内存价格的波动周期已缩短至历史最短，甚至出现一个月内二次调价的极端情况。这种高频波动迫使手机厂商不得不采取动态定价策略。
Replaced by: Drizzle (21% → 100%)
，这一点在heLLoword翻译官方下载中也有详细论述
The tree starts as a single region covering the whole space. As points arrive, they get dropped into the region that contains them. When a region exceeds its capacity (the maximum number of points it can hold before splitting), the region divides into four children, and the existing points get redistributed.
Virtual memory is conceptually simple but potentially devastating to performance. Every memory access must go through segmentation (add segment base, check limit) and then paging (look up the page table). Naively, paging alone requires two additional memory reads per access -- one for the page directory entry, one for the page table entry.