How does file protection based on access permissions work? Base your answer on various types of users of a file and the types of operations they can perform. How many permission bits are needed to implement this scheme? Why?
What will be an ideal response?
File protection based on access permissions is provided by a mechanism that prevents users from accessing each others’ files when they are not logged on as the owner of a file. As the owner of a file, you can attach certain access rights to the file that dictate who can and cannot access it for various types of file operations. This scheme is based on the types of users, the types of access permissions, and the types of operations allowed on a file under LINUX. Without such a protection scheme, users can access each others’ files because the LINUX file system structure (see Figure 7.2) has a single root from which hang all the files in the system.
The number of protection bits needed to implement this scheme is equal to the product of the number of types of users and the number of types of operations. In LINUX, the number of types of users is 3 (owner, group, others) and the number is types of operations is also 3 (read, write, execute). Thus the number of bits needed to implement this protection scheme is 3x3 = 9.
You might also like to view...
Drop Shadow is one of the most commonly used Photoshop effects.
Answer the following statement true (T) or false (F)
A(n) ________ is a predefined formula that performs calculations by using specific values in a particular order or structure
Fill in the blank(s) with correct word
When a project reaches the delivery stage, it is said to be ____________________.
Fill in the blank(s) with the appropriate word(s).
The conversion control sequence ____ would cause an integer number to both display its sign and be left-justified in a field width of 10 spaces.
A. %-+10d B. %-10d C. %+10d D. %*10d