Chapter 1 STREAMS Overview

STREAMS defines a standard interface for character I/O within the kernel, and between the kernel and the rest of the system. STREAMS creates, uses and dismantles streams. A stream is a full-duplex processing and data transfer path between a driver in kernel space and a process in user space.

1.1 Overview

A stream is made up of three parts--a stream head, optionally one or more modules, and a driver. The stream structure is summarized in Figure 1-1. The stream head provides the interface between the stream and the user processes. The module processes data travelling between the stream head and the driver. The driver can be a device driver, which has associated hardware, or a software driver.

STREAMS facilities are available using a series of system calls, which interact with the driver.

Figure 1-1 STREAMS Format

For detailed information on STREAMS, refer to the STREAMS Programming Guide.