i/c(Power-on self-test)

Power-on self-test

Power-on self-test (POST) is the common term for a computer, router or printer's pre-boot sequence. The same basic sequence is present on all computer architectures. It is the first step of the more general process called initial program load (IPL), booting, or bootstrapping. The term POST has become popular in association with and as a result of the proliferation of the PC. It can be used as a noun when referring to the code that controls the pre-boot phase or when referring to the phase itself. It can also be used as a verb when referring to the code or the system as it progresses through the pre-boot phase. Alternatively, this may be called "POSTing."

For embedded systems power-on self-test (POST) refers to the testing sequence that occurs when a system is first powered on. POST is software written to initialize and configure a processor and then execute a defined series of tests to determine if the computer hardware is working properly. Any errors found during the self-test are stored or reported through auditory or visual means, for example through a series of beeps, flashing LEDs or text displayed on a display. Once the POST sequence completes, execution is handed over to the normal boot sequence which typically runs a boot loader or operating system. POST for embedded systems has been around since the earliest