To see why exponential-time algorithms are generally unusable in practice, consider a program that makes 2"n" operations before halting. For small "n", say 100, and assuming for the sake of example that the computer does 1012 operations each second, the program would run for about 4 × 1010 years, which is the same order of magnitude as the age of the universe. Even with a much faster computer, the program would only be useful for very small instances and in that sense the intractability of a problem is somewhat independent of technological progress. However, an exponential-time algorithm that takes 1.0001"n" operations is practical until "n" gets relatively large.