Tim BrayFeb 24

IBM crashes because we’re gonna YOLO a replacement for banking and credit-card back-ends, replacing billions of lines of COBOL with vibe code. Uh…

https://www.techbuzz.ai/articles/ibm-crashes-11-as-anthropic-threatens-cobol-empire

IBM Crashes 11% as Anthropic Threatens COBOL Empire

Anthropic's AI disrupts IBM's mainframe business, sending shares down 11% on threat

Show threadDan ConnollyFeb 24

@timbray how many COBOL codebases have good test suites? I suspect none.

How well do LLMs do without tests / types / guardrails?

Best practice AFAIK is to run in parallel with prod. I guess they could try that, but it would take like a monthly billing cycle or a quarter to test one change.

Show threadArthur van der HargFeb 25
@dckc @timbray I suspect that *all* extant COBOL codebases have excellent test suites. They are mission-critical applications, after all.
Show threadTim Bray
@ArtHarg @dckc I strongly suspect not, having written some of that code in the Eighties.
Feb 25 at 6:09amWeb
Show threadArthur van der HargFeb 25
@timbray @dckc And is that code part of a system that is still running?
Show threadIBBoardFeb 25

@timbray @ArtHarg @dckc They have a test suite of sorts.

It's called "the global economy". If that grinds to a halt or goes tilt because of banking issues then they have a bug 😬