1. Blackcandy: Self hosted music streaming server
Total comment counts : 53
Summary
Summary of Black Candy:
Black Candy is a self-hosted music streaming server designed to serve as a personal music center. Here are the key points:
- Demo: Users can test a demo version online, though it lacks full administrative capabilities and uses music from Free Music Archive.
- Installation: It uses Docker for easy installation. Users can access it via localhost or the host IP on port 3000.
- Upgrades: Users must follow an upgrade guide when updating to major versions due to potential breaking changes. Upgrades involve pulling new Docker images and replacing containers.
- Mobile Apps: Available on various app stores with APK available for Android from GitHub.
- Configuration: Supports port mapping, media file mounting, and uses SQLite by default, with an option for PostgreSQL. Data persistence is managed by mounting specific directories.
- Performance: Can use Nginx for more efficient audio file delivery.
- Logging: Logs to STDOUT, with Docker providing options for log management.
- Development: An edge version exists for developers, based on the master branch, which might be unstable.
- Features: Integration with Discogs API for artist and album images.
Black Candy provides a comprehensive solution for personal music streaming with easy setup, maintenance, and scalability options.
Top 1 Comment Summary
The article discusses the author’s experience with self-hosting applications at home. They currently host Jellyfin, which helps in managing and enjoying physical media like VHS and DVDs digitally, and Home Assistant for home automation. The author mentions avoiding a high-cost subscription for home security by opting for a self-hosted solution, supporting the developer with a small monthly payment despite not being necessary for functionality. The author expresses a desire for an easier way to discover more self-hosting applications.
Top 2 Comment Summary
The article discusses the author’s experience with various music playing options over the past 15 years, concluding that they prefer managing playlists on their computer and manually transferring them to their phone’s local storage for the best overall music listening experience.
2. Seconds Since the Epoch
Total comment counts : 27
Summary
The article discusses common misconceptions about POSIX time, which is often mistakenly described as the number of seconds since the Unix epoch (January 1, 1970, at 00:00:00 UTC). Here are the key points:
Definition and Misconception: POSIX time isn’t strictly the count of seconds since the epoch due to the inclusion of leap seconds, which are added to keep Coordinated Universal Time (UTC) aligned with solar time. This results in a discrepancy between the actual number of seconds and what POSIX time represents.
Leap Seconds: To maintain the accuracy of UTC, leap seconds are occasionally added. This causes POSIX time to jump backwards or potentially forward, leading to complications in systems expecting a continuous increase in time values.
IEEE Standard: The IEEE 1003.1 standard defines POSIX time in a way that assumes every day has exactly 86,400 seconds, ignoring leap seconds for simplicity, which leads to a divergence from actual time.
Practical Implications: The standard admits that systems do not track leap seconds accurately, and it suggests that vendors and system administrators should ensure time accuracy “as closely as necessary” for their applications. However, this is challenging due to the unpredictability and rarity of leap seconds.
System Time Handling: For applications needing precise time calculations within a single system, using alternatives like
CLOCK_MONOTONICis recommended. For systems requiring time synchronization with others using POSIX time, considerations like time smearing might be necessary to handle the discrepancies caused by leap seconds.Future Concerns: The article notes that while time synchronization issues are generally overlooked, the rare occurrence of leap seconds can lead to significant software bugs or system failures, highlighting the need for better time management in distributed systems.
The discussion emphasizes the inherent complexities and potential pitfalls in using POSIX time, especially in applications requiring high precision and synchronization across different systems.
Top 1 Comment Summary
The article discusses a proposal to eliminate leap seconds from Coordinated Universal Time (UTC) by 2035. The author expresses disapproval of this plan, arguing that the essence of UTC is to maintain synchronization with mean solar time (MST) through adjustments like leap seconds. If the tracking of MST is no longer a priority, the author suggests switching entirely to International Atomic Time (TAI), rather than letting UTC drift away from MST, which would leave UTC in a confusing state with historical but now purposeless leap seconds.
Top 2 Comment Summary
“A Deepness in the Sky” by Vernor Vinge, published in 2000, features a unique timekeeping system used by the Traders. They measure time from the moment humans first stepped on the moon, but more precisely, their system starts from the zero-second of one of the earliest computer operating systems, roughly 15 million seconds after the moon landing. This method involves complex frame corrections and a continuous counter.
3. Reads Causing Writes in Postgres
Total comment counts : 8
Summary
The article discusses how to monitor SQL statements in PostgreSQL, focusing on the pg_stat_statements view which tracks statistics like shared_blks_dirtied and shared_blks_written. These statistics show how many blocks in the shared buffer cache are modified or written to disk by SQL queries, including seemingly read-only SELECT statements due to mechanisms like:
Setting Hint Bits: This mechanism helps track the state of transactions, marking rows as visible to all transactions once certain conditions are met.
Page Pruning: This involves removing old row versions no longer needed, which can also trigger writes.
The article explains:
MVCC (Multi-Version Concurrency Control): PostgreSQL uses this to manage concurrent access to data, allowing different clients to see different versions of the same row depending on their transaction isolation levels. This can lead to phenomena like non-repeatable reads.
Data Organization in Postgres:
- Data is stored in files divided into blocks or pages, each typically 8192 bytes.
- Pages contain heap tuples (row versions).
- The table’s data structure includes a main fork for data, a free space map, and a visibility map.
The explanation includes a simplified example of a books table to illustrate how data is physically stored and managed in PostgreSQL, emphasizing the concepts of pages, blocks, and tuples.
Top 1 Comment Summary
The article discusses the challenges of understanding and troubleshooting PostgreSQL (referred to as “postgres”) when issues arise. It suggests that typically, one only delves into the workings of such a complex database system when something malfunctions, leading to feelings of nervousness, panic, and often confusion due to its counterintuitive behaviors. This experience, the author implies, might be common when dealing with any large, complex system.
Top 2 Comment Summary
The article highlights that in PostgreSQL, the default setting for work_mem is 4MB. This means that if operations like ORDER BY generate large intermediate results, these results will spill over to disk due to insufficient memory allocation, potentially slowing down query performance.
4. Ugandan runner due to arrive in London after 516 days, 7,700 miles on the road
Total comment counts : 11
Summary
Deo Kato, a Ugandan athlete, completed a 7,730-mile run from Cape Town to London to raise awareness about racism and human migration. Despite facing significant challenges such as imprisonment, serious illness, navigating through war zones, and daily racism in Europe, his journey has renewed his faith in humanity. Notable experiences included running with a multilingual teenager in Botswana and children in Kenya. However, he also encountered severe racism in Croatia and logistical nightmares in Africa due to conflicts. Kato’s run was symbolic, starting from a monument commemorating the anti-apartheid struggle in South Africa, and aimed to challenge racist notions of belonging. He hopes his efforts contribute to a future free from racial discrimination, despite acknowledging the difficulties posed by policies like “fortress Europe.” His partner, Alice Light, described the journey as an emotional rollercoaster, with plans for rest rather than celebration after this monumental effort.
Top 1 Comment Summary
Deo Kato successfully completed an impressive run from Cape Town to London, arriving on Sunday. The article linked in the post discusses his journey but does not detail how he crossed from continental Europe to England.
Top 2 Comment Summary
The article describes the frustration of encountering police checks frequently, about four times a day, while traveling through Croatia, suggesting that this experience is so cumbersome that the author would prefer to fly to the next destination instead of continuing the journey by road.
5. Siyuan: Privacy-first, self-hosted personal knowledge management software
Total comment counts : 21
Summary
Summary of the Article on SiYuan:
SiYuan is described as a privacy-first, self-hosted, and fully open-source personal knowledge management software developed in TypeScript and Go. Here are the key points:
Features: Supports fine-grained block-level references, Markdown WYSIWYG editing, and most features are free for both personal and commercial use. Some advanced features require a paid membership.
Installation: Recommended to install via app markets on desktop and mobile for easy updates. For servers, Docker deployment is suggested with detailed instructions on setting user permissions via environment variables (PUID and PGID) to manage access rights properly.
Data Management: Data is stored in a workspace folder. While third-party synchronization is not supported to avoid data corruption, manual export/import for data synchronization is an option, and there is support for connecting to third-party cloud storage for members.
Open Source: Completely open-source with opportunities for contributions, with acknowledgments to other open-source projects and contributors.
Community and Updates: Users are encouraged to join the English Discussion Forum, check for updates through settings or official channels, and provide feedback. Insider previews are available before major updates.
Usage: Instructions on managing permissions, setting up with Docker, and handling data across devices are provided, emphasizing user control and privacy.
Development and Contribution: The development guide is referenced for those interested in contributing to the project.
Overall, SiYuan positions itself as a tool for those valuing privacy, ease of use, and community-driven development in personal knowledge management.
Top 1 Comment Summary
The article provides insights on effective knowledge management and productivity, especially for those comfortable with Unix systems:
Basic Tools: The author suggests using simple, directory-based structures, plaintext files, and markdown for organizing information, advocating for a “File over app” approach typical of Unix philosophy.
Categorization: Information should be sorted using universal concepts like locations, things, people, events, metrics, and how-tos, similar to the 5Ws (Who, What, When, Where, Why).
Unix Tools: Emphasis is placed on using Unix tools like command-line utilities,
makeorjustfiles,grep,git, andfzffor efficient file management and searching.Avoid Web Solutions: The author warns against using web-based solutions for knowledge management as they often lead to dealing with web-related issues rather than enhancing productivity.
Touchscreen Challenge: While recognizing the inconvenience of using touchscreens for these tasks, the suggestion is to adapt existing tools rather than seeking new solutions.
Future Tool Desire: The author expresses interest in a Unix tool capable of creating backlinks among text files, allowing for interconnected notes by scanning for references within the file system.
Top 2 Comment Summary
The article discusses a user’s experience with a software that is similar to Obsidian, an open-source alternative. Here are the key points:
- Usage: The user has been using this software on their home server for a couple of years.
- Comparison to Obsidian: It’s described as a less polished version or “knock-off” of Obsidian.
- Features and Limitations: While it offers many of Obsidian’s features, it lacks in documentation and is somewhat unreliable (janky).
- Open-Source: The software is open-source, which the user appreciates.
- Company Information: The company behind the software is not well-known, identified only as Chinese with little information available.
- Reasons for Use: The user prefers this software because it can be self-hosted, includes most features of Obsidian, and crucially, allows access via web browsers from anywhere, a feature Obsidian does not provide.
6. I thought I found a bug
Total comment counts : 5
Summary
The article discusses a bug encountered while improving a DOS emulator, specifically with how COMMAND.COM handles file operations. The issue was related to the file I/O operations in C, where:
Initial Problem: When COMMAND.COM attempted to write specific data to a file, it resulted in unexpected output due to its handling of potential Ctrl-Z characters at the end of files.
Debugging: Using a debugger, the author identified issues with how the C runtime libraries (Open Watcom, Microsoft Visual C++, IBM C/C++) managed file writes, particularly with the sequence of read and write operations.
Behavioral Inconsistencies: Different compilers exhibited different behaviors when writing data. For instance, some wrote partial data or set error flags in non-intuitive ways, with errors like EPUTANDGET in IBM’s runtime.
Historical Context: The behavior stems from early C implementations where file modes were strictly for reading, writing, or appending, without an update mode that allowed mixed operations. This led to current standards requiring explicit flushing or repositioning when switching between reading and writing.
Standards Evolution: Over time, C standards have evolved to clarify that switching from output to input or vice versa without proper file positioning or flushing operations can lead to unpredictable results, although the core issue has remained essentially unchanged since the 1970s.
Conclusion: The complexity and historical baggage of C’s file I/O operations mean that developers must be cautious with file handling, especially when mixing read and write operations in update mode. The article highlights the need for understanding these nuances to avoid subtle bugs in file operations.
Top 1 Comment Summary
The article discusses the author’s discovery of an old document, the usr/group Standard, which they mention they possess in a digital format from an early DOS hard drive image. This document was from before the author switched to Linux in 1991. They express an intention to share this document online. Additionally, the author includes an output of a directory listing command (ls -altr) showing files like NOTES, LIB, APP, and C, which were last modified in April 1990, suggesting these files are from the same era as the mentioned standard.
Top 2 Comment Summary
The article discusses issues with stdio implementations where reading and writing operations cannot be freely mixed due to the use of a single buffer for both operations. Here are the key points:
Single Buffer Issue: Many stdio implementations use one buffer for both reading and writing. Switching between these operations requires clearing or resetting the buffer because the buffer might contain outdated or irrelevant data.
Functions to Reset Buffer: Functions like
fflush(),fseek(),rewind(), andfsetpos()are used to clear the buffer, making it safe to switch from reading to writing or vice versa.Lack of Operation Indicators: There’s typically no indicator in the
struct FILEto show whether the last operation was a read or write, which complicates automatic management of buffer states.Potential Solutions:
- Dual Buffers: An alternative would be to use separate buffers for reading and writing, but this wasn’t initially implemented.
- Documentation Over Fix: The problem was likely documented instead of fixed, possibly due to the complexity of retrofitting such changes into existing systems.
The article suggests that the initial implementation did not account for easy switching between read and write modes, and rather than redesigning the system with dual buffers or automatic flushing, maintainers chose to document the limitation.
7. Differential Growth Addon for Blender
Total comment counts : 9
Summary
The article discusses the fascination with organic shapes and patterns in nature, which have inspired human art and design throughout history. The author introduces a new tool named Differential Growth Addon for Blender, a 3D creation software. This addon, which is open-source and free, aims to contribute to the generative art community by allowing users to create organic patterns. The author encourages users to download the latest release from GitHub, engage with the community, ask questions, and share their creations. The tone is enthusiastic and community-oriented, emphasizing enjoyment and sharing within the artistic community.
Top 1 Comment Summary
The article discusses the author’s journey with Blender, a free 3D modeling software. Initially, the author humorously compares the time spent on video games to learning Blender, despite their initial lack of skill. Over time, they’ve enjoyed creating 3D models, some of which were used in games. The author highlights that with Blender, even those with limited skills can produce high-quality renders, emphasizing the software’s accessibility and ease of use.
Top 2 Comment Summary
The article mentions a free add-on for Blender called “Differential Growth” created by Alex Martinelli. This add-on uses Blender’s Geometry Nodes to simulate differential growth in 3D modeling. The link provided directs to a post on Blendernation discussing this tool.
8. Show HN: A singing synthesizer for the browser with automatic 3-part harmony
Total comment counts : 16
Summary
error
Top 1 Comment Summary
The article discusses a music synthesis project where:
- Source code is available on GitHub.
- Technology includes an AudioWorklet node with custom DSP (Digital Signal Processing) implemented using Rust and WebAssembly. Graphics are handled by the Canvas API.
- Voice Leading is managed algorithmically through a state machine with integrated heuristics.
- DSP Algorithm is based on a physical model of the human voice, similar to but advanced from the model used in Pink Trombone. This model is part of a small Rust crate named ‘voxbox’, which focuses on singing synthesizers.
Top 2 Comment Summary
The article mentions that the author has enjoyed Google’s Blob Opera, which is an interactive online experiment where users can create music through playful interaction with animated blobs representing different opera voices. The link provided directs to this Google Arts & Culture project.
9. A Minecraft server written in COBOL
Total comment counts : 21
Summary
Summary of the Article:
The article discusses “CobolCraft,” a unique project where a Minecraft server has been developed using COBOL, a language typically used for business applications rather than game development or low-level programming. Here are the key points:
Purpose and Development: The project was initiated to explore COBOL, despite the developer having no prior experience with the language. It supports Minecraft version 1.21.4 and focuses on basic server functionalities rather than complex block interactions.
Technical Details:
- The server runs on Linux using GnuCOBOL, with Docker suggested for cross-platform deployment.
- It uses TCP sockets managed by a custom library (CBL_GC_SOCKET) for network communication.
- Data handling involves decoding network captures from an official Minecraft server, and JSON parsing for server data extracted from the official server’s .jar file.
Deployment: Instructions are provided for setting up and running the server, including how to make it accessible beyond localhost.
Challenges and Learning: The developer highlights the challenges of using COBOL for such a project, emphasizing the educational aspect of the endeavor.
Legal and Licensing: The project is under the MIT License, except for the included third-party library which uses LGPL v3. It explicitly states no affiliation or endorsement by Mojang, the creators of Minecraft.
Documentation: References are provided for further learning about COBOL and the Minecraft protocol.
This project stands out for its unusual choice of language for a game server, showcasing the developer’s curiosity and commitment to learning through practical application.
Top 1 Comment Summary
The article discusses the author’s curiosity about COBOL, a programming language surrounded by rumors and stigma. Motivated to explore COBOL despite having no previous experience with it, the author embarked on a project to learn more about the language firsthand. The hope is expressed that the author will share insights from this experience, particularly regarding the challenges and perceptions of COBOL encountered during the project.
Top 2 Comment Summary
The article describes a high school graduation project where the author created a COBOL system to automate soccer betting odds. Despite COBOL being outdated, the school was still using it, making the project somewhat anachronistic yet enjoyable for the author, who found a unique charm in working with such an old programming language.
10. VPR: Nordic’s First RISC-V Processor
Total comment counts : 5
Summary
The article discusses Nordic Semiconductor’s introduction of their first RISC-V processor named VPR, which is part of their new nRF54H and nRF54L lines of System on Chips (SoCs). Here are the key points:
VPR Overview: VPR is an RV32E processor, using 32-bit registers but with only 16 registers as per the embedded specification, and it supports multiplication, division, and compressed instructions for better code density. It operates in machine mode only.
Integration in SoCs:
- The nRF54L includes a single VPR processor called FLPR for fast lightweight peripheral processing.
- The nRF54H20 features both FLPR and another VPR called PPR (Peripheral Processor) for handling peripherals at low power, alongside dual Arm Cortex-M33 processors.
Configuration and Operation: VPR processors need to be set up by the controlling application processor, which involves setting the program counter and starting the processor via specific registers.
Development and Testing:
- The article mentions using Zephyr RTOS for development, where hardware and peripherals are described using devicetree.
- For testing, a “hello_world” application is built for both the application processor and the PPR, demonstrating multi-target building capabilities.
Tools and Configuration:
- Tools from the Zephyr SDK are used to inspect and disassemble the built images.
- Configuration for the PPR involves enabling specific memory regions and defining device compatibility in the system.
This introduction of VPR by Nordic Semiconductor is significant for developers and companies interested in RISC-V, particularly in applications requiring low power consumption and efficient peripheral management.
Top 1 Comment Summary
The article discusses the author’s interest in the nRF54L15 chip, which has been recalled, delaying its mass availability. The author is exploring this chip as a potential upgrade from the nRF52 for a project that requires streaming data from a 1kHz sampling ADC over BLE. The need arises for either an efficient DMA engine capable of triggering without CPU interrupts or a dual-core processor. The author is also seeking community feedback on using DMA with nRF52 and esp32-h2 chips to determine if it’s worth the investment of time and effort.
Top 2 Comment Summary
The article discusses different types of cores in microcontroller technology:
Dual M33s: Likely referring to two ARM Cortex-M33 cores, which are known for their performance and security features.
VPR (Versatile Processing Resource): This includes:
- PPR (Peripheral Processing Resource): A low-power RISC-V RV32E core operating at 16 MHz, designed specifically for handling external I/O operations.
- FLPR (Flexible Low Power Resource): Another RISC-V RV32E core but running at a higher speed of 320 MHz, intended for software-defined peripherals.
The author expresses curiosity about the performance capabilities of the FLPR, particularly in terms of how fast it can toggle GPIO (General Purpose Input/Output) pins to generate a square wave, and whether this performance could compete with the PIO (Programmable I/O) capabilities of the RP2040 and RP2040/2350 microcontrollers.