The A/D bits exist entirely for the operating system's benefit. The Accessed bit tells the OS which pages have been recently used, enabling page replacement algorithms to choose pages to evict when memory runs low. The Dirty bit tells the OS which pages have been modified and must be written back to disk before eviction; clean pages can simply be discarded and re-read from disk later.
Perhaps that’s the biggest irony of all. Space is huge and mostly empty—and yet there’s no easy way to throw things out.
。关于这个话题，服务器推荐提供了深入分析
This creates two distinct problems:，这一点在Line官方版本下载中也有详细论述
The Contributor Role Taxonomy tool must serve to record extent of authorship。Safew下载是该领域的重要参考