The blog post argues against the widespread adoption of capability-based programming languages, despite acknowledging their security benefits. The author contends that capabilities, while effective at controlling access to objects, introduce significant complexity in reasoning about program behavior and resource management. This complexity arises from the need to track and distribute capabilities carefully, leading to challenges in areas like error handling, memory management, and debugging. Ultimately, the author believes that the added complexity outweighs the security advantages in most common programming scenarios, making capability languages less practical than alternative security approaches.
This 1972 paper by Parnas compares two system decomposition strategies: one based on flowcharts and step-wise refinement, and another based on information hiding. Parnas argues that decomposing a system into modules based on hiding design decisions behind interfaces leads to more stable and flexible systems. He demonstrates this by comparing two proposed modularizations of a KWIC (Key Word in Context) indexing system. The information hiding approach results in modules that are less interconnected and therefore less affected by changes in implementation details or requirements. This approach prioritizes minimizing inter-module communication and dependencies, making the resulting system easier to modify and maintain in the long run.
HN commenters discuss Parnas's modularity paper, largely agreeing with its core principles. Several highlight the enduring relevance of information hiding and minimizing inter-module dependencies to reduce complexity and facilitate change. Some commenters share anecdotes about encountering poorly designed systems violating these principles, reinforcing the paper's importance. The concept of "secrets" as the basis of modularity resonated, with discussions about how it applies to various levels of software design, from low-level functions to larger architectural components. A few commenters also touch upon the balance between pure theory and practical application, acknowledging the complexities of real-world software development.
Jazco's post argues that Bluesky's "lossy" timelines, where some posts aren't delivered to all followers, are actually beneficial. Instead of striving for perfect delivery like traditional social media, Bluesky embraces the imperfection. This lossiness, according to Jazco, creates a more relaxed posting environment, reduces the pressure for virality, and encourages genuine interaction. It fosters a feeling of casual conversation rather than a performance, making the platform feel more human and less like a broadcast. This approach prioritizes the experience of connection over complete information dissemination.
HN users discussed the tradeoffs of Bluesky's sometimes-lossy timeline, with many agreeing that occasional missed posts are acceptable for a more performant, decentralized system. Some compared it favorably to email, which also isn't perfectly reliable but remains useful. Others pointed out that perceived reliability in centralized systems is often an illusion, as data loss can still occur. Several commenters suggested technical improvements or alternative approaches like local-first software or better synchronization mechanisms, while others focused on the philosophical implications of accepting imperfection in technology. A few highlighted the importance of clear communication about potential data loss to manage user expectations. There's also a thread discussing the differences between "lossy" and "eventually consistent," with users arguing about the appropriate terminology for Bluesky's behavior.
The blog post "Common mistakes in architecture diagrams (2020)" identifies several pitfalls that make diagrams ineffective. These include using inconsistent notation and terminology, lacking clarity on the intended audience and purpose, including excessive detail that obscures the key message, neglecting important elements, and poor visual layout. The post emphasizes the importance of using the right level of abstraction for the intended audience, focusing on the key message the diagram needs to convey, and employing clear, consistent visuals. It advocates for treating diagrams as living documents that evolve with the architecture, and suggests focusing on the "why" behind architectural decisions to create more insightful and valuable diagrams.
HN commenters largely agreed with the author's points on diagram clarity, with several sharing their own experiences and preferences. Some emphasized the importance of context and audience when choosing a diagram style, noting that highly detailed diagrams can be overwhelming for non-technical stakeholders. Others pointed out the value of iterative diagramming and feedback, suggesting sketching on a whiteboard first to get early input. A few commenters offered additional tips like using consistent notation, avoiding unnecessary jargon, and ensuring diagrams are easily searchable and accessible. There was some discussion on specific tools, with Excalidraw and PlantUML mentioned as popular choices. Finally, several people highlighted the importance of diagrams not just for communication, but also for facilitating thinking and problem-solving.
The Canva outage highlighted the challenges of scaling a popular service during peak demand. The surge in holiday season traffic overwhelmed Canva's systems, leading to widespread disruptions and emphasizing the difficulty of accurately predicting and preparing for such spikes. While Canva quickly implemented mitigation strategies and restored service, the incident underscored the importance of robust infrastructure, resilient architecture, and effective communication during outages, especially for services heavily relied upon by businesses and individuals. The event serves as another reminder of the constant balancing act between managing explosive growth and maintaining reliable service.
Several commenters on Hacker News discussed the Canva outage, focusing on the complexities of distributed systems. Some highlighted the challenges of debugging such systems, particularly when saturation and cascading failures are involved. The discussion touched upon the difficulty of predicting and mitigating these types of outages, even with robust testing. Some questioned Canva's architectural choices, suggesting potential improvements like rate limiting and circuit breakers, while others emphasized the inherent unpredictability of large-scale systems and the inevitability of occasional failures. There was also debate about the trade-offs between performance and resilience, and the difficulty of achieving both simultaneously. A few users shared their personal experiences with similar outages in other systems, reinforcing the widespread nature of these challenges.
Summary of Comments ( 55 )
https://news.ycombinator.com/item?id=43956095
Hacker News users discuss capability-based security, focusing on its practical limitations. Several commenters point to the difficulty of auditing capabilities and the lack of tooling compared to established access control methods like ACLs. The complexity of reasoning about capability propagation and revocation in large systems is also highlighted, contrasting the relative simplicity of ACLs. Some users question the performance implications, specifically regarding the overhead of capability checks. While acknowledging the theoretical benefits of capability security, the prevailing sentiment centers around the perceived impracticality for widespread adoption given current tooling and understanding. Several commenters also suggest that the cognitive overhead required to develop and maintain capability-secure systems might be too high for most developers. The lack of real-world, large-scale success stories using capabilities contributes to the skepticism.
The Hacker News post "Why not object capability languages?" with ID 43956095 has generated several comments discussing various aspects of capability-based security and its practical implications.
Several commenters delve into the complexities of implementing and adopting capability-based systems. One commenter highlights the difficulty of retrofitting capabilities into existing systems, suggesting that a complete rewrite is often necessary. They also point out the learning curve associated with capability-based programming, which can be steep for developers accustomed to traditional access control models. Another commenter emphasizes the scarcity of tools and libraries designed for capability systems, making development more challenging compared to established environments. The challenges of debugging capability-based systems are also mentioned, with a commenter noting the difficulty of tracing authority and identifying the source of errors.
The performance implications of capabilities are also a topic of discussion. One commenter mentions the potential overhead associated with capability checks, especially in performance-sensitive applications. Another commenter counters this argument by suggesting that the fine-grained control offered by capabilities can actually improve performance by reducing unnecessary access checks. However, they acknowledge the need for careful design and implementation to avoid performance bottlenecks.
Some commenters explore alternative approaches to security, such as using type systems for access control. One commenter argues that type systems can provide similar benefits to capabilities while being more familiar to developers. Others point out that type systems and capability-based security are not mutually exclusive and can be used in conjunction to enhance overall system security.
The discussion also touches upon the social and economic factors influencing the adoption of capability systems. One commenter suggests that the lack of widespread adoption stems from the network effects of existing systems, making it difficult for new paradigms to gain traction. They also note the inertia within organizations, where switching to a new security model can be disruptive and costly. The discussion also delves into the challenges of explaining the benefits of capabilities to non-technical stakeholders, highlighting the need for better communication and advocacy within the broader software community.
Several commenters express support for the potential of capability-based security, while acknowledging the practical hurdles that need to be overcome. They emphasize the need for more research, development, and education to make capability systems more accessible and practical for mainstream adoption. One commenter suggests that focusing on specific use cases and demonstrating tangible benefits could help drive adoption.
Finally, there's a brief discussion about specific capability-based languages and systems, with mentions of Pony and Joe-E as examples of promising approaches. These comments provide pointers for readers interested in exploring existing implementations of capability-based security.