In recent years, within the era of the Software Defined Vehicle (SDV), the role of file systems has become increasingly vital. This trend is driven by the transformation in vehicular storage systems, notably the transition from NOR to NAND, as well as the evolution from bare-metal systems to POSIX-compliant OSs. These changes have underscored the need for file systems that facilitate rapid and efficient data access and prompt system boot-up. Furthermore, as autonomous vehicles become more mainstream, the importance of capturing and storing driving logs escalates. In such critical scenarios, sudden power losses, fragmentation, and device lifespan management are among the stringent requirements imposed on file systems. In this lecture, we will delve deeply into the pivotal significance of file systems in the SDV era.