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?
1. One user can read the private data of another user - privacy.
2. One user can corrupt the private data of another user - integrity.
3. One user can prevent another user from getting anything done - denail of service.
b) Can we ensure the same degree of security in a time-shared machine as we have in a dedicated machine? Explain your answer.
There are two answers, either one correct.
a. Yes - if we can ensure that the operating system prevents any sharing of data between users, either for reading or writing, and fairly shares the computer, then we can achieve the same level of security.
b. No - we can never be sure that our software doesn't have bugs, so we can never be sure that we prevent all sharing of data and fairly allocate computer resources.