Chapter 11, Problem 38E

Explanation of Solution

File protection mechanism:

• It is a primary operation need to protect the file from multiple users who access the system, because there might be illegal users who can also access the file.
• The protection mechanism of the file differs based upon the type of operating system.
  • The file protection mechanism in operating system is used to check whether the valid user is accessing the particular file.
  • File protection mechanism is also used to identify the user who uses the file for which purpose.
• For example, in UNIX environment, the file protection is represented in the table format and consists of three rows and three columns as follows:

Operation	Owner	Group	World
Read	Yes	Yes	Yes
Write/Delete	Yes	Yes	No
Execute	No	No	No

Explanation:

From the above table,

• Each cell in the table represents the Boolean values.
• The file protection settings are divided into three types:
  • Owner
  • Group
  • World
• Owner:
  • The owner is the person who creates the file and has full rights on the file...