The Drinfeld-Manin construction of U(N) instanton is reformulated in the ADHM formulism,which gives explicit general solutions of the ADHM constraints for U(N)(N 2k-1) k-instantons.For the N < 2k-1 case,implicit results are given systematically as further constraints.We find that this formulism can easily be generalized to the noncommutative case,where the explicit solutions are also obtained.
