Brandon Li has developed a browser-based semiconductor device simulator called SemiSim. It allows users to visualize the internal workings of transistors and diodes by simulating the drift and diffusion of charge carriers under varying biases and doping profiles. Users can define the device structure, adjust parameters like voltage and doping concentrations, and observe the resulting electric field, potential, and carrier densities in real-time. The simulator aims to be an educational tool, providing an interactive way to understand fundamental semiconductor physics concepts without requiring complex software or specialized knowledge.
The blog post "Three Fundamental Flaws of SIMD ISAs" argues that current SIMD instruction sets are hampered by three key weaknesses. First, they lack flexibility due to fixed vector widths and data types, making them inefficient for operations on diverse or irregular data structures. Second, horizontal operations within SIMD registers are cumbersome and often require inefficient shuffling, impacting performance in scenarios like finding the maximum value within a vector. Finally, the rigid instruction formats limit expressiveness, making it difficult to perform complex operations without breaking down computations into numerous simpler instructions, increasing complexity and reducing overall performance. These flaws necessitate revisiting SIMD architectures to explore more flexible and expressive alternatives better suited for the increasingly diverse computational landscapes of today.
Hacker News users generally agreed with the author's premise that SIMD instruction sets are complex and difficult to use effectively. Several commenters pointed out that auto-vectorization has improved but is still far from perfect, often requiring code restructuring to work well. The lack of portability between different SIMD architectures was also highlighted as a major drawback, echoing the article's point about fragmentation. One compelling comment suggested that GPUs address some of these flaws by offering a higher-level programming model, but introduce new complexities around memory management. Another pointed out the niche but useful application of SIMD in cryptography, countering the author's implicit focus on graphics/multimedia. Some users debated the significance of the flaws, suggesting that while real, they are inherent trade-offs for the performance gains SIMD offers and that future hardware/software advancements might mitigate them.
MIT's 6.5950 Secure Hardware Design is a free and open-source course exploring the landscape of hardware security. It covers various attack models, including side-channel attacks, fault injection, and reverse engineering, while also delving into defensive countermeasures. The course features lecture videos, slides, labs with open-source tools, and assessments, providing a comprehensive learning experience for understanding and mitigating hardware vulnerabilities. It aims to equip students with the skills to analyze and secure hardware designs against sophisticated attacks.
HN commenters generally expressed enthusiasm for MIT offering this open-source hardware security course. Several appreciated the focus on practical attack and defense techniques, noting its relevance in an increasingly security-conscious world. Some users highlighted the course's use of open-source tools and FPGA boards, making it accessible for self-learning and experimentation. A few commenters with backgrounds in hardware security pointed out the course's comprehensiveness, covering topics like side-channel attacks, fault injection, and reverse engineering. There was also discussion about the increasing demand for hardware security expertise and the value of such a free resource.
This blog post chronicles a personal project to build a functioning 8-bit computer from scratch, entirely with discrete logic gates. Rather than using a pre-designed CPU, the author meticulously designs and implements each component, including the ALU, registers, RAM, and control unit. The project uses simple breadboards and readily available 74LS series chips to build the hardware, and a custom assembly language and assembler are developed for programming. The post details the design process, challenges faced, and ultimately demonstrates the computer running simple programs, highlighting the fundamental principles of computer architecture through a hands-on approach.
HN commenters discuss the educational value and enjoyment of Ben Eater's 8-bit computer project. Several praise the clear explanations and well-structured approach, making complex concepts accessible. Some share their own experiences building the computer, highlighting the satisfaction of seeing it work and the deeper understanding of computer architecture it provides. Others discuss potential expansions and modifications, like adding a hard drive or exploring different instruction sets. A few commenters mention alternative or similar projects, such as Nand2Tetris and building a CPU in Logisim. There's a general consensus that the project is a valuable learning experience for anyone interested in computer hardware.
Byran created a fully open-source laptop called the "Novena," featuring a Field-Programmable Gate Array (FPGA) for maximum hardware customization and a transparent design philosophy. He documented the entire process, from schematic design and PCB layout to firmware development and case construction, making all resources publicly available. The project aims to empower users to understand and modify every aspect of their laptop hardware and software, offering a unique alternative to closed-source commercial devices.
Commenters on Hacker News largely praised the project's ambition and documentation. Several expressed admiration for the creator's dedication to open-source hardware and the educational value of the project. Some questioned the practicality and performance compared to commercially available laptops, while others focused on the impressive feat of creating a laptop from individual components. A few comments delved into specific technical aspects, like the choice of FPGA and the potential for future improvements, such as incorporating a RISC-V processor. There was also discussion around the definition of "from scratch," acknowledging that some pre-built components were necessarily used.
This blog post details a simple 16-bit CPU design implemented in Logisim, a free and open-source educational tool. The author breaks down the CPU's architecture into manageable components, explaining the function of each part, including the Arithmetic Logic Unit (ALU), registers, memory, instruction set, and control unit. The post covers the design process from initial concept to a functional CPU capable of running basic programs, providing a practical introduction to fundamental computer architecture concepts. It emphasizes a hands-on approach, encouraging readers to experiment with the provided Logisim files and modify the design themselves.
HN commenters largely praised the Simple CPU Design project for its clarity, accessibility, and educational value. Several pointed out its usefulness for beginners looking to understand computer architecture fundamentals, with some even suggesting its use as a teaching tool. A few commenters discussed the limitations of the simplified design and potential extensions, like adding interrupts or expanding the instruction set. Others shared their own experiences with similar projects or learning resources, further emphasizing the importance of hands-on learning in this field. The project's open-source nature and use of Verilog also received positive mentions.
Researchers have developed a new transistor that could significantly improve edge computing by enabling more efficient hardware implementations of fuzzy logic. This "ferroelectric FinFET" transistor can be reconfigured to perform various fuzzy logic operations, eliminating the need for complex digital circuits typically required. This simplification leads to smaller, faster, and more energy-efficient fuzzy logic hardware, ideal for edge devices with limited resources. The adaptable nature of the transistor allows it to handle the uncertainties and imprecise information common in real-world applications, making it well-suited for tasks like sensor processing, decision-making, and control systems in areas such as robotics and the Internet of Things.
Hacker News commenters expressed skepticism about the practicality of the reconfigurable fuzzy logic transistor. Several questioned the claimed benefits, particularly regarding power efficiency. One commenter pointed out that fuzzy logic usually requires more transistors than traditional logic, potentially negating any power savings. Others doubted the applicability of fuzzy logic to edge computing tasks in the first place, citing the prevalence of well-established and efficient algorithms for those applications. Some expressed interest in the technology, but emphasized the need for more concrete results beyond simulations. The overall sentiment was cautious optimism tempered by a demand for further evidence to support the claims.
Summary of Comments ( 19 )
https://news.ycombinator.com/item?id=43942279
HN users discussed the practicality and educational value of Brandon Li's semiconductor simulator. Several praised its clear visualizations and interactive nature, finding it a helpful tool for understanding complex concepts like doping and carrier movement. Some questioned the simulator's accuracy and simplification of real-world semiconductor physics, suggesting it might be misleading for beginners. Others offered suggestions for improvement, including adding more features like different semiconductor materials and more complex device structures. The discussion also touched upon the challenges of balancing simplicity and accuracy in educational tools, with some arguing for a more rigorous approach. A few commenters shared their own experiences learning about semiconductors and recommended additional resources.
The Hacker News post titled "Brandon's Semiconductor Simulator" has generated a number of comments discussing various aspects of the simulator and related topics.
Several commenters praise the simulator's educational value. One user highlights its usefulness in visualizing complex concepts like parasitic capacitance and resistance, making it a valuable tool for those learning about semiconductor physics. Another commenter appreciates the interactive nature of the simulator, contrasting it with traditional SPICE simulations which they find less intuitive for understanding device behavior. The accessibility of the simulator, being browser-based and free to use, is also commended.
Some commenters discuss the technical aspects of the simulator. One user asks about the numerical methods employed, specifically inquiring about the use of Gummel iteration. Another user questions the simulator's handling of more complex devices like MOSFETs, wondering if it simplifies certain aspects of their behavior. There's also a discussion about the potential limitations of the simulator, acknowledging that while useful for educational purposes, it might not be suitable for professional circuit design due to its simplified models.
A few comments delve into related topics, such as the history of semiconductor device simulation and the challenges of accurately modeling semiconductor behavior. One commenter mentions older simulators like PISCES, highlighting the advancements made in computational power and accessibility over time. Another comment thread explores the trade-offs between accuracy and computational cost in semiconductor simulation, noting the complexity of capturing all the physical phenomena involved.
Finally, there are some comments focusing on the user interface and user experience of the simulator. Suggestions are made for improvements, like adding more detailed documentation and allowing users to save and share their simulations. One commenter also expresses a desire for more advanced features, such as the ability to simulate circuits with multiple devices.
Overall, the comments on the Hacker News post reflect a positive reception of the semiconductor simulator, emphasizing its educational value and accessibility. The discussion also touches upon technical aspects of the simulator, related topics in semiconductor simulation, and potential improvements to the user experience.