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请说明操作系统作业管理的功能。
2．作业调度算法是指按照什么样的原则来选取作业并投入运行，调度算法的合理性直接影响系统的效率，作业调度算法有哪些？
3．对算法的选择需要考虑哪些问题？

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The size and cost of the problem in southern Africa.

How small development schemes can help to solve the problem.

The Price of Idleness
1．Electrical devices such as CD players, vidoes and burglar alarms are consuming more energy in standby mode than when they are actually being used.
2．Maria Sanchez and her colleagues from the Lawrence Livermore National Laboratory in Berkeley, California, tested more than 50 small electrical applicances, from computers to doorbells, electric mowers, VCRs, and pool pumps. In the current issue of Energy Policy, they report that about half of all consumer electronics energy is used in standby mode. This costs American consumers ＄1 billion a year in wasted energy.
3．The researchers say that while electronic devices are lying dormant(休眠状态),running their clocks, maintaining internal memories or displaying their settings, they consume aroud 40 terawatt hours of electricity in the U.S. every year--enough to power a city such as Chicago or London. Many machines use almost as much power on standby as when working. For example, it takes 15 watts to play a typical CD, but an average of 11 watts to keep it on standby. Satellite TV systems use 14 watts when active and 14 watts on standby. Given the long hours these systems spend idling, each uses far more power in standby mode than when actually working.
4．"Bad design is largely to blame," says Sanchez. In a separate survey of CD players last year, her colleague Wolfgang Huber found that two machines with similar features used 28 watts and 2 watts respectively on standby. "For most products, we believe that standby power can be reduced to one watt or less," says Sanchez.
5．She backs proposals to set up a national labeling system to promote machines that meet this standard. Such a system could reduce standby power consumption in the U.S. by 50 per cent, says coauthor Alan Meier--more than 20 terawatt hours per year. Last month, electronics company Philips announced the launch of a device that can dramatically reduce the power used in standby mode.
A Factors Leading to Energy Waste
B Home Appliances
C Propsals to Cut Energy Consumption
D Energy Consumption Test
E Terawatt Hours
F Nonessential Electricity Use
Paragraph 2 ______

变配电室环境湿度很大但温度不高，对高压电气设备的安全运行影响不大。()