The housing that chips come in for plugging into (socket mount) or soldering onto (surface mount) the printed circuit board. Creating a mounting for a chip might seem trivial to the uninitiated, but chip packaging is a huge and complicated industry. The ability to provide more and more I/O interconnections to a die (bare chip) that is increasingly shrinking in size is an ever-present problem. In addition, the smaller size of the package contributes as much to the miniaturization of cellphones and other handheld devices as the shrinking of the semiconductor circuits. See CDIP, CERDIP, CERQUAD, CLCC, DIP, flatpack, PLCC, QFP, MCM, MCP, SOP, SOIC, SOJ, TSOP and ZIP.