Miniature disk drive having embedded sector servo with split data fields and automatic on-the-fly data block sequencing

A programmable data sequencer within a disk drive including a rotating data storage disk defining a multiplicity of concentric data tracks, at least one of said data tracks including a sequence of fixed capacity data fields which are split into fractional field segments by intervening embedded servo sectors, each one of said data fields being preceded by a data field identification header including plural user byte count values, each one of the plurality of user byte count values indicating a user byte count storage capacity of a corresponding fractional field segment , the disk drive further including a data transducer controllably positioned by a servo head position control loop using information from the embedded servo sectors to pass over said at least one of said data tracks for reading a data field identification header and data field segments of each data field, and a buffer memory means for temporarily storing a fixed length user data block read from or written to the user data field;

• the programmable data sequencer connected to a read channel including the data transducer and to the buffer memory means, and comprising:
• control means for controlling transfer of a user data block between the buffer memory means of said disk drive and the segments of the data field and including a loadable byte sequence counter means for receiving and counting a present user byte count value as the data transducer passes over a corresponding contiguous segment,
• stack memory means for receiving from the read channel and for holding each user byte count value associated with the corresponding contiguous segment so that the storage capacity of user bytes of said segment is determined directly by said sequencer from said user byte count value, and
• stack memory control means for pushing each user byte count value being received from the read channel onto the stack memory means as the data transducer passes over the data field identification header, and for popping each user byte count value from the stack memory means to the loadable byte sequence counter means as the data transducer approaches the corresponding contiguous segment.