# username = "root" # default
The x86 protection model is notoriously complex, with four privilege rings, segmentation, paging, call gates, task switches, and virtual 8086 mode. What's interesting from a hardware perspective is how the 386 manages this complexity on a 275,000-transistor budget. The 386 employs a variety of techniques to implement protection: a dedicated PLA for protection checking, a hardware state machine for page table walks, segment and paging caches, and microcode for everything else.
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But when Fretwell looked at the satellite pictures, he saw few signs of the birds.
美国作家莫娜 · 辛普森：做最好的自己