FS Implementation 2.In-memory information:For both FS management and performence improvement via caching Data are loaded at mount time and discarded at dismount Structures include: Sppen (file name directory structure directory structure file-control block user space kemnel memory secondary storage (a) index 口口口 read (index 口口口 directory blocks per-process system-wide open file table open file table file-control block user space kernel memory secondary storage (b) 口”48+4在4色主月Q0. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FS Implementation 2. In-memory information: For both FS management and performence improvement via caching ▶ Data are loaded at mount time and discarded at dismount ▶ Structures include: ▶ in-memory mount table; ▶ in-memory directory-structure cache ▶ system-wide open-file table; ▶ per-process open-file table user space open (file name) kernel memory directory structure secondary storage file-control block directory structure (a) user space read (index) kernel memory per-process open file table system-wide open file table secondary storage file-control block directory blocks index (b)