Question 25

In a file system directory, all file names within a given directory must be strictly unique. In an unsorted linear list implementation, searching for a name requires traversing the list node by node.

• Creation of a new file (Option A): To maintain unique naming, the file system must first verify that no existing file already has the new file's name. Because the target name does not exist, the search cannot find a match and must scan the entire list to the very end before adding the new node. (Full scan required)
• Deletion of an existing file (Option B): The scan terminates as soon as the target file node is located and unlinked. If the file is near the beginning, only a partial scan is performed. (Full scan not necessarily required)
• Renaming of an existing file (Option C): Renaming requires verifying that the target new name does not already exist in the directory. Checking for non-existence of the new name requires scanning all nodes to the end. (Full scan required)
• Opening of an existing file (Option D): The search terminates as soon as the existing file is found. (Full scan not necessarily required)

Therefore, operations A and C necessarily require a full scan of the directory.