The document discusses file system implementation and structure. It covers topics like directory implementation using linear lists and hash tables, different allocation methods like contiguous, linked and indexed allocation, free space management using bit vectors and linked lists, improving efficiency through caching, and recovery methods like consistency checking and log-structured file systems. It also provides an overview of the Sun Network File System (NFS) including its architecture, mount protocol, and remote operations.

3. Layered File System

4. A Typical File Control Block

6. In-Memory File System Structures

8. Schematic View of Virtual File System

12. Contiguous Allocation of Disk Space

16. Linked Allocation

17. File-Allocation Table

19. Example of Indexed Allocation

23. Indexed Allocation – Mapping (Cont.)  outer-index index table file

24. Combined Scheme: UNIX (4K bytes per block)

28. Linked Free Space List on Disk

30. Various Disk-Caching Locations

32. I/O Without a Unified Buffer Cache

34. I/O Using a Unified Buffer Cache

40. Three Independent File Systems

41. Mounting in NFS Mounts Cascading mounts

45. Schematic View of NFS Architecture