Magnetic disk unit having magnetic disks and a magnetic head with a head slider which is in contact with surfaces of the magnetic disk

A magnetic disk unit including a plurality of magnetic disks mounted coaxially and equally separated, and a head driving unit for recording data on and retrieving data from the magnetic disks by a contact start-stop driving method in which a head slider on which a magnetic head is mounted is elastically in contact with and slides against at least one surface of each of said magnetic disks under a predetermined pressure in a state where the magnetic disk is stationary and in the initial state of rotation of the magnetic disk, in which the head slider floats up because of the rotation of the magnetic disk at a high speed, and in which the head slider is moved back and forth in the radial direction of the magnetic disk,

• the improvement comprising a surface of said magnetic disk against which said head slider slides having a configuration which is a duplicate of a surface configuration of an irregular processed layer on a surface of a substrate of said magnetic disk which is a non-magnetic substrate, and the surface of said disk substrate having protrusions whose surfaces are made flattened, and exhibiting a three-dimensional bearing curve in which a bearing ratio at a section taken at a depth from a top portion of the surface which corresponds to a portion of the surface deformed by a head load during the contact start-stop drive is between 0.1 and 10%.