Developed by IBM for its line of PS/2 desktop computers, Micro Channel Architecture is an interface between a computer (or multiple computers) and its expansion cards and their associated devices. MCA was a distinct break from previous bus architectures such as Industry Standard Architecture . The pin connections in MCA are smaller than other bus interfaces. For this and other reasons, MCA does not support other bus architectures. Although MCA offers a number of improvements over other bus architectures, its proprietary, nonstandard aspects did not encourage other manufacturers to adopt it. It has influenced other bus designs and it is still in use in PS/2s and in some minicomputer systems.