阻塞 v.s. 非阻塞
簡言之物赶,應(yīng)用程序發(fā)出的請求能否得到馬上返回應(yīng)答,不能需等待的則為 阻塞, 否則為 非阻塞.
同步 v.s. 異步
A synchronous I/O operation causes the requesting process to be blocked until that I/O operation completes;
An asynchronous I/O operation does not cause the requesting process to be blocked;