definition of a subsystem
subsystem. A unit or device that is part of a larger system. For example, a disk subsystem is a part of a computer system.A bus is a part of the computer. A subsystem usually refers to hardware, but it may be used to describe software.ubsystem. A unit or device that is part of a larger system. For example, a disk subsystem is a part of a computer system. A bus is a part of the computer. A subsystem usually refers to hardware, but it may be used to describe software.