IOmodels

I/O models in unix network programming

通过<UNIX Network Programming(Volume1,3rd)> 学习unix下的io模型
there are five I/O models that are available to us under Unix:

• blocking I/O
• nonblocking I/O
• I/O multiplexing (select and poll)
• signal driven I/O (SIGIO)
• asynchronous I/O (the POSIX aio_functions)

As we show in all the examples in this section, there are normally two distinct phases for
an input operation:

1. Waiting for the data to be ready
2. Copying the data from the kernel to the process
   For an input operation on a socket, the first step normally involves waiting for data to
   arrive on the network. When the packet arrives, it is copied into a buffer within the kernel.
   The second step is copying this data from the kernel's buffer into our application buffer.
   在unix下有五种I/O模型:

• 阻塞I/O
• 非阻塞I/O
• 多路复用I/O
• 信号驱动I/O
• 异步I/O
  所有的例子中,输入有两个阶段的操作:

1. 等待数据就位
2. 从内核中copy数据到进程中