Computer machinery and equipment, including memory, cabling, power supply, peripheral devices, and circuit boards. Computer operation requires both hardware and software. Hardware design specifies a computer's capability; software instructs the computer on what to do. The advent of microprocessors in the late 1970s led to much smaller hardware assemblies and accelerated the proliferation of computers. Today's personal computers are as powerful as the early mainframes, while mainframes are now smaller and have vastly more computing power than the early models.