Security in Computing 5th Edition by Shari Lawrence Pfleeger, Charles P Pfleeger, Jonathan Margulies

Exercise 7

The discussion of base/bounds registers implies that program code is execute-only and that data areas are read-write-only. Is this ever not the case? Explain your answer.

Step 1 of 2

Read or write access rights to user’s block in the same location:

The base/bounds register the program code with only executable or read-write access enables the operation to be performed as a complete program or nothing.

For example, if the user wants to perform the write operation on a specific location of the user block while that location is already performing reading operation in the same block, then that case is not possible.

The adjacent location or the same location within the user block will have to undergo the same instruction.

Hence, the case is not possible when the program code is executed, and the data areas have the access rights of read and write only.