The Case of the Vanishing Data: A COBOL Detective Story

 

The Case of the Vanishing Data: A COBOL Detective Story

The phone jangled harshly, shattering the peaceful quiet of Inspector COBOL's dimly lit office. He snatched the receiver, a plume of smoke curling from the cigarette dangling from his lips.

"Inspector COBOL here," he growled, his voice rough as gravel.

A frantic voice crackled through the line. "Inspector, thank heavens! We're losing data! It's just...vanishing! Poof! Gone!"

COBOL let out a long, slow exhale, the smoke forming a hazy question mark in the air. "Vanishing data, eh? Sounds like we've got a case of PIC X OCCURS DEPENDING ON gone wrong...or maybe a rogue MOVE statement. Either way, it's a job for yours truly."

He grabbed his trusty fedora and trench coat, a glint of determination in his weary eyes. "Don't worry, ma'am. Inspector COBOL's on the case."

---

The scene at the client site was one of controlled panic. Programmers huddled around flickering monitors, their faces illuminated by the eerie green glow of the mainframe console. Printouts littered the floor, a testament to their desperate attempts to find the source of the problem.

COBOL surveyed the scene, his sharp gaze taking in every detail. He examined the code, a labyrinth of MOVE statements, PERFORM loops, and nested IF conditions. He questioned the programmers, their answers a mix of confusion and frustration.

"The data seems to disappear between the input and output modules," one programmer explained, his voice laced with desperation. "We've checked the database, the network, even the hardware. Everything seems fine."

COBOL grunted, his eyes scanning the lines of code projected onto the wall. "Nothing's ever 'fine' when data goes missing. Let's see what we've got here..."

He pointed to a section of code with his magnifying glass.

COBOL

MOVE CUSTOMER-NAME TO CUSTOMER-RECORD.

"This MOVE statement, for example," COBOL rasped, tapping the line with his magnifying glass. "What are the PIC clauses for these fields?"

The programmer, a young man with nervous eyes, stammered, "Uh... CUSTOMER-NAME is PIC X(20), and CUSTOMER-RECORD is, uh, PIC X(15)..."

"Precisely," COBOL interrupted, a glint in his eye. "You're losing the last five characters of the customer's name. Truncation. A classic case."

The programmer blinked, realization dawning on him. "Oh...right."

"And that's just one potential culprit," COBOL continued, his voice taking on a pedagogical tone. "We need to examine every line of code, every data transfer, every calculation, to find the source of the leak. Think of data as water – it can leak out through the tiniest crack."

He launched into his investigation, meticulously tracing the flow of data through the program. He used the DISPLAY statement to examine the contents of variables at different points in the program, watching for any unexpected changes.

COBOL

DISPLAY "CUSTOMER-NAME BEFORE MOVE: " CUSTOMER-NAME.
MOVE CUSTOMER-NAME TO CUSTOMER-RECORD.
DISPLAY "CUSTOMER-NAME AFTER MOVE: " CUSTOMER-NAME.
DISPLAY "CUSTOMER-RECORD AFTER MOVE: " CUSTOMER-RECORD.

"See?" he explained, pointing to the output on the console. "The last five characters are gone. Vanished into thin air."

He enabled tracing to follow the execution path step by step, identifying any branches or loops that might be diverting the data.

TRACE ON....
* Code being traced...
TRACE OFF.

"The trace log will show us exactly where the program is going," he explained, scrolling through the output. "Like a trail of breadcrumbs leading us to the thief."

Hours turned into days, and the mystery deepened. COBOL encountered several red herrings – a suspected hardware glitch that turned out to be a faulty cable, a compiler error that was resolved by a simple recompile, even a rogue batch job that was innocently processing old data. But each lead proved to be a dead end.

Just as COBOL was about to admit defeat, he noticed something odd. A seemingly innocuous MOVE statement, tucked away in an obscure subroutine.

COBOL

01  WS-CUSTOMER-RECORD.
    05  WS-CUSTOMER-NAME     PIC X(20).
    05  WS-CUSTOMER-ADDRESS  PIC X(50).

01  CUSTOMER-FILE-RECORD.
    05  CF-CUSTOMER-ADDRESS  PIC X(50).
    05  CF-CUSTOMER-NAME     PIC X(20).

MOVE WS-CUSTOMER-RECORD TO CUSTOMER-FILE-RECORD.

"Aha!" he exclaimed, a triumphant grin spreading across his face. "The culprit!"

The fields in the working storage record and the file record were defined in a different order. This misalignment caused the address to be overwritten with the name, effectively erasing the address data. A subtle but critical error.

COBOL gathered the team, explaining his findings with the patience of a teacher and the authority of a seasoned detective. They stared at the offending code, a mixture of awe and embarrassment on their faces.

"Don't beat yourselves up about it," COBOL said with a shrug. "Even the best programmers make mistakes. The important thing is to learn from them. Always double-check your PIC clauses, use the DISPLAY statement liberally, and never underestimate the power of a good debugger."

He showed them how to fix the code and implement safeguards to prevent similar errors in the future. The team, relieved and grateful, showered him with praise.

As COBOL left the building, he paused to light another cigarette. He took a long drag, savoring the nicotine hit.

"Another case closed," he muttered to himself. "But there's always another bug lurking in the shadows. That's the nature of the beast, isn't it?"

He tipped his fedora and strode off into the night, the flickering neon lights reflecting in his tired but determined eyes. The world of COBOL was full of mysteries, and Inspector COBOL was ready to solve them all.

Image: Gemini