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

CICS creates a data area called the Exec Information Block (“EIB”), which is used for direct communication between command level programs and CICS. CICS provides APIs to allow user application programs running in CICS to access the data area. CICS also provides resources to allow user application programmes to determine the format of the EIB for different programming languages, including Assembler, PL/I and COBOL. IBM fully documents the format of the EIB data area in CICS documentation.

The IBM supplied DFHEIBLK and DFHEIBLC copybooks defines the layout of an EIB.

LzLabs created two programs that displayed the location of fields in the EIB (their offset from the beginning) and attached them to DR 756 dated 24 August 2021, requesting Winsopia to provide and/or verify the layout of the structure of the DFHEIBLK copybook.

Winsopia compiled and executed the programs and Mr Lynch sent the offsets for the DFHEIBLK copybook fields to Mr Joot at LzLabs on 24 August 2021. Information on field names was included but not compiler listings or scrubbed modules.

Versions of the COBOL copybooks mapping the EIB were created in the SDM prior to DR 756. They were updated using information obtained in DR 756 and used to support customer COBOL applications that rely on the copybooks. Although there is an apparent discrepancy in dates, in that the relevant Git commit is dated 23 August 2021, prior to the DR response on 24 August 2021, DR 756 is recorded by Mr Joot as the source of the Git commit.