CPI-C (Common Programming Interface for Communication) (Linktionary term)

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CPI-C (Common Programming Interface for Communication)

Note: Many topics at this site are reduced versions of the text in "The Encyclopedia of Networking and Telecommunications." Search results will not be as extensive as a search of the book's CD-ROM.

CPI-C is a platform-independent API that interfaces to a common set of APPC (Advanced Program-to-Program Communication) verbs. It is simple and straightforward, and is portable across all platforms that support CPI-C. CPI-C is designed to provide a common environment for the execution of applications across IBM platforms, such as IBM MVS (Multiple Virtual Storage), VS (Virtual Storage), OS/400, and OS/2-based systems.

CPI-C provides an interface to LU 6.2 (logical unit 6.2) services. LU 6.2 is the technical name for IBM's APPC. LU 6.2 was developed to allow computers in IBM environments to set up their own communication sessions, rather than rely on a host computer to do so. LU 6.2 provides peer-to-peer communications between systems other than hosts, and allows those systems to run distributed applications such as file sharing and remote access. LU 6.2 supports the entire range of IBM platforms, including local area networks, desktop systems, and mainframes.

CPI-C is the preferred method for interfacing to LU 6.2. An older interface called the LU 6.2 Protocol Boundary also exists. IBM provides mapping to TCP/IP (Transmission Control Protocol/Internet Protocol). IBM has also worked out a way to interface Java applets and CPI-C.

IBM also submitted CPI-C to the X/Open organization (now The Open Group), which adopted it as a standard for developing client/server transaction-processing applications. IBM guides X/Open in its implementation of CPI-C and supports features such as full-duplex communications between CPI-C applications so programs can send and receive data at the same time. Multivendor distributed directory services are also supported, including X.500 and the directory services in The Open Group's DCE (Distributed Computing Environment). These services let applications locate users and resources without the need to know physical location information.