Fitting a Forth in 512 bytes (2021)

The article discusses the challenge of bootstrapping a practical system from a minimal 512-byte seed, specifically focusing on fitting a Forth programming language into this constraint. The author reflects on the complexities of circular dependencies in software, such as needing a running kernel to compile a kernel. Inspired by a thought experiment, the author aims to create a functional system starting from a bare minimum of software. The solution identified is a compact version of Forth, which is a stack-based programming language. The development process involved optimizing the code to fit within the 512-byte limit while maintaining functionality. The article details the structure and execution strategy of the Forth implementation, including the use of threaded code and a dictionary for word management. The author also discusses compression techniques to save space, ultimately achieving a working Forth interpreter that fits within the constraints. The project highlights the ingenuity required in low-level programming and the potential for creating functional systems from minimal resources.

- The article explores bootstrapping a system from a 512-byte seed using Forth.

- Forth is a stack-based language that allows for runtime extensibility.

- The author optimized the Forth implementation to fit within the 512-byte limit.

- Techniques such as threaded code and dictionary management are employed in the implementation.

- Compression methods were used to save space while maintaining functionality.