1. What is the difference of OS in terms of user view and system view?

ANSWER:
Users view-the user view of the computer varies by the interface being used. Most computer users sit in front of a PC, consisting of a monitor, keyboard, mouse and system unit. Such a system is designed for one user to monopolize its resources, to maximize the work that the user is performing. In this case,the operating system is designed mostly for ease of use, with some attention paid to performance, and none paid to resource utilization.

Some users sit at a terminal connected to a mainframe or minicomputer. Other users are accessing the same computer through other terminals. These users share resources and may exchange information. The operating system is designed to maximize resource utilization.
Other users sit at workstations, connected to networks of other workstations and servers. These users have dedicated resources at their disposal, but they also share resources such as networking and servers.

Recently, many varieties of handheld computers have come into fashion. These devices are mostly standalone, used singly by individual users. Some are connected to networks, either directly by wire or through wireless modems. Due to power and interface limitations they perform relatively few remote operations. These operating systems are designed mostly for individual usability, but performance per amount of battery life is important as well.

System View-We can view an operating system as a resource allocator. A computer system has many resources - hardware and software - that may be required to solve a problem. The operating system acts as the manager of these resources.
An operating system can also be viewed as a control program that manages the execution of user programs to prevent errors and improper use of the computer. It is especially concerned with the operation and control of I/O devices.