Embodiments of the invention provide a method of testing/adjusting magnetic disk devices, in which the method allows the tests/adjustments to be conducted by solving problems due to the data sizes and characteristics of test/adjustment programs. After assembly of a magnetic disk device, setup of various parameters, magnetic disk defect registration, and other test/adjustment steps are executed. Execution of the test/adjustment programs does not require a special test apparatus since they are executed in the magnetic disk device to be tested. In addition, the test/adjustment programs are formed up of multiple phases, and each phase is sequentially executed. Adoption of this program structure keeps the tests/adjustments clear from restrictions due to the data sizes and characteristics of the test/adjustment programs.