There’s a reason you don’t do things like that…

Apparently nobody in that software team has heard about Knight Capital. They reused a flag and that coupled with a deployment failure that only lasted ~45 minutes caused an over 400 million dollar loss nearly bankrupting the entire company. Ultimately they ended up combining with another company.

The immediate cause of the incident was a deployment failure that left one of eight servers running outdated code, creating an inconsistency in how the system interpreted incoming instructions. The new software reused a flag associated with a legacy function known as “Power Peg,” which had been disabled but not removed from the codebase, and on the unpatched server this flag activated obsolete logic that continuously generated child orders in response to parent orders that the system did not correctly recognize as already filled.

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