Assembler: A hidden artifact in your legacy environment requiring special attention

Assembler conversion

There’s no question that monolithic legacy systems (e.g. mainframes) have been the workhorses of business computing for decades. In fact, nearly 80 percent of the world’s corporate data resides in, or originates from, mainframes running technology more than half a century old.

While these legacy systems have served their purpose in power and stability, they lack in adjusting to newer, elastic forms of IT required to adapt to digital transformation, the cloud and AI. But the process of giving up on big iron is complicated, full of (unwanted) surprises and costly.

One surprise that our customers face in transitioning their legacy systems is the presence and amount of code they have written in assembler.  This archaic, byte-oriented jumble of simple instructions called assembler is anything but simple. It can also be a major hindrance to modernization without the right solutions and an experienced team to help navigate it.

Assembler, sometimes called “assembly,” is a low-level programming language in which there is a strong correspondence between the program’s instructions and the architecture’s machine functions.

Having recently celebrated its 70th birthday, assembler was often selected because of its remarkably efficient use of system resources. Today, it comes with several challenges as you look to modernize your legacy environment:

  • Assembler programs are dependent on the underlying hardware architecture (unlike other mainframe languages like COBOL, FORTRAN, and PL/I, and are not supported on distributed hardware platforms).
  • Because assembler is byte-oriented, it’s common to come across bit- level instructions and pointers that do not have equivalents in other languages.
  • In addition, it is possible to have a single program that can be interpreted in many different ways depending on compile instructions. To account for this phenomenon, one assembler program may evolve into multiple programs in higher-level languages.

The combination of system specificity, instruction intent obscured by byte-orientation, and a general lack of expertise available in the marketplace make correct handling and modernization of assembler code extremely difficult.

It’s key to employ the unique combination of enterprise-class tools and hardened assembler expertise to reduce the high risk associated with migration.

Modern Systems’ automated tooling helps solve the assembler puzzle, delivering to customers a modern application with 100 percent like-for-like functionality as compared to the legacy assets, based on fully maintainable open systems. This reduces cost, allows for deeper integration, unshackles customers from outdated assembler, and enables customization to better meet business requirements. Best of all, once the application is converted, developers can extend application functionality in COBOL, Java, or C# directly without having to navigate assembler to do it.

Our solutions for assembler come with 30+ years of experience, and leverage a proven approach including the following process:

  1. Assess & Design
    • Automated application assessment
    • Operational and infrastructure assessment
  2. Transform
    • Automated data and database conversion
    • Automated application conversion
    • Operational and infrastructure implementation
  3. Test, Deploy & Support
    • Testing can be another “gotchas” for customers, as they don’t expect it to be so time-intensive. Typically, it accounts for more than half of the time required on the project.
    • Modern Systems works with customer teams to ensure a smooth and error-free transition into production.
    • Part of this transition includes the cooperative construction and testing of a go-live production cutover plan to reduce the potential risks associated with application deployments.

Read our white paper, No Assembly Required to learn more about assembler, which details our proven solutions, process and customer success stories for addressing assembler.

Our next blog post will detail our three step process above, so check back here to see the latest!

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