In computing, a loaer is the part of an operating system that is responsible for loading programs from executables (i.e., executable files) into memory, preparing them for execution and then executing them. The loader is usually a part of the operating system's kernel and usually is loaded at system boot time and stays in memory until the system is rebooted, shut down, or powered off. Some operating systems that have a pageable kernel may have the loader in the pageable part of memory and thus the loader sometimes may be swapped out of memory. All operating systems that support program loading have loaders. Some embedded operating systems in highly specialized computers run only one program and have no program loading capabilities and thus no loaders, for example embedded systems in cars or stereo equipment.