The consultancies and vendors that actually do Assembly / HLASM modernization work, and what each one specializes in. This is a general market overview, not a paid placement or an endorsement.
The original platform vendor
IBM still owns the compilers and the hardware most COBOL, PL/I, RPG, and HLASM code runs on. Its own consulting arm pairs migration and refactoring services with tooling for code analysis and COBOL-to-Java transformation on IBM Z, alongside watsonx Code Assistant for Z, an AI-assisted code explanation and conversion tool launched in 2024.
Best for: Staying on the mainframe and modernizing around it, rather than off it.
Mainframe-to-cloud migration specialist
Astadia supports major mainframe environments including IBM z/OS and applications built in COBOL, Assembler, Natural, and Adabas. Its FastTrack Migration Factory has been used to migrate databases from IDMS to DB2 and convert Enterprise COBOL to Micro Focus COBOL running off the mainframe.
Best for: Organizations with a mandate to exit the mainframe on a defined timeline.
Automated code transformation preserving business logic
TSRI's JANUS Studio automatically analyzes and converts COBOL, JCL, CICS, IMS, Assembly, and more than 30 other languages into Java, C#, or C++ on multi-tier or microservices architectures, aiming to preserve the original business logic rather than reinterpret it. TSRI holds the AWS Mainframe Modernization Competency.
Best for: Large COBOL or Assembly codebases where preserving exact business logic during conversion matters more than a full architectural redesign.
HLASM to Java or C# migration
Offers turnkey modernization of HLASM assembler code and its associated mainframe databases to relational models, converting to Java or C# for cloud or on-premises deployment.
Best for: Organizations ready to fully retire assembler code rather than wrap or maintain it in place.
HLASM migration to Linux and cloud, output stays readable
Specializes specifically in HLASM assembler migration, aiming to produce natural, readable, maintainable code on the target platform rather than a literal line-for-line translation.
Best for: Shops worried that an automated conversion will produce output no one can actually maintain afterward.
Deep source-code analysis and custom-goal translation
Uses its DMS Software Reengineering Toolkit to parse and deeply analyze source code (including Assembler), producing translations tuned to the customer's specific goals for the resulting code structure and quality, rather than a one-size-fits-all conversion.
Best for: Complex or unusual codebases where a generic conversion tool's default output isn't good enough.