A combination of elements that will function together to produce the capabilities required to fulfill a mission need, including hardware, equipment, software, or any combination thereof, but excluding construction or other improvements to real property. A system shall be considered a major system if it is estimated by the Under Secretary of Defense for Acquisition and Technology to require: 1. An eventual total expenditure for research, development, test, and evaluation of more than $75,000,000 in fiscal year 1980 constant dollars (approximately $115,000,000 in fiscal year 1990 constant dollars), or 2. An eventual total expenditure for procurement of more than $300,000,000 in fiscal year 1980 constant dollars (approximately $540,000,000 in fiscal year 1990 constant dollars).