Chapter 25. STREAMS

The STREAMS facility replaces the old BSD serial character I/O mechanism. The replacement was done to clean up some of the procedures in order to make them more efficient, portable, and extensible. It was first introduced in SunOS version 4.0. The Solaris 2 version of STREAMS is not much different from the SunOS 4.x implementation; some changes were made to support multithreading, but the basic internal structure remains unchanged.

The STREAMS specification defines a set of system calls, kernel functions, and interface requirements to handle general serial character I/O. It can support terminals (ttys), pipes, and a lot of network protocols. The kernel functions that perform the work are divided up into loadable modules, all of which deal with the same basic method of passing data back and forth (message blocks, or mblks , placed in linked lists called queues ).