nand-open-block · unknown · also partially programmed NAND block

Open NAND block

An open NAND block is a partially programmed erase block whose remaining pages have not yet completed programming.

Related Observatory article: Open NAND block on hesela.com

Calibration: A page group may span writes made before and after a programming pause. Its pages then have different retention or read-disturb histories, so shared read-voltage offsets can mismatch some pages. [1]

Boundary: This is an internal NAND condition, not an NVMe open-zone state or a measure of filesystem free space.

Relations

related: qlc, qlc-ssd, nand-erase-block, read-retry, data-retention, read-disturb

Citations

Papandreou et al. - Open Block Characterization and Read Voltage Calibration of 3D QLC NAND Flash, IRPS 2020, Sections III-IV, Figures 5-9 (accessed 2026-10-16)

Sources & caveats

IRPS 2020 reports laboratory QLC characterization, not a fleet failure rate. [1]
Chip identities and sample count are not specified; P/E cycles are normalized. [1]

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