The reason for this is to limit the amount of dirty pages in memory, which further reduces I/O overhead and disk fragmentation.

这么做可以限制内存中 “脏” 页面的数量，从而进一步减少 I/O 开销和磁盘碎片。

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Mr Huhne said the government would aim to encourage new entrants into the energy market, make clean energy more attractive to investors, develop reserve plants to ensure "the lights stay on" during periods of high demand, and limit the amount of carbon emissions from "dirty" power stations.

BBC: Huhne unveils 'seismic shift' in energy policy

Once the race began, he was a ruthless competitor (some preferred the term "dirty") who never seemed to go at less than his upper limit.

WSJ: Ayrton Senna | Aggression With Lucidity | By Richard B. Woodward