Blockaligned

Blockaligned is an adjective used in computing to describe data, I/O operations, or memory layouts that begin on or are organized around fixed-size blocks. A block-aligned construct starts at an address or offset that is a multiple of the block size, typically a power of two, such as 512 bytes or 4 KiB. This alignment can apply to storage on block devices, file-system pages, and network or protocol payloads that are processed in block units.

In practice, block alignment provides predictable, efficient I/O: reads and writes touch whole blocks, reducing partial-block copying and cache misses. It also simplifies metadata management and enables parallel I/O across multiple disks or cores. Blockaligned data often yields improved throughput and more consistent latency profiles, particularly in systems with high I/O demand or large-scale storage.

Contexts where blockaligned design matters include file systems and block devices, databases that organize data into fixed-size pages, backup and deduplication tools that process data in blocks, and cloud block storage services where user data is stored in block-sized chunks. Applications and libraries that stream or transfer data may also adopt block alignment to optimize buffering and transfer boundaries.

Implementation considerations include ensuring buffers and file offsets are aligned to the chosen block size, using memory allocation routines that guarantee alignment, and selecting I/O APIs that preserve alignment through the pipeline. Misalignment can lead to partial-block reads, extra copies, and reduced throughput. The term is commonly written as blockaligned or block-aligned, depending on style guides, and denotes a property rather than a separate standard.