Single-machine mode is a computing mode in which multiple processors or multiple cores are controlled by a single operating system and can access shared resources, such as disks and memory. More simply, single-machine mode for high-performance procedures means multithreading on the client machine. In single-machine mode, the OPTGRAPH procedure runs multiple concurrent threads on a multicore machine in order to take advantage of parallel execution on multiple processing units. For information about running the OPTGRAPH procedure in single-machine mode, see the SAS OPTGRAPH Procedure: Graph Algorithms and Network Analysis.