High Quality Content by WIKIPEDIA articles! Power-On Self-Test (POST) refers to routines which run immediately after many digital electronic devices are powered on. Perhaps the most widely-known usage pertains to computing devices (personal computers, PDAs, networking devices such as routers, switches, intrusion detection systems and other monitoring devices). Other devices include kitchen appliances, avionics, medical equipment, laboratory test equipment—all embedded devices. The routines are part of a device`s pre-boot sequence. Once POST completes successfully, bootstrap loader code is invoked.