In a multiprogramming and time-sharing environment, several users share the system simultaneously.

This situation can result in various security problems.

a. What are two such problems?

b. Can we ensure the same degree of security in a time-shared machine as we have in a dedicated machine? Explain your answer.

a. Stealing or copying one's programs or data; using system resources (CPU, memory, disk space, peripherals) without proper accounting.

b. Probably not, since any protection scheme devised by humans can inevitably be broken by a human and the more difficult the scheme, the more difficult it is to feel confident of its correct execution.