Where does this come from, and can I check it?

NAND must be erased a whole block at a time, so controllers spread writes across spare blocks to even the damage. The figure is taken from JEDEC, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

Is this really a technology fact?

Yes. It sits on the Technology shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

What else can I read about it?

The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.

Mondo Knows Facts

Flash cells wear out after a few thousand erases

NAND must be erased a whole block at a time, so controllers spread writes across spare blocks to even the damage A NAND cell traps electrons through a thin oxide layer, and every program and erase cycle damages that layer slightly. Cheaper multi-level cells survive only a few thousand cycles, so the drive controller maps logical blocks onto fresh physical ones and retires the worn. Error correcting codes and reserved spare space keep a drive working as cells fail. It sits in Mondo's technology collection, one of 200 facts that each trace back to the reference below.

Where this comes from

JEDEC

Facts that can change over time are reviewed and updated. If something here looks wrong, Mondo would rather know than be confidently incorrect.

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Technology trivia

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Tags: nand, storage, reliability

Flash cells wear out after a few thousand erases: the short answers

Where does this come from, and can I check it?: NAND must be erased a whole block at a time, so controllers spread writes across spare blocks to even the damage. The figure is taken from JEDEC, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a technology fact?: Yes. It sits on the Technology shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.