The system bus model is a streamlined version of the Von Neumann model of computer architecture. The system bus models divides the computer into three individual subunits which are the CPU, memory and input/output. The system bus model deviates from the von Neumann model by combining the arithmetic logic unit (ALU) and the central processing unit (CPU) into a single unit.[1]
Communications
A key feature of the System bus model are the shared communication pathways all part of the system bus.[1] The system bus is composed of the data bus, address bus, control bus, power bus and sometimes an I/O bus.[1] The data bus is used for transfer of data between subunits while the address bus is used to transmit ___location information between units such as where the data is going or coming from.[1] The control bus is used to provide information as to how data is being sent.[1] The power bus is often not graphically depicted on models but is understood to exist. Furthermore, some more complex architecturs may also incorporate a separate I/O bus for transfer of data between Input/Output devices.[1]