Back to ComputerTerms Both hardware adn software consist of hierarchical layers, with each lower layer hiding details from the level above. This principle of '''abstraction''' is the way both hardware designers and software designers cope with the complexity of computer systems. One key interface between the levels of abstration is the '''instruction set architecture''': the interface between the hardware and the low-level software. This abstract interface enables many ''implementations'' of varying cost and performance to run identical software. Back to ComputerTerms