U.S. Philips Corporation

Helmut Schonwald

Eduard J Tercic

Miloslav Janak

Martin Ginsberg

Method and apparatus for dividing a track on a magnetizable information storage disc into sectors by writing sector identification information into the track. In order to optimize the storage capacity of a track on a magnetizable information storage disc the track is first filled with information bytes in response to the occurrence of the leading edge of an index pulse (a) derived from the disc in such manner that a predetermined number of bytes fill a portion (ix) of the track, followed alternately by sector identification bytes and further bytes defining the data field of the relevant sector in portions SK and DT respectively until the final group of sector identification bytes has been written into portion SKn, followed by further bytes into portion z until the leading edge of the next index pulse occurs. The (positive or negative) difference between the total number of bytes in the portions z+ix and the number of bytes in each of the data field portions (DT) is then determined and the write operation is then repeated in the same track with the number of bytes written in the data field portions modified in accordance with the difference determined, so that the difference is distributed uniformly over the various data field portions. The write operations are controlled by apparatus comprising counters which address a read-only memory containing the information bytes, an arithmetic unit for determining the difference, and a store storing the modified number of bytes to be written to define each data field.

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Munich, Georgia

Helmut Schonwald