Sequent Computer Systems was a computer company that designed and manufactured multiprocessing computer systems. They were among the pioneers in high-performance symmetric multiprocessing (SMP) open systems, innovating in both hardware (e.g., cache management and interrupt handling) and software (e.g., read-copy-update). Vestiges of Sequent's innovations live on in the form of data clustering software from PolyServe (subsequently acquired by HP), various projects within OSDL, IBM contributions to the Linux kernel, and claims in the SCO v. IBM lawsuit.