Revolutionizing Unix: The 4.3BSD Fast File System

This article delves into the revolutionary improvements of the Fast File System (FFS) introduced in the 4.3BSD Unix operating system of 1984. Addressing limitations of the traditional Unix filesystem in file size, I/O speed, and file count, FFS significantly enhanced performance and stability through optimized file layout, increased block size, exploitation of disk physical characteristics, and introduction of new file types and system calls. FFS design principles, such as co-locating metadata and data, and optimizing I/O based on disk rotation speed, profoundly impacted subsequent filesystem designs and laid the groundwork for efficient modern operating systems.