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Questions and Answers
What is one fundamental task assigned to the File Manager?
What is one fundamental task assigned to the File Manager?
What is a potential disadvantage of contiguous file storage?
What is a potential disadvantage of contiguous file storage?
How does the file manager enhance security during file access?
How does the file manager enhance security during file access?
What does the policy implementation in file management refer to?
What does the policy implementation in file management refer to?
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Why are extensions important in file-naming conventions?
Why are extensions important in file-naming conventions?
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Which is a key difference between fixed-length and variable-length record formats?
Which is a key difference between fixed-length and variable-length record formats?
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What is a role of data compression in file storage?
What is a role of data compression in file storage?
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Flexibility of access to information includes which aspect?
Flexibility of access to information includes which aspect?
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What is the role of the index file in a file management system?
What is the role of the index file in a file management system?
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Which programming technique is used at the level implementation of a file management system?
Which programming technique is used at the level implementation of a file management system?
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What does the logical file system transform to a byte address?
What does the logical file system transform to a byte address?
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Which module checks if a requested file exists?
Which module checks if a requested file exists?
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What is a disadvantage of file sharing?
What is a disadvantage of file sharing?
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Which statement is true about the access control matrix?
Which statement is true about the access control matrix?
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How does the access control list differ from the access control matrix?
How does the access control list differ from the access control matrix?
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Which module checks if the storage device exists?
Which module checks if the storage device exists?
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What is the primary disadvantage of a lockword in file protection?
What is the primary disadvantage of a lockword in file protection?
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What kind of compression replaces repeated characters with a code?
What kind of compression replaces repeated characters with a code?
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Which file manager responsibility involves executing user commands?
Which file manager responsibility involves executing user commands?
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What is one of the distinguishing features of a capability list?
What is one of the distinguishing features of a capability list?
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Under which category do individuals with unrestricted access to all files fall?
Under which category do individuals with unrestricted access to all files fall?
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Which file organization scheme is characterized by taking a given number of characters from a previous entry?
Which file organization scheme is characterized by taking a given number of characters from a previous entry?
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In file access control, what does the OWNER have control over?
In file access control, what does the OWNER have control over?
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Which organization is responsible for ISO standards that apply to video and music compression?
Which organization is responsible for ISO standards that apply to video and music compression?
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Study Notes
File Management System
- The file management system is composed of a hierarchy of six levels: index, directory, logical file system, file organization, device interface, and access control verification module.
Levels in a File Management System
- The highest module passes information to lower modules, which are further subdivided into more specific tasks.
- The logical file system transforms record numbers to byte addresses.
- Verification occurs at every level, including directory level, access control verification, logical file system, and device interface module.
Access Control Verification Module
- File sharing has advantages (save space, synchronized updates, resource efficiency) and disadvantages (need to protect file integrity).
- There are five possible file actions: READ, WRITE, EXECUTE, DELETE, and combination.
- Four methods of access control are: Access Control Matrix, Access Control Lists, Capability Lists, and Lockwords.
Access Control Matrix
- Advantages: easy to implement, works well in systems with few files and users.
- Disadvantages: matrix size increases with files and users, wasted space due to null entries.
Access Control Lists
- Modification of access control matrix technique.
- Contains user names granted file access, with denied access grouped under “WORLD”.
The File Manager
- The file manager is software that manages file access responsibilities, including creating, deleting, modifying, and controlling files.
- It supports libraries of programs, online users, spooling operations, interactive computing, and collaborates with the device manager.
Responsibilities of the File Manager
- The file manager has four tasks: file storage tracking, policy implementation, file allocation, and file deallocation.
- Policy determines file storage location, system and user access, and uses device-independent commands.
File Protection
- Factors affecting file protection: flexibility of access to information, and subsequent protection.
- Protection methods: account numbers, passwords, lockwords, and categorizing users into SYSTEM, OWNER, GROUP, and WORLD.
Data Compression
- Data compression is a technique used to save space in files.
- Compression schemes include text compression and other schemes for large files, video, music, and photographs.
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Description
This quiz covers the concepts of file management systems, including levels, implementation, and modular programming techniques, as discussed in the Understanding Operating Systems, Fifth Edition textbook.
