CMS Pipelines
CMS Pipelines implements the pipeline concept under the VM/CMS operating system. The programs in a pipeline operate on a sequential stream of records. A program writes records that are read by the next program in the pipeline. Any program can be combined with any other because reading and writing is done through a device independent interface. Overview. "CMS Pipelines" provides a CMS command, codice_1. The argument string to the codice_1 command is the pipeline specification. PIPE selects programs to run and chains them together in a pipeline to pump data through. Because CMS programs and utilities do n't provide a device independent stdin and stdout interface, "CMS Pipelines" has a built-in library of programs that can be called in a pipeline specification. These built-in programs interface to the operating system, and perform many utility functions. Data on CMS is structured in logical records rather than a stream of bytes. For textual data a line of text corresponds to a logical record. In "CMS Pipelines" the data is passed between the stages as logical records. "CMS Pipelines" users issue pipeline commands from the terminal or in EXEC procedures. Users can write programs in REXX that can  be used in addition to the built-in programs. Example. A simple example that reads a disk file, separates records containing the string "Hello" from those that do not. The selected records are modified by appending the string "World!" to each of them; the other records are translated to upper case. The two streams are then combined and the records are written to a new output file. In this example, the codice_3 stage reads the input disk file and passes the records to the next stage in the pipeline. The codice_4 stage separates the input stream into two output streams . The primary output of codice_4 (records containing Hello) passes the records to the codice_6 stage. The codice_6 stage modifies the input records as specified in its arguments and passes them to its output. The output is connected to codice_8 that combines records from all input streams to form a single output stream. The output is written to the new disk file. The secondary output of codice_4 (marked by the second occurrence of the codice_10 label) contains the records that did not meet the selection criterion. These records are translated to upper case (by the codice_11 stage) and passed to the  secondary input stream of codice_8 (marked by the second occurrence of the codice_13 label). The pipeline topology in this example consists of two connected pipelines. The "end character" (the codice_14 in this example) separates the individual pipelines in the pipeline set. Records read from the input file pass through either of the two routes of the pipeline topology. Because neither of the routes contain stages that need to buffer records, "CMS Pipelines" ensures that records arrive at codice_8 in the order in which they passed through codice_4. The example pipeline is presented in 'portrait form' with the individual stages on  separate lines. When a pipeline is typed as a CMS command, all stages are written on a single line. Features. The concept of a simple pipeline is extended in these ways: "CMS Pipelines" offers several features to improve the robustness of programs: History. John Hartmann, of IBM Denmark, started development of "CMS Pipelines" in 1980. The product was marketed by IBM as a separate product during the 80's and integrated in VM/ESA late 1991. With each release of VM, the "CMS Pipelines" code was upgraded as well until it was functionally frozen at the 1.1.10 level in VM /ESA 2.3 in 1997. Since then, the latest level of "CMS Pipelines" has been available for download from the CMS Pipelines homepage for users who wish to explore new function. The current level of "CMS Pipelines" is included in the z/VM releases again since z/VM 6.4, available since November 11, 2016. An implementation of "CMS Pipelines" for TSO was released in 1995 as BatchPipeWorks in the BatchPipes/MVS product. The up-to-date TSO implementation has been available as a Service Offering from IBM Denmark until 2010. Both versions are maintained from a single source code base and  commonly referred to as "CMS/TSO Pipelines". The specification is available in the Author's Edition.