State the required answer precisely and then provide proper explanation. It is not enough to provide one- word or one-line answers.
Some early computers protected the operating system by placing it in a memory partition that could not be modified by either a user job or the operating system itself (for example, by placing it in read-only memory).
Describe difficulties that you think could arise with such a scheme. Remember that an operating system must maintain a large number of data structures relating to processes, files, etc.