The read-write head is an important component of a PC's hard disk technology. This particular object is an air-bearing disk, that is, the heads float on a cushion of air maintaining separation of the heads with the disk, thus overcoming damage to the information stored on the disk, and the wear and tear associated with friction. The donor initiated the development of the air bearing head for the Read-Write Corporation in 1991.

The manner in which the air bearing read-write head works could be likened to an aircraft taking off. The spinning disk creates a cushion of air between the head and the disk surface much like an aircraft travelling at speed down a runway attains lift. Like an aircraft, the read-write head also lands when the disc speed is reduced and the air cushion is thus reduced (at shut-down and of course the head is 'landed' when the computer is not powered up). If the head actually makes physical contact with the disk surface, the disk would be damaged (a 'head crash') and information would be lost. To overcome this, heads typically land in a 'landing zone' that does not contain user data. This particular head, the Tri-pad air bearing, was designed to introduce an intermediary stage in the take off and landing stage such that the read-write head remains in pseudo contact with the disk over a wide range of speeds. Pseudo contact is the term coined by the Read-Rite Corporation that refers to the greatly reduced separation space between the disk and the read-write head. The smaller the separation, the more accurate the information transfer between the head and the disk can be, and thus a stronger signal amplitude. Pseudo contact was pioneered by the Read-Rite corporation due to the growing need for a read-write head that could operate at a minimal separation from the disk without actual contact. This product achieved this.

Damian McDonald
September 2007

The Read-Rite Corporation produced more than 12 million Tri-pad air bearing read-write heads in their first year of high volume production. Western Digital and Maxtor are companies that used the Tri-pad air bearing head in their hard disk technology from 1995.

The Read-write air-bearing is a component of a computer's hard disk. As the name suggests, the head floats on a cushion of air above the platter, thus minimising wear and tear from friction.

In late 1991, Peter Bischoff, Vice President of Research and Development at the Read-Rite Corporation in California, USA, endorsed the development of a Tri-pad air bearing that would address the need for closer proximity reading in read-write heads in computer hard disks. The donor, Manager of Advanced Products in Research and Development at the Read-Rite Corporation, initiated the design and development of the Tri-pad air bearing along with Chuck Gooden and Edgar Williams. The three of them went on to become the co-inventors of the US Patent 'Tri-Pad Air Bearing Slider', number 5,473,485. This object is an example of the successful product.

Tri-pad read-write head, metal / plastic, made by Read-Rite Corporation, Milpitas, California, United States of America, 1998

The Read-Rite air-bearing is made from a light metal alloy. It is a flat, elongated triangle in shape with two holes cut into it at the base of the triangle, and two smaller holes at the tip. The head that reads and writes the information onto the hard disk is situated at the tip of the triangle. There is an electrical wire running from the head that has been cut off at about two centimetres.

Made: California, USA; 1995 - 1998


Used: 1991

2007/144/1

1995 - 1998

4 mm