The early computers of the late 1940s had no operating system. Human operators scheduled jobs for execution and supervised the use of the computer's resources. Because these early computers were very expensive, the main purpose of an operating system in these early days was to make the hardware as efficient as possible. Now, computer hardware is relatively cheap by comparison with the cost of the personnel required to operate it, so the purpose of the operating system has evolved to encompass the task of making the user as efficient as possible. a) Differentiate between NTFS and FAT in term of security. b) Discuss TWO (2) main categories of processor registers. c) Differentiate between multiprocessor and multicore system. d) Describe on why DMA access to main memory is given higher priority than processor access to main memory.