singleprocessor

Singleprocessor refers to a computer system that contains one physical central processing unit (CPU). In contrast to multi-processor systems, which employ two or more separate CPUs, a singleprocessor system has a single CPU package that handles all instruction execution. The CPU may be single-core or multi-core; a multi-core single-processor configuration contains several processing cores within one chip, but remains a single physical processor overall.

Operations and performance: A singleprocessor's performance depends on the core's design, clock speed, cache, memory bandwidth, and instruction-level parallelism. In many modern CPUs, multi-threading and vector processing can provide concurrent work across several logical or hardware threads, even though there is only one processor identified in the system's hardware topology. The software scheduling layer and operating system treat each core or thread as separate execution contexts.

History and use: In early personal computers, most systems were truly single-processor with one socket. The rise of multi-processor servers in the late 1980s and 1990s, and later the shift toward multi-core CPUs in the 2000s, changed performance scaling strategies. Today, singleprocessor configurations are common in embedded devices, mobile devices with system-on-chip (SoC) designs, and budget desktops where a single CPU package suffices. Even in such systems, cores within the CPU can execute parallel workloads.

Limitations and considerations: Upgrading often means replacing the CPU or the motherboard if the socket changes; scaling beyond one processor requires additional sockets and architectural changes. Power, heat, and memory bandwidth constraints can limit performance gains in singleprocessor designs.

See also: single-core, multi-core, multi-processor, symmetric multiprocessing, system on a chip, virtualization.