by Tega AkuruliThe Forgotten Programming Languages That Still Power the World
The Silent Code Running the Modern World
Every time you withdraw money from an ATM, board a flight, or make an online purchase, you rely on software. Much of that software wasn’t written in Python, JavaScript, or Go. It was crafted decades ago in languages that many developers today have never used. These forgotten programming languages are the backbone of global technology, quietly ensuring that planes fly, banks process transactions, and hospitals store patient data securely.
While tech headlines often celebrate new languages and frameworks, the legacy systems that keep the modern world running tell a different story. Behind the sleek frontends of fintech apps or cloud dashboards lies a foundation of code written in COBOL, Fortran, Ada, and assembly, still running smoothly after decades of service.
This article uncovers these unsung heroes of code the legacy programming languages powering the modern world. It explores their origins, lasting importance, and how they continue to shape industries in 2025 and beyond.
Why Forgotten Languages Still Matter
In software development, trends change quickly. Every few years, a new language promises faster, cleaner, or smarter code. Some systems built in the 1960s and 1970s still outperform their modern counterparts in reliability and efficiency.
The reason? These older languages were designed for mission-critical systems environments where failure is not an option. Think banks, hospitals, air traffic control, and government databases. Migrating these massive systems would cost billions and risk catastrophic downtime.
So, while flashy new languages dominate job boards, these legacy codes quietly power the digital world’s most essential operations.
1. COBOL — The Language That Runs the Financial World
- Created: 1959
- Full Name: Common Business-Oriented Language
COBOL is perhaps the most famous of the “forgotten” programming languages and the most indispensable. It was designed to process massive volumes of data for businesses and governments. More than 60 years later, COBOL still powers most of the world’s banking and insurance systems.
Where COBOL Is Used Today
- Banking Systems: Around 80% of in-person transactions rely on COBOL programs.
- ATMs and Credit Card Processing: Billions of daily transactions run through COBOL code.
- Government Databases: The U.S. Social Security Administration and IRS still depend on COBOL.
Why It Still Matters
COBOL’s reliability, stability, and ability to handle high-volume transactions make it irreplaceable. Rewriting decades of COBOL code in a new language would be costly and risky, one small error could halt global financial operations.
Even in 2025, demand for COBOL specialists is rising, often bringing retired engineers back to maintain critical systems.
2. Fortran — The Scientist’s Workhorse
- Created: 1957
- Full Name: Formula Translation
Fortran is the oldest high-level programming language still in active use. It was originally built for scientific and engineering computations, and it still dominates fields like meteorology, physics, and aerospace research.
Where Fortran Is Used Today
- Weather Forecasting: Global climate models rely on Fortran’s numeric accuracy.
- NASA and Space Research: Many spacecraft trajectory simulations still run on Fortran.
- High-Performance Computing: Supercomputers use optimized Fortran code for simulations.
Why It Still Matters
Fortran’s efficiency in mathematical computation is hard to match. Today, Fortran compilers generate some of the fastest numerical code possible. Researchers trust it because it’s proven, stable, and consistently optimized for modern hardware.
Fortran may not trend on GitHub, but it powers the supercomputers modeling everything from hurricane paths to nuclear fusion.
3. Ada — The Language of Safety-Critical Systems
- Created: 1980
- Named After: Ada Lovelace, the first computer programmer
Ada was designed by the U.S. Department of Defense to standardize and secure military software development. Built for safety, concurrency, and reliability, it’s the go-to language for aerospace, defense, and transportation systems.
Where Ada Is Used Today
- Air Traffic Control Systems
- Commercial Aircraft Avionics (Airbus and Boeing software)
- Railway and Metro Systems
- Defense Missiles and Radar Systems
Why It Still Matters
Ada is nearly bug-proof by design. Its strict type system and compile-time checks prevent many runtime errors common in C or Java. This makes it perfect for environments where a failure could lead to loss of life.
Even modern derivatives like SPARK Ada are still being developed for safety-critical software, which keeps Ada relevant in industries prioritizing security over speed.
4. Assembly Language — The Root of All Code
- Created: 1949 (Early form)
- Type: Low-level, hardware-specific language
Assembly is often called the language of the machine because it communicates directly with a computer’s CPU. Though it’s complex and time-consuming to write, Assembly gives unmatched control over hardware.
Where Assembly Is Used Today
- Embedded Systems and Microcontrollers
- Firmware for Medical and Industrial Devices
- Performance-Critical Games and Graphics Engines
- Operating System Kernels (Linux, Windows)
Why It Still Matters
Modern languages rely on compilers that ultimately translate their instructions into Assembly. This means every app, no matter how advanced, still rests on this ancient foundation.
Assembly remains vital for optimizing hardware-specific performance, especially in embedded systems, robotics, and gaming consoles where speed and precision matter most.
5. Lisp — The Original AI Language
- Created: 1958
- Full Name: List Processing Language
Before Python or TensorFlow, there was Lisp the language that pioneered artificial intelligence programming. Lisp introduced concepts like recursion, garbage collection, and dynamic typing all staples in modern programming.
Where Lisp Is Used Today
- AI Research and Symbolic Computation
- Robotics and Natural Language Processing
- AutoCAD and CAD Scripting Systems
Why It Still Matters
Lisp’s flexibility and adaptability make it ideal for experimental research. Even though mainstream AI has shifted to Python, Lisp remains embedded in legacy AI frameworks, showing its lasting design brilliance.
6. RPG — The Enterprise Workhorse
- Created: 1960
- Full Name: Report Program Generator
RPG, developed by IBM, was designed for business reporting and transaction systems. It’s still widely used in IBM’s midrange systems, especially for enterprise-level ERP and inventory management.
Where RPG Is Used Today
- Retail and Logistics Systems
- ERP Solutions on IBM i (AS/400)
- Financial Reporting Tools
Why It Still Matters
RPG’s simplicity and integration with IBM systems make it essential for long-standing enterprise applications. Many global corporations depend on RPG-based systems to process millions of transactions daily.
7. Pascal — The Forgotten Academic Foundation
- Created: 1970
- Designed By: Niklaus Wirth
Pascal was originally a teaching language, built to instill good programming structure and logic. It formed the foundation for many later languages and tools, including Delphi, Turbo Pascal, and influenced C and Java.
Where Pascal Is Used Today
- Education and Training Programs
- Legacy Desktop Software (Delphi apps)
- Embedded Control Systems
Why It Still Matters
Pascal may not power modern startups, but its structured programming principles still shape software education. Many engineers who learned Pascal have a better understanding of code logic than those who start with purely object-oriented systems.
8. PL/I — IBM’s Multitasking Powerhouse
- Created: 1964
- Full Name: Programming Language One
PL/I was designed to combine the scientific power of Fortran with the business capabilities of COBOL. Although it never reached their fame, it became a critical language for mainframes and data processing.
Where PL/I Is Used Today
- Banking and Finance Systems
- Insurance Claims Processing
- Government Data Centers
Why It Still Matters
PL/I can handle both scientific calculations and business data manipulation—a rare versatility. IBM continues to support PL/I for its mainframes, making it another quiet giant in enterprise computing.
9. Forth — The Minimalist Control Language
- Created: 1970
- Designed For: Embedded and real-time systems
Forth is a stack-based language known for its simplicity and efficiency. It’s used in environments where hardware control and a minimal memory footprint are essential.
Where Forth Is Used Today
- Spacecraft Control Systems (NASA missions)
- Robotics and Industrial Automation
- Instrumentation and Embedded Devices
Why It Still Matters
Forth’s small size and direct hardware control make it ideal for low-resource environments. Its influence can be seen in modern IoT and microcontroller programming.
10. Smalltalk — The Origin of OOP
- Created: 1972
- Created By: Alan Kay and the Xerox PARC team
Smalltalk is the birthplace of object-oriented programming (OOP) the paradigm that powers C++, Java, Python, and nearly every modern language today.
Where Smalltalk Is Used Today
- Research and Academic Institutions
- Legacy Business Applications
- User Interface Framework Design
Why It Still Matters
Smalltalk introduced graphical interfaces, integrated development environments, and live object manipulation ideas that still shape software design. Though niche, its influence remains everywhere.
Why We Still Depend on These Languages
Despite their age, these legacy programming languages persist because they offer unmatched:
- Reliability: Decades of proven stability in mission-critical environments.
- Performance: Optimized to run efficiently on limited hardware.
- Compatibility: Deep integration with infrastructure built before modern tech existed.
- Cost Efficiency: Rewriting millions of lines of legacy code is too costly and risky.
These systems may not make headlines, but they are too important to fail.
The Hidden Workforce: Developers Who Keep Legacy Code Alive
As younger generations shift toward modern languages, there’s a global shortage of developers skilled in COBOL, Fortran, Ada, and PL/I. Governments and corporations are scrambling to train new programmers in legacy systems a surprising career niche offering lucrative opportunities.
Even tech giants like IBM and Oracle now run training programs specifically for legacy developers to ensure these critical systems stay functional.
The Future: Modernizing Without Replacing
Rather than rewriting everything from scratch, many organizations are turning to modernization through integration connecting legacy systems with modern interfaces, APIs, and cloud environments.
Examples
- COBOL to Cloud: Banks wrapping COBOL systems with REST APIs for digital banking apps.
- Fortran + Python: Scientists integrating legacy Fortran models with Python for AI-driven simulations.
- Ada + C++: Aerospace firms combining Ada’s safety with C++’s flexibility.
This hybrid approach preserves the reliability of old systems while embracing the innovation of new technology.
The Timeless Code That Runs Tomorrow
Innovation may shape the future, but legacy code maintains the present. The forgotten programming languages powering global infrastructure are testaments to durability, efficiency, and engineering skill.
Every time a plane lands safely, a hospital updates patient records, or a transaction is completed in seconds, these ancient lines of code show that technology doesn’t need to be new to be essential.
In the end, these languages remind us that the future of computing isn’t just about what’s next it’s also about what still works flawlessly after half a century.