Adaptec, Inc.

Nicholas S Assouad

John S Packer

Fred A Kool

A disk drive system for a constant density recording (CDR) format disk has a microprocessor which generates CDR words from split values stored in a ROM. The CDR words indicate how embedded servo sectors split data sectors into data fields. In one embodiment, during a seek to a track, the microprocessor stores in a data buffer the CDR words for requested data sectors on the track. Alternatively, track CDR tables are stored in the data buffer during start-up and altered during a seek. A disk sequencer reads CDR words from the data buffer into a FIFO buffer as required to locate splits in data sectors. Alternatively the microprocessor writes the CDR word directly into the FIFO buffer. Typically, the microprocessor writes CDR words for a data frame, into the FIFO buffer, during a servo burst preceding the data frame, but the microprocessor can wait two or more servo bursts before writing CDR words for two or more data frames. Data transfer for each requested data sector is initiated by a sector pulse. The CDR words can identify requested data sectors. Otherwise, the microprocessor suppresses sector pulses for unwanted data sectors or qualifies sector pulses with a signal that confirms a data sector is requested.

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Boulder, CO, United States of America

Nicholas S Assouad