Unix Network 2

I/O model

1block IO (BIO)2Non-block IO (NIO)3IO multiplexing (select/ pselect, poll/ epoll)4Sigal IO 5asynchronized IO (AIO)

IO are divided two parts
first is waiting the data ready
second is copy the data from the core to the userspace

1~4 are most the same.

BIO blockNIO keep pollingIO mutilplexing  block on select/pollSIGIO block and wait for the signal from the corethey all block when data copy from core to user space

AIO does not need to wait.