COBOL Is the Asbestos of Programming Languages

cobollegacy-systemstechnical-debtmainframeprogramming-historymigration

Abstraction: COBOL's pervasive legacy debt and the risks of AI-driven migration

Key points:

COBOL handles roughly $3 trillion in financial transactions daily; 80% of the 300 billion lines written by 2000 were COBOL; COBOL inefficiencies cost US GDP an estimated $105 billion in 2020
Designed in 1959 by a committee including Grace Hopper for machine-independent, plain-English business programming; the DoD requiring COBOL compilers drove its ubiquitous adoption
Fatal design flaw: no parameterization — modules share all data, so changes in one place can cascade system-wide, corrupting financial data or halting Social Security payments
The GO TO statement created "spaghetti code" that undermined the self-documenting design goal; Dijkstra called its use "a criminal offense"
IBM and others now sell AI-powered COBOL conversion tools (e.g., watsonx Code Assistant); simply converting to Java produces "JOBOL" — COBOL structure in Java syntax, losing readability without gaining maintainability
DOGE's effort to rewrite the Social Security Administration's COBOL codebase in months stalled; author is skeptical AI tools solve the underlying complexity problem

Connections: Ibm · Grace Hopper · Legacy Systems · Technical Debt