CICS/VS 1.3 was the first release designed, developed, announced and shipped by the IBM Lab at Hursley, England, under the leadership of Malcolm Beaver and Grahame Ford. As promised by Malcolm, after the shipment of the CICS/VS 1.2 product, heavily skewed to support of VTAM and SNA, the 1.3 product contained significant new support and a broad range of enhancements for all users of CICS.
The most notable enhancement in CICS/VS was the introduction of the command level CICS application programming interface (API) for COBOL and PL/I. In addition, CICS introduced its High Performance Option (HPO), reducing CPU cycles needed to perform VTAM-related functions.
CICS/VS 1.3 improved dynamic transaction backout (DTB) for data bases and other resources. CICS increased the number of preassembled modules and tables to reduce the time necessary to implement a new release of the product. The operating system's System Modification Program (SMP) was used for the first time with CICS/OS/VS 1.3 to offer improved system management for CICS-provided software.
CICS File Control further enhanced its support of VSAM files with support of alternate indexes, relative record data sets, a get previous command and reusable data sets.
CICS Terminal Control was enhanced in its support of the IBM 3790, 3770, 3660 and 3600 systems. TCAM support of SDLC lines and devices was also enhanced.
CICS/VS was announced on July 27, 1976 (P76-103). CICS/DOS/VS 1.3 was delivered on March 3, 1977 (P77-29) and CICS/OS/VS 1.3 was delivered on April 20, 1977 (P77-81). Considering that the CICS mission was transferred to the Hursley Lab in 1974-76, the design, development and shipment of a major, new release of CICS, was a significant accomplishment.
A number of the Hursley CICS Development staff had previously worked on the PL/I compiler when it was the responsibility of the Lab. Ken Davies and Peter Alderson, now part of CICS Development, used their compiler knowledge and skills to develop an improved application programming interface (API) for CICS. Initially, this new support was referred to as the High Level Programming Interface (HLPI) but after some time, this reference was dropped and the improved interface was simply referred to as the command level interface, or EXEC CICS.
Command Level CICS created a much improved separation of user application code and CICS-provided control programs (Terminal, Program, File Control, etc). The new interface removed the need for application programmers to understand and manipulate internal CICS control blocks and/or tables. In future versions and release of CICS, the product was able to add new function or change existing internals without impacting user programs.
Initially, there was some customer resistance to the new API because users felt that it would consume more CPU cycles to perform the same function as previously done with the CICS macro level interface. This concern was soon overcome when users experienced numerous benefits of the new command level interface. CICS programming was easier to learn, application coding errors were reduced, programs were easier to debug and maintain, and CICS systems, in general, became more reliable. User confidence in the command level interface grew rapidly.
Also new with CICS/VS 1.3 was the commitment by CICS to provide both object and source level comtability, obviating the need for customers to recompile their applications when migrating to a new release of CICS.
Copyright © 2003 - Yelavich Consulting, Sparks, NV
Click here
for other articles regarding the evolution of CICS.