hesela.devLogical block address
A logical block address (LBA) is the numeric address used to select a logical block within a storage device or namespace.
An LBA is a logical position, not physical-media placement. Retain the device or namespace identity. [2]
For linear zero-based data addressing, byte offset = LBA times data bytes per block. LBA 8 starts at byte 4096 with 512-byte units or 32768 with 4096-byte units. Eight blocks from LBA 8 span LBAs 8-15. These are calculations, not observed media operations.
NVM Command Set 1.0e Read NLB=7 requests eight blocks, whereas NSZE=8 counts addresses 0-7. That namespace cannot contain the preceding request. Metadata is separate from block data size. [1]
For integer N >= 0 addressable blocks, integer start S >= 0 and decoded integer count C > 0, require S < N then C <= N - S: S=7, C=1 fits N=8; C=2 or S=8 does not. This checks only address-space containment, not command success. NSZE bounds addresses; NCAP bounds simultaneous allocation. [1]
In NVM Command Set 1.0e, NSFEAT.THINP=0 requires NCAP=NSZE and permits constant NUSE=NCAP; THINP=1 requires allocated-block tracking. With ANA support, NUSE and NVMCAP are zero in ANA Inaccessible or ANA Persistent Loss for the controller-namespace relationship. Therefore zero proves neither an empty namespace nor erased data; NUSE is not filesystem used space. Record controller/path state. NVMCAP is in bytes, not blocks, and need not equal NSZE times block data size. [1]
Linux 6.17 block-statistics read/write/discard sector counters use 512-byte units, regardless of logical-block size. Do not multiply them by a discovered 4096-byte sector size. [3]
Relations
Limitations
- An address alone does not establish physical placement, allocation state, atomicity or durable completion. [2, 1]
Citations
- NVM Express NVM Command Set Specification 1.0e (2024), definitions 1.4.3.2-6, section 2.1.1 and Figures 47-48, 97
- SNIA Dictionary: logical block and logical block address, edition generated 4 November 2026
- Linux 6.17: block layer statistics, read/write/discard sector units
Sources & caveats
- Primary-source review; illustrative integer arithmetic only. No device commands, benchmark or new field observations. NVMe revision is pinned; neither NLB encoding nor NSZE meaning is generalized to every storage field.