International Business Machines Corporation

Arthur B Wills

George W Brock

Nelson K Arter

Frank B Shelledy

Ernest William Devore

Leslie R Zelenka

A forward/backward compatible apparatus and record member achieves multiple density by multiple track widths as well as multiple lineal densities. In a rotating head recorder a single head has a wide write gap followed by a plurality of narrow read gaps. In recording, narrower tracks--i.e., higher densities, the record medium is moved less than the width of the write gap for recording narrower tracks. The narrower tracks have the same width as the trailing read gaps. During readback, all read gaps are simultaneously operative. Signals from one of the read gaps are processed immediately, while signals from the remaining read gaps are buffered until a dead time occurs, such signals are then processed. The same principles are applicable to magnetic card and magnetic disk recorders. A record member of the disclosure employs a table of contents area always recorded at the lower density--i.e., widest track. The table of contents contains indicia indicating the track density as well as the lineal density of the other recording areas. The buffering also is employed to overlap seeks in a disk file for greater data accessibility.

Buffered recording

Write windings are deposited on a ferrite half yoke mounted on a titanium body, and magnetoresistive elements are deposited on another ferrite half yoke mounted on another titanium body. A center section comprising a sandwich of silver-copper shielding material between two ferrite sheets has glass-filled slots cut on one side thereof. The center shield is placed between the write and read sides with the write windings placed between pairs of glass-filled slots and with the magnetoresistive elements in contact with the opposite surface of the center shield. The write windings and the magnetoresistive elements are connected to connector blocks prior to final assembly, and the write and read sides and the center section are pressured together by bolts through two end pieces, forming a vise-like structure.

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Boulder, CO, United States of America

Arthur B Wills