Kr-85: A New Metric for Embedded System Technical Debt

In embedded systems, some design features deserve a more precise classification.

I propose we start qualifying certain embedded design features as “Kr-85.”

They’re radioactive, but they don’t explode immediately.
They just sit there, slowly contaminating everything ☢️

Half-life: 10 years.

The term “technical debt” is too vague.
It suggests something temporary, manageable, repayable.

But some non-decisions have half-lives longer than the product roadmap.

We need a unit to measure the long-term persistence. I propose the Kr85.

Examples:

• Unfixed hardware limitation: 1 Kr85

• Legacy bootloader nobody dares to touch: 2 Kr85

• Security architecture “to be improved later”: 5 Kr85

The higher the Kr85 accumulation, the harder future revisions become.

Maintenance costs increase.
Risk tolerance decreases.
Innovation slows down.
Reputation and trust collapse.

You might already feel the radioactivity.

Measure early. Contamination is real and silent. Decay is slow.

Not sure how to proceed?
We quietly keep Geiger counters in stock.