This chapter discusses a programmer’s view of files and the file system. It describes fundamental file organizations, directory structures, operations on files and directories, and file sharing semantics, which specify the manner in which results of file manipulations performed by concurrent processes are visible to one another. Issues that compromise reliability of a file system are discussed. Fault tolerance using atomic actions and recovery using backups are described. | Chapter 13 File Systems Copyright © 2008 Operating Systems, by Dhananjay Dhamdhere Introduction Overview of File Processing Files and File Operations Fundamental File Organizations and Access Methods Directories Mounting of File Systems File Protection Allocation of Disk Space Interface Between File System and IOCS 13. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Operating Systems, by Dhananjay Dhamdhere Introduction (continued) File Processing File Sharing Semantics File System Reliability Journaling File Systems Virtual File System Case Studies of File Systems Performance of File Systems 13. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Operating Systems, by Dhananjay Dhamdhere Overview of File Processing 13. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Operating Systems, by Dhananjay Dhamdhere File System and the IOCS File system views a file as a collection of data that is owned by a user, shared by a set of . | Chapter 13 File Systems Copyright © 2008 Operating Systems, by Dhananjay Dhamdhere Introduction Overview of File Processing Files and File Operations Fundamental File Organizations and Access Methods Directories Mounting of File Systems File Protection Allocation of Disk Space Interface Between File System and IOCS 13. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Operating Systems, by Dhananjay Dhamdhere Introduction (continued) File Processing File Sharing Semantics File System Reliability Journaling File Systems Virtual File System Case Studies of File Systems Performance of File Systems 13. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Operating Systems, by Dhananjay Dhamdhere Overview of File Processing 13. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Operating Systems, by Dhananjay Dhamdhere File System and the IOCS File system views a file as a collection of data that is owned by a user, shared by a set of authorized users, and reliably stored over an extended period IOCS views it as a repository of data that is accessed speedily and stored on I/O device that is used efficiently Two kinds of data: file data and control data 13. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Operating Systems, by Dhananjay Dhamdhere File Processing in a Program At programming language level: File: object with attributes describing organization of its data and the method of accessing the data 13. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Operating Systems, by Dhananjay Dhamdhere File types can be grouped into two classes: Structured files: Collection of records Record: collection of fields Field: contains a single data item Each record is assumed to contain a unique key field Byte stream files: “Flat” A file has attributes, stored in its directory entry Files and File Operations 13. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Operating Systems, by
