现代操作系统全套配套课件4eTanenbaumPPT及教学资料Chapter04-FileSystems.ppt

Implementing Files I-nodes Figure 4-13. An example i-node. Tanenbaum Bo, Modern Operating Systems:4th ed., (c) 2013 Prentice-Hall, Inc. All rights reserved. Implementing Directories (1) Figure 4-14. (a) A simple directory containing fixed-size entries with the disk addresses and attributes in the directory entry. (b) A directory in which each entry just refers to an i-node. Tanenbaum Bo, Modern Operating Systems:4th ed., (c) 2013 Prentice-Hall, Inc. All rights reserved. Implementing Directories (2) Figure 4-15. Tw o ways of handling long file names in a directory. (a) In-line. (b) In a heap. Tanenbaum Bo, Modern Operating Systems:4th ed., (c) 2013 Prentice-Hall, Inc. All rights reserved. Shared Files (1) Figure 4-16. File system containing a shared file. Tanenbaum Bo, Modern Operating Systems:4th ed., (c) 2013 Prentice-Hall, Inc. All rights reserved. Shared Files (2) Figure 4-17. (a) Situation prior to linking. (b) After the link is created. (c) After the original owner removes the file. Tanenbaum Bo, Modern Operating Systems:4th ed., (c) 2013 Prentice-Hall, Inc. All rights reserved. Journaling File Systems Steps to remove a file in UNIX: Remove file from its directory. Release i-node to the pool of free i-nodes. Return all disk blocks to pool of free disk blocks. Tanenbaum Bo, Modern Operating Systems:4th ed., (c) 2013 Prentice-Hall, Inc. All rights reserved. Virtual File Systems (1) Figure 4-18. Position of the virtual file system. Tanenbaum Bo, Modern Operating Systems:4th ed., (c) 2013 Prentice-Hall, Inc. All rights reserved. Virtual File Systems (2) Figure 4-19. A simplified view of the data structures and code used by the VFS and concrete file system to do a read. Tanenbaum Bo, Modern Operating Systems:4th ed., (c) 2013 Prentice-Hall, Inc. All rights reserved. Disk Space Management (1) Figure 4-20. Percentage of files smaller than a given size (in bytes). Tanenbaum Bo, Modern Operating Systems:4th ed., (c) 2013 Prentice-Hall, I