File System Implementation
- File systems are typically layered, to provide useful abstractions at various levels.
- Figure 16.11 diagrams typical file system data structures:
- Process Descriptor contains an open file pointer array, used to point a processesí open files to entries in the open file table.
- The open file table is a system-wide OS-managed table of entries for all opened files. It typically contains:
- Current file position
- File status info (R/W, locks, file type, etc.)
- Pointer to the file descriptor/device driver/pipe data structure
- The file descriptor table is an in-memory copy of disk-resident file descriptors