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

The SDM was officially launched in March 2016 at the CeBIT IT fair in Hannover, Germany. The key SDM components can be summarised as follows.

“The SDM COBOL runtime” provides a compatibility layer which enables customers to run end user applications compiled with and reliant upon the IBM COBOL runtime environment for z/OS. The SDM PL/I runtime runs end user applications compiled with IBM Enterprise PL/I for z/OS. They depend on Language Environment for low level-language related operations, such as obtaining system time or I/O operations.

“The SDM LE runtime” provides a compatibility layer which enables customers to run applications which were compiled with and reliant upon the low-level language runtime environment. The LE runtime supports COBOL, PL/I and Assembler programs utilising Language Environment functions.

“LzOnline” is the transaction server component of the SDM, comprising a compatibility layer which enables customers to execute applications and data that rely on the IBM CICS runtime environment in alternative environments.

“LzHierarchical” provides support for hierarchical databases, comprising a compatibility layer which enables customers to execute applications and data that rely on the IBM IMS runtime environment in alternative environments. LzHierarchical uses an open-source RDBMS, PostgreSQL, to provide compatibility with the data types and functions uniquely found in IMS, enabling mainframe applications and data to be rehosted in the new environment.

“LzRelational” provides support for relational databases, comprising a compatibility layer which enables customers to execute applications and data that rely on DB2 in alternative environments. LzRelational uses PostgreSQL user-defined types to provide compatibility with the data types and functions uniquely found in DB2, enabling mainframe applications and data to be rehosted in the new environment.

“LzBatch” delivers binary-compatible execution for batch applications written as JCL jobs in PL/I, COBOL and Assembler. LzBatch is a compatibility layer which enables customers to execute batch applications designed to run on IBM mainframes in alternative environments. Batch applications can run, without recompilation or data reformatting, in a Linux environment based on x86 or ARM hardware. JCL support is provided, enabling batch jobs to be submitted locally, by Network Job Entry (“NJE”), or via FTP-connected mainframes.

“SDM Core” provides the basic functionality to run the above components, including configuration files, catalog data sets, configuration file parser, debugging functionality, data set I/O manager, JSON parser and the SDM loader.

The Centerpiece Export tool (“CPX”) was developed by Winsopia to run on a customer’s IBM mainframe. CPX removes stub CSECTS contained in the customer application that call external services provided by the z/OS system or its runtime environments and replaces them with temporary placeholders. The customer application is imported into the SDM by the Centerpiece Import tool (“CPI”). The compatibility layer of the SDM replaces the removed stub CSECTS with new CSECTS (“wormholes”) that call replacement services in the alternative x86 Linux environment, using appropriate parameters, and provides replacement functionality that produces the same outputs that would be produced by the mainframe runtime environment.