The Legacy of COBOL: A Programmer's Perspective

When was the last time you coded in COBOL? This question might be challenging for many programmers, as COBOL is often associated with retro technology and not the cutting-edge development environments we see today. For me, who has had limited experience with COBOL, the last time I coded in it was in the early 1980s. However, COBOL is still very much alive and in use, particularly in the banking and financial sectors, where legacy systems are crucial. If you have questions about COBOL programming or specific tasks, feel free to ask!

COBOL and Legacy Systems

COBOL, or Common Business-Oriented Language, was once the cornerstone of business computing. Though it's often overshadowed by more modern languages, COBOL continues to play a significant role in many legacy systems, particularly in the financial and banking sectors. This is due to the fact that these systems have been in place for decades and massive investments have been made in their development and maintenance. Updating these systems to the latest technologies is a monumental task, and often, the most efficient and cost-effective approach is to continue using COBOL rather than rewriting everything in a more modern language.

A COBOL Factorial Calculation Example

Program Listing

Here is a simple example of a COBOL program for calculating factorials:

       IDENTIFICATION DIVISION.
       PROGRAM-ID. FactorialProgram.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  Number         PIC 93.
       01  Factorial      PIC 918 VALUE 1.
       01  I             PIC 93 VALUE 1.
       01  End-Of-Input  PIC X3.
       PROCEDURE DIVISION.
       MAIN-LOGIC.
           DISPLAY 'Enter a number:'.
           ACCEPT Number.
           IF Number LE 1 OR Number GT 12
               DISPLAY 'Please enter a number between 1 and 12'.
               STOP RUN
           END-IF.
           PERFORM VARYING I FROM 1 BY 1 UNTIL I GT Number
               MULTIPLY Factorial BY I GIVING Factorial
           END-PERFORM.
           DISPLAY 'Factorial of ',Number,' is: ',Factorial.
           DISPLAY 'Additional inputs?'.
           ACCEPT End-Of-Input.
           IF End-Of-Input  'Y'
               PERFORM MAIN-LOGIC
           ELSE
               DISPLAY 'Thank you for using the factorial calculator.'
           END-IF.
           STOP RUN.

In this program, the user is prompted to enter a number. The input is checked to ensure it falls within the specified range (1 to 12). If the input is valid, the program calculates the factorial and displays the result. The program then asks if the user would like to calculate another factorial. If the user enters 'Y', the process repeats; otherwise, the program ends.

COBOL in Action: Year 2000 Transition

The transition from the year 1999 to 2000 marked a significant challenge for many organizations, especially in the financial sector. The Y2K issue, or the two-digit year bug, had caused a lot of anxiety. Many companies were required to search for and fix every use of a two-digit year designator in their financial computers and programs. For one major aerospace company, this meant a massive effort to ensure their systems would not crash on the midnight of December 31, 1999, to January 1, 2000. This transition was notably smooth, with the systems accepting the new date without any issues. This event highlighted the critical role that legacy systems play in critical sectors and the importance of maintaining and updating these systems over time.

My own experience with COBOL dates back even further. In 1967, I worked on an IBM 360/50 where I wrote a Fortran program that was slow at reading a magnetic tape. A colleague suggested using COBOL for better input handling. I then learned enough COBOL to write the necessary PIC statements, allowing the program to switch from Fortran to COBOL and back. This resulted in a much faster initial read and subsequent processing. However, that was the extent of my COBOL experience. Reflecting on it now, COBOL was more appropriate for the input handling task, but the rest of the program could have been written in COBOL without the need to mix languages.

In conclusion, while COBOL may be considered an outdated language by some, its presence in legacy systems ensures it remains relevant. Its robustness and the importance of maintaining these systems make it a valuable skill for any programmer working in the financial or banking sectors. If you have any questions or need further clarification about COBOL, feel free to ask!