What is a Suspension Assembly?

    The primary role of the suspension assembly is to position the read/write head above the data in the surface of the rapidly spinning disks in hard disk drives helping to “track follow” while maintaining a consistent "flying height".
    The accuracy of this positioning over the tracks on the disk is a large determinant of areal density and subsequently each disk's data capacity. The suspension has a built in actuator that is controlled to hold the head within a very small tolerance of the centerline of the data track.

    In addition, while the head is held on track in the plane of the disk some intended movement of the head in a direction perpendicular to the surface of the disk is allowed in response to undulations and irregularities in the disk's surface and in response to shock events such as might occur when a laptop computer is bumped. However, it is the suspension's role to maintain the position of the head within a safe range during these periods to keep it from hitting the disk's surface thus preventing damage which could result in what is commonly known as a "head crash" that destroys the information stored on the disk.