HT-2021-000363 - [2025] EWHC 532 (TCC)

CICS includes a feature called basic mapping support used by user application programs to present screens to an IBM 3270 terminal user and obtain information provided to that screen by a user. User programs, when using CICS APIs to present a 3270 screen, can provide attributes for fields within that screen, specified as numbers. CICS provides a resource that can be used by user programs written in languages such as Assembler, COBOL, C and PL/I, source code for each programming language that assigns a variable to each number.

As helpfully explained by Mr Stephens, using variable names rather than a number can make it easier to program; programmers do not need to research the number for each variable (such as a colour). Variables also make it easier for other programmers to read and to understand the program code.

The CICS copybook, DFHMBSA, is IBM supplied source code that defines the standard field attributes and printer control characters used by 3270 terminals (or terminal emulators).

CICS documentation provided by IBM lists the names of each of the variables and a description of the attribute to which it relates but does not specify the actual number assigned to each variable.

LzLabs created a COBOL program that displayed the value of each of the variables and attached it to DR 715 dated 23 July 2021, requesting Winsopia to provide the numeric values for the CICS DFHBMSCA copybook constants.

Winsopia compiled and executed the program and, on 26 July 2021, Mr Lynch sent the test results back to Mr Joot of LzLabs Canada. This did not include the compiler listings or scrubbed modules.

Initial implementation of the SDM version of DFHBMSCA was created by LzLabs on 19 March 2019. Following the response to DR 715, Mr Joot updated the SDM file, by replacing all placeholder values with the copybook constant values supplied by Winsopia. Against the Git commit dated 26 July 2021, Mr Joot identified DR 715 as the source of the constant values.