Deleting structure.56
- 1. File Concept, File Management, File Attributes http://raj-os.blogspot.in/ 1
- 2. Recap In the last class, you have learnt • Single and two level directories • Tree-structured directories http://raj-os.blogspot.in/ 2
- 3. • HOME PREVIOUS TOPIC NEXT • PREVIOUS QUESTION PAPERS FOR OS • CPP TUTORIALS http://raj-os.blogspot.in/ 3
- 4. Objectives On completion of this period, you would be able to: • Understand how deletion of a directory from a tree structured directory is handled • Advantages and limitations of tree-structured directories • Understand acyclic-graph directory structure http://raj-os.blogspot.in/ 4
- 5. Deleting a Directory • Two cases arise • The directory to be deleted is empty • The directory to be deleted is non empty http://raj-os.blogspot.in/ 5
- 6. Deleting an Empty Directory • Delete its entry from its containing directory http://raj-os.blogspot.in/ 6
- 7. Deleting a Non Empty Directory Two ways to handle the situation 1. Do not delete unless the directory is empty 2. Request confirmation from the user whether the non empty directory is to be deleted along with the directory’s files and subdirectories http://raj-os.blogspot.in/ 7
- 8. The First Approach is used by MS-DOS • If a user wants to delete a non empty directory, he must first delete all the files in that directory • If there are any subdirectories, same procedure must be recursively applied • Involves a substantial amount of work http://raj-os.blogspot.in/ 8
- 9. The Second Approach is used by Unix • Provide an option to the user whether that directory’s files and subdirectories are also to be deleted • More convenient than the first approach, but more dangerous if command to delete is issued in error http://raj-os.blogspot.in/ 9
- 11. State whether the following are true or false http://raj-os.blogspot.in/ 11
- 12. State True or False In a tree structured directory a user can not create his own subdirectories False http://raj-os.blogspot.in/ 12
- 13. State True or False • Only a non empty directory can be removed False http://raj-os.blogspot.in/ 13
- 14. State True or False • An acyclic graph is a natural generalization of a tree- structured scheme True http://raj-os.blogspot.in/ 14
- 15. Other subject materials • Web designing • Micro processors • C++ tutorials • java home http://raj-os.blogspot.in/ 15