Chapter 10: File-System Interface
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ch10 File System Interface(1).pdf 操作系统（本）2024-12-12 第 7-8 节
File-System 负责管理外存
File Concept
A file is a sequence of bytes stored on some device
Access Methods（文件的访问方法）
Sequential Access （顺序存取）从头到尾一个个找
Direct Access （直接存取），先定位到一个地方，再对这个地方进程操作
Indexed sequential-acess
Directory Structure（目录结构）
Directory Structure
A collection of nodes containing information about all files
Disk Structure
Disk can be subdivided into partitions（分区）
Entity containing file system known as a volume
Each volume containing file system also tracks that file system’s info in device directory or volume table of contents
Single-Level Directory（单级目录）
A single directory for all users
Two-Level Directory（二级目录）
Separate directory for each user
进一步的，我们可以得到 Tree-Structured Directories（树型目录）
Acyclic-Graph Directories 无环图结构目录
Have shared subdirectories and files -> Two different names (aliasing)
File System Mounting
A file system must be mounted before it can be accessed