The Evolution of CICS

The Evolution of CICS: CICS/OS/VS 1.7 - a BIG (!) Release (1985)

Big isn't always best, but once the horse is out of the barn, you run with it. The biggest new news was Resource Definition Online (RDO) for VTAM terminals. It was big in several ways. First, one developer reportedly coded 40 KLOC (lines of code) all by himself. Secondly, in addition to RDO for terminal definition, terminal definitions could also be autoisntalled.

Then, add to that, the release introduced EXEC CICS SET and INQUIRE which satisfied virtual every user's need to dynamically determine some system value or conversely, to alter that value while running. And without accessing internal CICS control blocks. Big stuff!

CICS/OS/VS 1.7 introduced many enhancements to File Control such as dynamic open/close, dynamic allocation/deallocation, automatic VSAM VERIFY, and the user now could allocate multiple local share resource (LSR) pools. And this was only the tip of the iceberg.

CICS increased its support of RACF as an external security manager. ISC and MRO had numerous enhancements to improve intercommunication among VTAM or IRC-connected CICS systems. The recently added CICS Monitoring Facility (CMF) was enhanced making it more valuable to the user. VTAM-related enhancements included such things as CLSDST PASS, enabling the user to pass an LU connection to another CICS system.

Task Control improved CICS maximum number of tasks (CMXT) as a means of limiting the use of CICS resources. The runaway task interval was converted from real time to task time, providing a more accurate measure. SPOOLREAD and SPOOLWRITE were added to the product to enable users to output CICS data via JES. RESP and RESP2 were added to the command level application programming interface, giving the application programmer a new means to handle exception conditions in a structured programming manner.

The new RDO for terminals was built on the the previous introduced capability of dynamically defining other CICS resources such as programs, transaction, maps, etc. RDO for terminals eliminated the need to recompile CICS' Terminal Control Table (TCT) when adding new terminals or changing their definitions. RDO for terminals could be accomplished using the dynamic add transaction (CEDA). A dramatic new capability was autoinstall for terminals. A terminal, not previously known to CICS, could log onto CICS, and using a model resource definition, a TCT terminal entry (TCTTE) could be dynamically created for use with the given system.

All this was well and good, however given so much new RDO code, it was the early users (the classic bleeding edge) who rushed to use it, and wound up working with the IBM Support Center and CICS Development to get it right. Internally within IBM this raised a lot of management and procedural questions regarding one developer producing so much code in a single release. The good news, in the end, was that it all began to fall in place and today almost all users rely on RDO and autoinstall for terminals.

The CICS Project at SHARE submitted a detailed requirement that CICS provide a command level API facility by which application programs could dynamically determine the content of various CICS variables or values. Additionally, users wanted the ability to alter, some if not all of those variables. CICS/OS/VS 1.7 delivered the new SET/INQUIRE commands which satisfied almost all customer requirements of this kind. What was important here was that it provided a means by which users could determine and/or alter values, without access to CICS internals. This was not meant to be secretive but rather to isolate customer application code from CICS-provided code and control blocks. It enabled future releases of CICS to change its internals without impacting existing customer applications.

CICS/OS/VS 1.7 was announced on July 23, 1985 (285-266) and shipped on December 17, 1985 (285-484).