LWN's review explores Joplin, an open-source note-taking application that aims to be a robust Evernote alternative. It supports a variety of features, including Markdown editing, synchronization across devices using various services (Nextcloud, Dropbox, WebDAV, etc.), end-to-end encryption, and importing from Evernote. The review highlights Joplin's strengths, such as its offline functionality, extensive features, and active development, while also pointing out some UI/UX quirks and occasional performance issues. Overall, Joplin is presented as a compelling option for users seeking a powerful, privacy-respecting, and flexible note-taking solution.
A developer encountered a perplexing bug where multiple threads were simultaneously entering a supposedly protected critical section. The root cause was an unexpected optimization performed by the compiler. A loop containing a critical section, protected by EnterCriticalSection and LeaveCriticalSection, was optimized to move the EnterCriticalSection call outside the loop. Consequently, the lock was acquired only once, allowing all loop iterations for a given thread to proceed concurrently, violating the intended mutual exclusion. This highlights the subtle ways compiler optimizations can interact with threading primitives, leading to difficult-to-debug concurrency issues.
Hacker News users discussed potential causes for the described bug where a critical section seemed to allow multiple threads. Some pointed to subtle issues with the provided code example, suggesting the LeaveCriticalSection might be executed before the InitializeCriticalSection, due to compiler reordering or other unexpected behavior. Others speculated about memory corruption, particularly if the CRITICAL_SECTION structure was inadvertently shared or placed in writable shared memory. The possibility of the debugger misleading the developer due to its own synchronization mechanisms also arose. Several commenters emphasized the difficulty of diagnosing such race conditions and recommended using dedicated tooling like Application Verifier, while others suggested simpler alternatives for thread synchronization in such a straightforward scenario.
PG-Capture offers an efficient and reliable way to synchronize PostgreSQL data with search indexes like Algolia or Elasticsearch. By capturing changes directly from the PostgreSQL write-ahead log (WAL), it avoids the performance overhead of traditional methods like logical replication slots. This approach minimizes database load and ensures near real-time synchronization, making it ideal for applications requiring up-to-date search functionality. PG-Capture simplifies the process with a single, easy-to-configure binary and supports various output formats, including JSON and Protobuf, allowing flexible integration with different indexing platforms.
Hacker News users generally expressed interest in PG-Capture, praising its simplicity and potential usefulness. Some questioned the need for another Postgres change data capture (CDC) tool given existing options like Debezium and logical replication, but the author clarified that PG-Capture focuses specifically on syncing indexed data with search services, offering a more targeted solution. Concerns were raised about handling schema changes and the robustness of the single-threaded architecture, prompting the author to explain their mitigation strategies. Several commenters appreciated the project's MIT license and the provided Docker image for easy testing. Others suggested potential improvements like supporting other search backends and offering different output formats beyond JSON. Overall, the reception was positive, with many seeing PG-Capture as a valuable tool for specific use cases.
Imapsync is a command-line tool designed for synchronizing or migrating email accounts between IMAP servers. It supports a wide range of scenarios, including one-way and two-way synchronization, transferring emails between different providers, migrating to a new server, and creating backups. Imapsync offers features like folder filtering, bandwidth control, SSL/TLS encryption, and the ability to resume interrupted transfers. It prioritizes data safety and accuracy, employing techniques like dry runs to preview changes and MD5 checksum comparisons to verify message integrity. While primarily aimed at advanced users comfortable with command-line interfaces, its documentation provides detailed instructions and examples.
Hacker News users discuss imapsync's utility for migrating email, highlighting its speed and effectiveness, particularly with large mailboxes. Some users praise its ability to handle complex migrations across different providers, while others caution about potential issues like duplicate emails if not used carefully. Several commenters suggest alternative tools like OfflineIMAP, isync, and mbsync, comparing their features and ease of use to imapsync. A few users also share their experiences using imapsync for specific migration scenarios, offering practical tips and workarounds for common challenges.
Researchers have identified spontaneous, synchronized oscillations in the movement of dense human crowds, similar to those observed in flocks of birds or schools of fish. By analyzing high-resolution trajectory data from high-density crowd events, they discovered distinct collective oscillatory modes where individuals unconsciously coordinate their movements, swaying side-to-side or back-and-forth. These oscillations emerge at certain critical densities and appear to be driven by local interactions between individuals, enhancing crowd fluidity and facilitating navigation. This discovery sheds light on the fundamental principles governing human collective behavior and could contribute to safer and more efficient crowd management strategies.
Hacker News users discussed the study on crowd oscillations with a mix of skepticism and interest. Some questioned the novelty of the findings, pointing out that synchronized swaying in crowds is a well-known phenomenon, especially at concerts. Others expressed concern about the methodology, particularly the reliance on overhead video and potential inaccuracies in tracking individual movements. Several commenters suggested alternative explanations for the observed oscillations, such as subconscious mimicking of neighbors or reactions to external stimuli like music or announcements. There was also a thread discussing the potential applications of the research, including crowd management and understanding collective behavior in other contexts. A few users appreciated the visualization and analysis of the phenomenon, even if they weren't surprised by the underlying behavior.
Summary of Comments ( 23 )
https://news.ycombinator.com/item?id=43734732
Hacker News users discuss Joplin's strengths as a note-taking application, particularly its open-source nature, end-to-end encryption, Markdown support, and cross-platform availability. Several commenters appreciate its ability to handle code snippets effectively. Some compare it favorably to other note-taking apps like Obsidian, Standard Notes, and Evernote, highlighting its speed and offline functionality as advantages. Concerns mentioned include the interface being less polished than commercial alternatives and the reliance on Electron. One commenter raises a security concern related to the use of Electron, while another suggests alternative synchronization methods for improved privacy. A few users share their positive experiences with Joplin and its extensibility.
The Hacker News post "Taking Notes with Joplin" spawned a lively discussion with several compelling comments about the note-taking application. Many users shared their experiences and opinions on Joplin, comparing it to other popular alternatives and highlighting its strengths and weaknesses.
A recurring theme is Joplin's strong support for Markdown and its flexible synchronization capabilities. Several commenters praised its ability to sync with various cloud services like Nextcloud, Dropbox, and WebDAV, giving users control over their data. This is contrasted with proprietary solutions like Evernote, which lock users into their ecosystem. One user specifically mentions switching from Evernote due to privacy concerns and appreciating Joplin's open-source nature and end-to-end encryption.
The cross-platform availability of Joplin across Windows, macOS, Linux, Android, and iOS is also frequently mentioned as a significant advantage. Users appreciate having a consistent note-taking experience across their devices.
However, the discussion isn't without criticisms of Joplin. Some users find the user interface to be less polished than commercial alternatives, and the mobile experience is described as "functional but not great" by one commenter. Another user points out the lack of a WYSIWYG editor, which might deter some users. The learning curve associated with Markdown is also mentioned as a potential barrier to entry.
A few comments delve into specific features, such as the web clipper and the ability to attach files to notes. One user expresses their satisfaction with the web clipper, while another suggests improvements to the handling of PDF attachments.
The discussion also touches upon alternative note-taking applications like Standard Notes, Obsidian, and Zettlr, with users comparing their features and functionalities to Joplin. Some users recommend specific combinations of software, like using Joplin with Syncthing for synchronization.
Overall, the comments paint a picture of Joplin as a powerful and versatile, albeit slightly rough-around-the-edges, note-taking application. Its open-source nature, robust synchronization options, and cross-platform availability are highly praised, while its user interface and mobile experience are identified as areas for potential improvement. The discussion provides valuable insights for anyone considering Joplin as their note-taking solution.