LSI

LSI is an initialism that can refer to several distinct concepts in information technology and electronics. Common uses include latent semantic indexing, a technique in information retrieval; large-scale integration, a historical term for densely packed integrated circuits; and LSI Corporation, a former semiconductor company known for storage controllers.

Latent Semantic Indexing (LSI) is a method for processing text to improve information retrieval by capturing underlying concepts rather than relying solely on exact term matches. It operates on a term-document matrix and uses singular value decomposition to reduce dimensionality, revealing latent structures that connect related terms. This approach helps address synonymy and polysemy, enabling broader or more relevant search results. LSI gained prominence in the 1990s and influenced early search engines and text analysis, though it has been largely superseded by advanced machine learning models in modern systems. Practical use requires substantial text corpora and computing resources, and results can degrade with noisy data or domain shifts.

Large-Scale Integration (LSI) is a historical term for integrated circuits containing a high density of transistors, preceding very-large-scale integration (VLSI). In the 1960s through the 1980s, LSI referred to ICs with thousands to tens of thousands of transistors, enabling more capable digital logic and memory arrays. The term helped mark advances toward more complex microprocessors, memories, and system-on-chip devices, and it became largely obsolete as industry standardization moved to VLSI and beyond.

LSI Corporation was a U.S. semiconductor company known for storage controllers used in hard disk drives, SSDs, and RAID products. It grew through acquisitions and product lines such as RAID controllers and host bus adapters. In 2013–2014, LSI was acquired by Avago Technologies (later Broadcom Limited), and its storage business became part of Broadcom.