The user view of the computer varies by the interface being used. Most computer users sit in front of 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 (or play) that the user is perfoming. 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. Perfomance is important to the user, but it does not matter if most of the system is sitting idle, waiting for the slow I/O speed of the user.
Some users sit at a terminal connected to mainframe or minicomputer. others 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- to assure that all avilable cpu time,memory, and I/O are used efficienty, and that no individuls user takes more than her fair share.
Other users sit at workstations, connected to networks of other workstaiton and servers. These users have dedicated resources at their disposal, but they also share resources such as networking and servers- file, compute and print servers. Therefore, their operating system is designed to copromise between individual usability and resource utilization.
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 (more often) through wireless modems. Due to power and interface limitations they perform relatively few remote operations. The operating systems are designed mostly for individual usabillity , but perfomance per amount of battery life is important as well.
Some computers have littile or no user view. For example, embedded computers in home devices and automobiles may havea numeric keypad, and may turn indicator lights on or off to show status, but mostly they and their operating systems are designed to run without user intervention.
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