subblock

SubBlock is a general term used in computing to describe a subdivision of a larger data block. The precise meaning and size of a sub-block vary by system, but it typically refers to a smaller, addressable unit contained within a fixed-size block that can be read, written, or managed independently. Sub-blocks enable finer-grained control, partial updates, and more flexible data organization in many technologies.

In storage and memory systems, sub-blocks are often used to permit partial updates or reads without touching the entire block. This can improve performance by reducing I/O and enabling more efficient wear leveling in flash-based devices. For example, a 4 KB block might be subdivided into smaller sub-blocks so that only the necessary portion is accessed or modified. Sub-block granularity also supports metadata management and more compact caching schemes.

Sub-blocks appear in other domains as well, including digital media processing and data structures. In image and video encoding, blocks of pixels or transform coefficients may be further divided into sub-blocks for localized processing. In databases and memory allocators, fixed-size blocks may be partitioned into sub-blocks to reduce fragmentation and to support variable-sized records within a uniform space.

Because the term is used across different technologies, the exact characteristics of a SubBlock—its size, alignment, and permissible operations—depend on the architecture or application. The concept serves to introduce a hierarchy within blocks to improve efficiency, flexibility, and scalability.