Recently, the demand of "Green Co mputing", wh ich represents an environmentally responsible way of reducing power consumption, and involves various environmental issues such as waste management and greenhouse gases is increasing explosively. We have laid g reat emphasis on the need to minimize power consumption and heat dissipation by computer systems, as well as the requirement for changing the current power scheme options in their operating systems (OS). In this paper, we have provided a comp rehensive technical review of the existing, though challenging, work on minimizing power consumption by computer systems, by utilizing various approaches, and emphasized on the software approach by making use of dynamic power management as it is used by most of the OSs in their power scheme configurations, seeking a better understanding of the power management schemes and current issues, and future directions in this field. Herein, we review the various approaches and techniques, including hard ware, software, the central processing unit (CPU) us age and algorith mic approaches for power economy. On the basis of analysis and observations, we found that this area still requires a lot o f work, and needs to be focused towards some new intelligent approaches so that human inactivity periods for co mputer systems could be reduced intelligently. one can focus; the objective being to reduce power dissipation. The motive behind this research on minimizing power consumption by PCs derives fro m a human tendency to leave the co mputer system running in between jobs, and as to when work is likely to be resumed is not at all predictable. The running computer system consumes electricity, and it is estimated that a typical desktop PC with a 17-inch flat-panel LCD monitor requires about 65-100 watts for the co mputer, and 35 watts for the mon itor. If left on 24×7 for one year, this system will consume 874 kilo watt hours of electricityenough to release 341 kg o f carbon dio xide into the atmosphere, and can also be equated to driving 1312 km in an average car [2]. On the other hand, by turning off this co mputer system when not in use (i.e., lunch times, weekends, during meetings) for one year, one can save as much energy as it takes to wash 464 loads of washing, or to run your microwave 24 hours a day for one week [3]. Even the various options used by the power scheme in the OS are not sufficient to save power, for example, screen savers are actually power wasters because when the screen saver kicks in, more power is consumed by the hard disk drive (HDD), CPU and monitor [4]. According to a study performed by IST at the University o f Waterloo, fo r a Pentiu m 4, 1.7 GHz mach ine without the monitor, it was found that during the system boot-up, power requirement is close to 110 watts; in id le mode, it uses close to 60 watts; and in fu ll power-saving mode, with no hard disk spin and the mach ine in sleep mode, power consumption is close 35 watts [5].
P. K. Gupta g raduated in Informat ics and ComputerEngineering fro m Vladimir State...
