The Evolution of CICS

The Evolution of CICS: CICS/VS Establishes Itself (1973-1975)

CICS/VS was announced for the DOS and OS platforms on February 1, 1973 (P73-21). IBM had announced virtual storage systems and new operating systems to support the new environments. CICS/VS was CICS' corresponding announcement. The most notable change for CICS was to adapt to virtual storage management, but more was done for CICS during the early period of the new environments.

In the 1973 announcement, CICS introduced the idea of controlled shutdown and warm start. Prior to this, CICS did not provide such a function and every start-up was essentially a cold start. The CICS/VS product also introduced journaling, which became the basis for emergency restart and backout, delivered in later releases of the product.

CICS Basic Mapping Support (BMS) was introduced with the pre-VS product but was enhanced as part of the CICS/VS introduction, to include message routing, terminal paging and message switching. CICS/VS also introduced support for VSAM, and improved its interfaces to DL/I in both the DOS and OS environments. CICS/OS/VS 1.0 became available in February 1974 (P74-5) and CICS/DOS/VS 1.0 became available in March 1974 (P74-10).

Both the CICS/DOS/VS and CICS/OS/VS products were enhanced in April 1974 (P74-16) with the addition of VTAM support for the 3600, 3650, 3790 and 3780. These enhancements were included in the 1.1 release and gave early support for the new VTAM, SNA and SDLC environments. More was to come with the announcement and delivery of CICS/VS 1.2, the last release designed and developed by CICS Development in Palo Alto, California and the first release shipped by CICS Development at Hursley, England.

The CICS/VS 1.1 release also included emergency restart for CICS/DOS/VS and a multi-threaded DL/I interface for CICS/OS/VS.

CICS/VS 1.0.1 became available for DOS and OS in October 1974 (P74-56), in which the primary enhancements were related to improving virtual storage management.

The CICS/DOS/VS product announced more enhancements in November 1974 (P74-61), adding CPU console support, a subset option and a starter system, to ease installation and operation.

In February 1975, CICS continued the rapid expansion of function for both CICS/DOS/VS and CICS/OS/VS with the announcement of data set (file) backout and emergency restart (P75-11).

In April 1975, CICS announced major enhancements for both of the CICS/VS products (P75-24). These enhancements included:

Data base emergency restart
Temporary storage emergency restart
Interval control data recovery
VSAM shared resources
Console override of SIT parameters
Auxiliary trace facility

These and other enhancements were made available as part of the CICS/VS 1.1.1 releases which shipped in June 1975 (P75-30). In February 1976, CICS announced 1.2 which was heavily oriented to the major IBM emphasis on VTAM, SNA and the new SDLC terminal devices and controllers. At this time, CICS/VS had established its base support for virtual storage systems and included primary functions such as emergency restart. The remainder of the 1970s would focus on improving the CICS programming interface and introducing client/server and distributed systems functions.