An embedded system and a general-purpose computer are two separate sorts of computers. Unlike general-purpose computers, embedded systems can only run one program at a time. Embedded systems, unlike general-purpose computers, cannot be programmed. Embedded systems are frequently bound by runtime, but general-purpose systems must be able to perform more fast

The input component of a computer ...     sends data from an external device to computer memory     stores instructions and data     sends data from computer memory to an external device     sends signals to control the actions of various functional units within a processor according to program instructions     operates on data to perform computations

Through a technique called multitasking, an operating system manages the activities of many running programs simultaneously. Capacity is often measured in terms of a system's ability to perform multiple tasks at once.