were updated in 2013 with version increments, reflecting ongoing development and maintenance efforts. The plugins are designed to enhance user interaction, streamline content creation and improve site administration, with features like revision control, advanced sitemap generation and simplified interface elements. The collection is maintained by Jukka Svahn, with copyright held from 2007 to 2026.

Optimizing the use of the Google Font API

Google engineers recommend several practices for optimising font loading performance through their Font API, including combining multiple font requests into a single query using the pipe character, placing font links in the base HTML rather than using import directives in external CSS files, positioning font requests early in the page after the opening head tag, and requesting only fonts that are actually used. Performance analysis of 28 popular sites using the Font API revealed that on fast connections around 100 megabits per second, fonts added only 37 milliseconds to page load time on average, whilst medium speed connections at 3 megabits per second saw a barely significant increase of 34 milliseconds. However, slower connections at 384 kilobits per second experienced a noticeable impact of approximately 1 second, with the delay correlating directly to the compressed size of the font files. The findings suggest that high-bandwidth users can enjoy web fonts with minimal performance impact since font requests load in parallel with other page elements, whilst slower connections bear the cost of additional data transfer, though the team is working on further compression methods to improve this situation.