IBM’s Customer Information Control System (CICS) is an on-line teleprocessing system developed by IBM. By providing a sophisticated control and service database/data communication system, the application developer can concentrate on fulfilling specific business needs rather than on communication and internal system details. CICS allows data to be transmitted from the terminal to the host computer, have the data processed, access files/databases, and then have data to be transmitted from the terminal to the host computer, have the data processed, access files/databases, and then have data transmitted back to the terminal. To accomplish that, CICS uses a telecommunication package such as VTAM or TCAM and various file access methods: VSAM, DL/1, DB2, etc.
The latest release CICS/ESA is Release 3.3.
Some of the new functionality includes:
1. Expanded features for the system programmer
2. Improved above the line storage utilization
3. New options for many CICS commands
4. Improved cross-platform communication facilities
Functionality
CICS provides the following support:
Data Communications
An interface between the terminal and printers with CICS via a telecommunication access method (TCAM or VTAM).
Multi Region Operation(MRO), through which more than one CICS region of a system can communicate
Intersystem Communication (ISC), through which one CICS region of a system can communicate with other CICS regions in other systems
Application Programming
Interfaces with programming languages such as COBOL and Assembler
Command level translator
An Execution Diagnostic Facility (EDF)
A Command Interpreter
Data Handling
An interface with database access methods such as DB2, DL/1, and VSAM
An interface with error checking and reporting facilities
Terminology:
CICS has its own language. Some of the language abbreviations of CICS are:
SIT System Initialization Table
PCT Program Control Table
PPT Program Processing Table
TCT Terminal Control Table
FCT File Control Table
TCP Terminal Control Program
TCTUA Terminal Control Terminal User Area
DCT Destination Control Table
TDQ Transient Data Queue
EIP Execution Interface Program
FCP File Control Program
ICP Interval Control Program
KCT Task Control Program
PCP Program Control Program
SCP Storage Control Program
TCA Task Control Area
TCTTE Terminal Control Table Terminal Entry
TSQ Temporary Storage Queue
TWA Task Work Area
AID Attention Identifier
CWA Common Work Area
MRO Multi Region Operation
QID Queue Identifier