Modernization Prior to x86-64 Migration

A telecom provider prepared for an x86-64 migration by first modernizing their OpenVMS Integrity environment. Key updates included replacing outdated Java and database interfaces with OpenJDK 8 and FreeTDS. The migration also involved updating COBOL-based applications and replacing legacy ACMS interfaces. These changes reduced risks and ensured a smoother transition to x86-64. The customer received ongoing support from VSI Application Services.

A large telecommunication provider expressed strong interest in migrating their business-critical OpenVMS-based application environment from VSI OpenVMS on Integrity to VSI OpenVMS x86-64, however it was identified that certain application components used very old versions of some OpenVMS software products, and some key integrations with other systems relied upon no-longer supported third-party software. To reduce the risk and complexity of the migration to OpenVMS x86-64 it was therefore decided to address these matters on OpenVMS Integrity, rather than attempting to deal with them as part of the x86-64 migration project. The core application running on OpenVMS is comprised of several million lines of complex code written primarily in COBOL, with embedded SQL interacting with a Sybase database hosted on a UNIX platform and comprises a mixture of batch-oriented and ACMS-based transaction processing, serving many hundreds of concurrent users. Existing JNI interfaces were updated to use OpenJDK 8 for VSI OpenVMS in place of the old and no-longer supported HPE Java 6 JVM implementation, ACMS-based database interactions were updated to use the open-source FreeTDS API, and Attunity/Qlik-based ACMS interfaces were replaced with VSI's updated TPware/ACMSDI product. Given the scale and complexity of the application environment, this modernization work took some months to complete, however the work has been highly successful, and the end result is an application environment that is now well-positioned to be moved to OpenVMS x86-64 within the coming year. VSI application services supported the customer and their service provider throughout the course of the project, providing advice and technical assistance as needed.

What technical problems did that raise?

Interaction with the Sybase database was facilitated via JNI calls from COBOL into a JDBC-based Java layer using the no-longer supported HPE Java 6 JVM implementation, and it was therefore necessary to update the JNI interface to operate with OpenJDK 8 for OpenVMS, which required modifying the JNI code to use the correct pointer size (noting that the OpenJDK JNI uses 64-bit pointers while the older Java 6 JNI uses 32-bit pointers). Considerable care was taken to negate any thread-related issues caused by interactions between the multi-threaded JVM and the inherently non-thread-safe COBOL application environment, noting that OpenJDK 8 is considerably more sensitive to such matters than the older Java 6. For ACMS-based tasks it was not feasible to use OpenJDK 8 and the JDBC-based interface mechanism, and these interfaces were therefore replaced by calls to the open-source FreeTDS API. Some issues were encountered due to the FreeTDS API and utilities not fully supporting some newer Sybase features that are utilised by the application; however, it was possible to work around these issues without having to make any significant compromises.
Replacing Attunity/Qlik-based ACMS interfaces to desktop clients and other external systems with TPware/ACMSDI presented relatively few technical challenges, but it did necessitate porting the ACMSDI C client API to HP-UX, and a number of product updates were made to ACMSDI to support additional functionality required by the customer with regard to monitoring gateway usage and for running multiple gateway instances. Advantage was taken of the new SSL/TLS support in the ACMSDI gateway product to ensure that all network traffic between client applications and the gateway are encrypted.

What are the benefits

The primary benefit of this extensive modernization work is that the application environment is now well-placed to be ported to VSI OpenVMS x86-64, as it will not be necessary to make complicated and architecturally significant changes to the application environment as part of the porting work. The customer is now well-positioned to commence their x86-64 migration when the time is right. Given the scale and complexity of the application environment, it is to be expected that some problems will be encountered when migrating to x86-64, but as a consequence of this modernization work the project team will be much better placed to readily identify and resolve any such issues, and the overall risk profile of the project will be greatly reduced.