The proc filesystem is a virtual filesystem in Linux that provides an interface to kernel data structures and system information. It differs from other filesystems in that it does not store data on disk, but rather presents a dynamic view of the system's current state and activities in a hierarchical structure that can be accessed and manipulated like other files. Unlike other filesystems, the proc filesystem is not used for permanent storage of data, but instead provides a convenient way for programs to access and modify system information in real time.