Editing Scalability (section)

===Horizontal or scale out{{anchor|Horizontal}}===
Scaling horizontally (out/in) means adding or removing nodes, such as adding a new computer to a distributed software application. An example might involve scaling out from one web server to three. [[High-performance computing]] applications, such as [[seismic analysis]] and [[biotechnology]], scale workloads horizontally to support tasks that once would have required expensive [[supercomputer]]s. Other workloads, such as large social networks, exceed the capacity of the largest supercomputer and can only be handled by scalable systems. Exploiting this scalability requires software for efficient resource management and maintenance.<ref name="parallel_arch" />