提纲 File-System Structure FS Implementation Directory Implementation Allocation Methods(分配方法) Free-Space Management Efficiency(空间)and Performance(时间) Recovery Log Structured File Systems 小结 4口”484在4色，主月QC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 提纲 File-System Structure FS Implementation Directory Implementation Allocation Methods (分配方法) Free-Space Management Efficiency (空间) and Performance (时间) Recovery Log Structured File Systems 小结
File-System Structure File structure Logical storage unit Collection of related informationapplication programs ↓ FS resides on secondary storage File name logical file system (disks) ↓ FS organization Logical block address file-organization module How FS should look to the user ↓ Physical block address How to map the logical FS onto basic file system the physical secondary-storage ↓ Issue commands to l/O to retrieve physical block devices l/O control FS organized into layers Hardware-specific instructions devices Figure:Layered File System 口”48+4在4色”主)QC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . File-System Structure ▶ File structure ▶ Logical storage unit ▶ Collection of related information ▶ FS resides on secondary storage (disks) ▶ FS organization ▶ How FS should look to the user ▶ How to map the logical FS onto the physical secondary-storage devices ▶ FS organized into layers application programs File name logical file system Logical block address file-organization module Physical block address basic file system Issue commands to I/O to retrieve physical block I/O control Hardware-specific instructions devices Figure: Layered File System
Outline FS Implementation 4口”4614在4生：主QC
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FS Implementation Structures and operations used to implement file system operation,OS-&FS-dependment 1.On-disk structures 2.In-memory structures 4口”4814在，4色，主)QC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FS Implementation ▶ Structures and operations used to implement file system operation, OS- & FS-dependment 1. On-disk structures 2. In-memory structures
FS Implementation 1.On-disk structures 1.1 Boot control block To boot an OS from the partition(volume) If empty,no OS is contained on the partition 1.2 Volume control block 1.3 Directory structure 1.4 Per-file FCB file permissions file dates(create,access,write) file owner,group,ACL file size file data blocks or pointers to file data blocks Figure:A typical file control block 4口”484在4色，主月QC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FS Implementation 1. On-disk structures 1.1 Boot control block ▶ To boot an OS from the partition (volume) ▶ If empty, no OS is contained on the partition 1.2 Volume control block 1.3 Directory structure 1.4 Per-file FCB file permissions file dates (create, access, write) file owner, group, ACL file size file data blocks or pointers to file data blocks Figure: A typical file control block