CS323 COMPUTER ARCHITECTURE CASE STUDY 2

CS323 COMPUTER ARCHITECTURE
CASE STUDY 2

1.0.) In a multiprogramming and time-sharing environment, several users share the system simultaneously.
This siguation can result in various security problems.

   a.) Stealing or copying a user's files.
   b.) Writing over another program's (belonging to another user or to the OS) area in memory.
   c.) Using system resources (CPU, disk space) without proper accounting.
   d.) Causing the printer to mix output by sending data while some other user's file is printing.

1.1.) There is an advantage and disadvantage in a multiprogramming and time sharing environment.

   ADVANTAGES
   a.) Multiprocessor systems can save money, by sharing power supplies.
   b.)  Can execute programs more quickly and can have increased reliability.

   DISADVANTAGES
   a.) Multiprocessor systems are more complex in both hardware and software.
   b.) Additional CPU cycles are required to manage the cooperation, so per-CPU efficiency goes down.

1.2) Can we ensure the same degree of secutiry in a time-shared machine as we have in a dedicated machine?

   a.) Probably not, since any protection scheme devised by a human can also be broken --
       and the more complex the scheme is, the more difficult it is to be confident
       of its correct implementation.