From the course: Migrating COBOL Apps

COBOL today - COBOL Tutorial

From the course: Migrating COBOL Apps

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COBOL today

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- [Narrator] When mainframes became popular in the 1960s, computers took input from punch tape or punch cards and delivered output on computer line flow. Applications were written using batch processing techniques and programmers coded them in assembler language. Punch cards eventually gave way to interactive terminals, often called green screen terminals because they displayed green characters on a black background. We still use this kind of interactive mode today in what's known as console or shell output. It was in this environment that the next development took place, high-level languages. The main languages to emerge were ALGOL, the Algorithmic Language, with more advanced variants, such as ALGOL 68, Fortran, the formula translation language used by scientific programs, and COBOL, the business-oriented language. These languages were all designed for card or tape input, batch mode operation, and printer output with a console input/output. COBOL was the language of choice for many large commercial businesses, being used initially for customer records and accounting systems. It's a simple but verbose language which didn't come with many libraries of preexisting code, so most algorithms had to be coded as part of the application. As a consequence, COBOL applications can be very large, with core business systems often having over a million lines of custom code. The documentation for such systems tended to be sparse and often not updated as the code was maintained. A lot of COBOL applications have been written with some observers estimating, even in 2019, that there were over 200 billion lines of COBOL code in use, and there's more being written each day. The investment in COBOL software has been immense and it's proved difficult to justify moving away from it. As a result, the language hasn't disappeared. It's continued pretty much in its traditional form, but with better contemporary support. IBM has continued to support COBOL and its mainframes and a number of Windows and Unix style COBOL compilers exist. IDEs such as Visual Studio Code and tools such as Notepad++ recognize the COBOL syntax and provide the benefits of code syntax, highlighting, and debugging. There continues to be a significant amount of COBOL written, but the number of new programmers coming into the market with COBOL skills is small. COBOL continues to be relevant and migration projects will be critical in not only reducing the amount of legacy COBOL, but also helping upskill the next generation of COBOL programmers.

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