In the context of my Master of Engineering thesis, I developed a sophisticated extension to EGOS-2000, a minimalistic operating system crafted by Cornell University’s Ph.D. candidate, Yunhao Zhang. This operating system, constructed from only 2000 lines of code, is designed specifically for deployment on FPGA development boards. Despite its minimalistic approach, EGOS-2000 is an entirely functional OS that incorporates all fundamental functionalities of an operating system, encompassing but not restricted to file systems, preemptive process switching, and user management.
Nonetheless, a significant limitation emerges in the deliberate effort to
conserve the number of code lines, manifesting as a lack of support for a
broad spectrum of standard C libraries. Instead, the system is equipped
with a limited array of proprietary functions offered as system calls,
thereby substantially narrowing the scope of the project and imposing
challenges in writing or porting applications to the OS. My thesis aimed
to mitigate this issue by integrating select C standard libraries into the
OS, namely math.h, stdlib.h,
stdio.h, ctype.h, and string.h.
This incorporation allowed the operating system to support these
fundamental library functions, thereby simplifying the process for
developers to design applications for EGOS-2000.
I undertook several experimental solutions, including attempts to link compilers’ C library implementations to user applications. However, such solutions proved unfeasible due to the constraints of FPGA development boards, particularly the restricted RAM. This signaled that many contemporary solutions to this problem would be incompatible. I thus devised a solution that categorizes the entire C standard library into two distinct divisions: OS-dependent and OS-independent. The former includes functions such as file operations that necessitate OS support, while the latter contains functions like mathematical operations that operate independently of OS support.
Moreover, I executed a recompilation of the kernel with C library functions, leveraging the kernel’s significantly more liberal allowance on code size. By offering an interface that connects to these functions, user applications are empowered to utilize the C standard library as they would on any contemporary operating system. The OS-dependent operations were restructured to enable communication with server processes and satisfy pertinent requests.
This project was conducted under the esteemed supervision of Dr. Robert van Renesse, Professor and Director of Graduate Studies at Cornell’s Computer Science department, and received high commendation, being awarded an A+ grade.