The Common Object File Format (COFF) is a file format used for object code, executables, and shared libraries in various operating systems, particularly Unix-like systems and Windows. It serves as a container for machine code, debugging information, relocation data, and symbol tables. COFF files are typically generated by compilers and assemblers as intermediate files during the software build process. These object files are then linked together by a linker to create a final executable or library. The format allows for modular compilation and linking, where different parts of a program can be compiled separately and then combined. COFF supports various architectures and data types, making it a versatile format for different platforms. It's a crucial component in the toolchain for software development, enabling efficient compilation and linking of large and complex programs. The format's structure facilitates debugging and allows for dynamic linking, where libraries are loaded at runtime. COFF has evolved over time, with variations and extensions implemented by different operating systems and compilers.