Loader
In computing, a loader program is a program that performs the functions of a linker program and then immediately schedules the executable for execution, without necessarily creating an executable file as an output. Loader programs are useful for prototyping, testing, and one-off applications.One such program was an integral part of Gene Amdahl's original OS/360 operating system, and the facility is continued through its descendents including MVT, MVS and z/OS.