"In creating a software architecture, system considerations are seldom absent. For example, if you want an architecture to be high performance, you need to have some idea of the physical characteristics of the hardware platforms that it will run on (CPU speed, amount of memory, disk access speed) and the characteristics of any devices that the system interfaces with (traditional I/O devices, sensors, actuators), and you will also typically be concerned with the characteristics of the network (primarily bandwidth). If you want an architecture that is highly reliable, again you will be concerned with the hardware, in this case with its failure rates and the availability of redundant processing or network devices. On it goes. Considerations of hardware are seldom far from the mind of the architect. So, when you design a software architecture, you will probably need to think about the entire system-the hardware as well as the software. To do otherwise would be foolhardy. No engineer can be expected to make predictions about the characteristics of a system when only part of that system is specified."