Snowdrop OS is a hobby operating system written entirely in assembly language for x86-64 processors. The project aims to be a minimal, educational platform showcasing fundamental OS concepts. Currently, it supports booting into 32-bit protected mode, basic memory management with paging, printing to the screen, and keyboard input. The author's goal is to progressively implement more advanced features like multitasking, a filesystem, and eventually user mode, while keeping the code clean and understandable.
Sebastian Mihai's blog post details his ambitious personal project: building an operating system from the ground up, named Snowdrop OS. He emphasizes that this is a learning exercise, focusing on understanding the fundamental principles of operating system design and low-level programming. The core of Snowdrop OS is written entirely in assembly language, targeting x86-64 architecture, reflecting his desire for deep control and intimate interaction with the hardware.
The blog post outlines the initial stages of development, starting with the bootloader, which is the very first piece of code executed upon system startup. Mihai explains his bootloader's function, which involves setting up the Global Descriptor Table (GDT) and Interrupt Descriptor Table (IDT), crucial components for protected mode operation and interrupt handling, respectively. He details the painstaking process of manually crafting these tables in assembly, highlighting the challenges and intricacies of working at such a low level. He further elaborates on the process of switching the processor from real mode to protected mode, a critical step in setting up a modern operating system environment. This includes setting up segmentation, a memory management scheme used by x86 processors.
Mihai then describes implementing a basic keyboard driver, enabling the operating system to receive input from the user. He meticulously explains the mechanism behind keyboard interrupts and how his code intercepts and processes these signals to display typed characters on the screen. This involves interfacing directly with the hardware and understanding the intricacies of scan codes generated by the keyboard.
The post showcases screenshots of Snowdrop OS in its nascent state, displaying characters typed on the keyboard. This visually demonstrates the functionality achieved thus far. While acknowledging the project's early stage, Mihai outlines his long-term vision for Snowdrop OS. He aspires to gradually add more features, including a more advanced memory manager, support for multiple processes, and eventually a file system. He envisions Snowdrop OS as a platform for continuous learning and exploration of operating system concepts. The blog post concludes with an invitation for others interested in similar endeavors to connect and share their experiences, fostering a sense of community among like-minded individuals. He provides a link to the project's GitHub repository, making the source code openly available for inspection and collaboration.
Summary of Comments ( 5 )
https://news.ycombinator.com/item?id=42814820
HN commenters express admiration for the author's dedication and technical achievement in creating an OS from scratch in assembly. Several discuss the challenges and steep learning curve involved in such a project, with some sharing their own experiences with OS development. Some question the practical applications of the OS, given its limited functionality, while others see value in it as a learning exercise. The use of assembly language is a significant point of discussion, with some praising the low-level control it provides and others suggesting higher-level languages would be more efficient for development. The minimalist nature of the OS and its focus on core functionalities are also highlighted. A few commenters offer suggestions for improvements, such as implementing a simple filesystem or exploring different architectures. Overall, the comments reflect a mix of appreciation for the technical feat, curiosity about its purpose, and discussion of the trade-offs involved in such a project.
The Hacker News post titled "Snowdrop OS – a homebrew operating system from scratch, in assembly language" generated several comments discussing various aspects of the project.
Many commenters expressed admiration for the author's dedication and the technical achievement of building an OS from scratch, particularly using assembly language. They acknowledged the significant effort and learning involved in such an undertaking. Some saw it as a valuable learning experience, even if the resulting OS isn't practically useful.
Several comments focused on the choice of assembly language. Some questioned its practicality for a larger project, citing the increased development time and complexity compared to higher-level languages. They discussed the trade-offs between performance and development speed, with some suggesting that C might be a more suitable choice for a project of this scale. However, others defended the use of assembly, emphasizing the low-level control and understanding it provides, which aligns with the author's stated learning goals.
There was a discussion about the educational value of such projects. Some commenters shared their own experiences with similar endeavors, highlighting the insights gained into computer architecture and operating system principles. They emphasized the importance of hands-on experience for deepening understanding.
A few commenters delved into technical details, discussing specific aspects of the OS's implementation, such as memory management, interrupt handling, and the choice of bootloader. They offered suggestions for improvements and pointed out potential issues.
Some comments touched upon the project's potential future development. While acknowledging the current limitations, some commenters expressed interest in seeing the project evolve and gain more features.
There was a brief discussion about the licensing of the code, with a suggestion to choose a license explicitly.
Overall, the comments reflect a positive reception to the project, with an appreciation for the effort involved and the educational value of building an OS from scratch. While some questioned the practical implications and the choice of assembly language, the general sentiment was one of encouragement and interest in the author's learning journey.