24 Questions
What is one fundamental task assigned to the File Manager?
Creating, deleting, and modifying files
What is a potential disadvantage of contiguous file storage?
Difficulty in modifying files
How does the file manager enhance security during file access?
Using account numbers, passwords, and lockwords
What does the policy implementation in file management refer to?
Determining where and how files are stored
Why are extensions important in file-naming conventions?
They indicate the type of data contained within a file
Which is a key difference between fixed-length and variable-length record formats?
Variable-length formats reduce storage overhead for smaller files
What is a role of data compression in file storage?
Increasing storage space efficiency
Flexibility of access to information includes which aspect?
Allowing users to browse public directories
What is the role of the index file in a file management system?
It searches for pointers to data blocks.
Which programming technique is used at the level implementation of a file management system?
Structured and modular programming
What does the logical file system transform to a byte address?
Record number
Which module checks if a requested file exists?
Directory level
What is a disadvantage of file sharing?
Need to protect file integrity
Which statement is true about the access control matrix?
It can lead to wasted space due to null entries.
How does the access control list differ from the access control matrix?
It contains user names granted file access.
Which module checks if the storage device exists?
Device interface module
What is the primary disadvantage of a lockword in file protection?
Cannot control the type of access
What kind of compression replaces repeated characters with a code?
Text compression
Which file manager responsibility involves executing user commands?
Controlling every file
What is one of the distinguishing features of a capability list?
It lists every user and files each has access to
Under which category do individuals with unrestricted access to all files fall?
SYSTEM
Which file organization scheme is characterized by taking a given number of characters from a previous entry?
Front-end compression
In file access control, what does the OWNER have control over?
Files created in their own account
Which organization is responsible for ISO standards that apply to video and music compression?
International Organization for Standardization
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.
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.
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