Disk file or tape drive with high servo sample rate embedding additional servo sectors within individual data sectors

A method of writing data onto a disk containing servo samples in which the number of servo samples on the disk is increased with a minimal increase in overhead regions, comprising the steps of:

• dividing tracks on the disk circumferentially into a plurality of maxi sectors, each of which contains fields with servo and associated overhead information and a data field, and into at least one micro servo sector which is within each data field and contains only a portion of said information, all maxi sectors in each respective track being of the same length but of varying length track-to-track;
• rotating the disk relative to at least one recording head;
• using a phase continuous clock, writing data in the data fields;
• reading data by holding a read data VCO through each said micro servo sector without change in frequency;
• during reading of data, gating off detected data from the VCO through each said micro servo sector;
• at the end of each said micro servo sector, generating during writing of data an abbreviated VCO synchronization field and then a code constraint and synchronization nibble for resynchronizing the VCO with said data during subsequent reading of data;
• during said subsequent reading of data, gating on the detected data to the VCO at the beginning of said abbreviated VCO synchronization field;
• and
• interrupting writing and reading of data as each such micro servo sector passes by an associated head, whereby as each micro servo sector passes beyond said associated head, writing of data is resumed in such manner as to require minimal resynchronization of said data during reading.

A disk file comprising:

• at least one recording disk formatted in FBA with tracks divided into a plurality of substantially identical maxi sectors, each of which contains a servo field and an associated synchronization field and also a data field, and at least one micro sector located within each data field and containing a resynchronization field which is shorter than said synchronization field and contains only a subset of the information in the synchronization field;
• means for rotating each disk relative to at least one recording head;
• means, including said heads, for writing data in the data fields;
• phase continuous clocking means for synchronizing said data writing means;
• means, including said heads, for reading data in the data fields;
• other clocking means for synchronizing said data reading means with the data to be read;
• means for interrupting writing and reading of data as each micro servo sector passes by an associated one of the heads;
• and
• means for resuming writing and reading of data as each micro servo sector passes beyond said associated head for resynchronizing said data reading means with said other clocking means using the short resynchronization field, whereby the number of servo samples is increased in a manner transparent to the user with minimal increase in non-data regions.

A disk file comprising:

• at least one recording disk formatted in FBA with tracks divided into a plurality of substantially identical maxi sectors, each of which contains all fields with servo and associated overhead information and also a data field, and at least one micro servo sector located within each data field and containing only a portion of said servo and overhead information;
• means for rotating each disk relative to at least one recording head;
• means, including said heads, for writing data in the data fields;
• phase continuous clocking means for synchronizing said data writing means;
• means, including said heads, for reading data in the data fields;
• a read data VCO;
• means for reading data by holding the VCO through each said micro servo sector without change in frequency;
• means operative during operation of said writing means for generating the resynchronization field at the end of each said micro servo sector for resynchronizing the VCO with said data during subsequent operation of said reading means;
• means for interrupting writing and reading of data as each micro servo sector passes by an associated one of the heads, said means including
• (a) means operative during operation of said reading means for gating off detected data from the VCO through each said micro servo sector;
• (b) means operative during operation of said writing means for generating an abbreviated VCO synchronization field and then a code constraint and synchronization nibble;
• and
• (c) means operative during said subsequent operation of said reading means for gating on the detected data to the VCO at the beginning of said abbreviated VCO synchronization field;
• and
• means for resuming writing and reading of data as each micro servo sector passes beyond said associated head, whereby the number of servo samples is increased in a manner transparent to the user with minimal increase in non-data regions.

A method of writing data onto a recording medium containing servo samples in which the number of servo samples on the medium is increased with a minimal increase in overhead (non-data) regions, comprising the steps of:

• dividing tracks along the medium into a plurality of maxi sections, each of which contains a servo field and an associated synchronization field and a data field, and into at least one micro servo section which is within each of said data fields;
• preserving the contents of a data encoder/decoder throughout the micro servo section;
• moving the medium relative to at least one recording head;
• as each such micro servo section passes by an associated head, interrupting writing and reading of data;
• and
• as each micro servo section passes beyond the associated head, writing the preserved contents into that portion of the data field following each said micro servo section, whereby the need for data encoder/decoder flush is eliminated.