To "run native" is to execute software written for the computer's natural, basic mode of operation; for example, a program written for the Mac OS X operating system running under Mac OS X. Contrast with running a program under some type of emulation or simulation (see emulator and simulator). Running native has always been the fastest way to execute instructions on a computer. However, as computers become faster, the delays in emulated programs are less noticeable to the user. See native mode.