XFS tries to cache as much data in memory as possible, and generally only writes things out to disk when memory pressure dictates that it do so.
xfs设法在内存中缓存尽可能多的数据，并且，通常仅当内存不足时，才会命令将数据写到磁盘时。
2
As the wind strikes the actuator disk on the upwind side, the pressure rises there, and the wind is deflected away from the disk, causing a large wake downstream of the disk.
当风力在逆风侧冲击促动盘时，那里的压力上升，并且风力从盘转向离开，引起盘下游的较大尾流。
3
Any of a group of eye diseases characterized by abnormally high intraocular fluid pressure damaged optic disk hardening of the eyeball and partial to complete loss of vision.