Low-power hard disk drive system architecture

A disk-drive system, operating from a power source, for storing and retrieving data, said disk-drive system comprising:

• a) rotating media means for storing data including a plurality of occurrences of predetermined data including a prior occurrence and a present occurrence of said predetermined data;
• b) data transfer means for reading and writing data with respect to said rotating media means including reading said plurality of occurrence of predetermined data, said present occurrence being read subsequent to said prior occurrence of said predetermined data;
• c) power transfer means, coupled to the power source, for providing power to said data transfer means;
• and
• d) control means for enabling said power transfer means to provide power to said transfer means, said control means including means, responsive to said prior occurrence of said predetermined data as read by said data transfer means, for enabling said power transfer means to provide power to said data transfer means to permit reading of said present occurrence of said predetermined data.

A disk-drive system operating from an external source of power and responsive to an external host computer for the storage and retrieval of data, said disk-drive system comprising:

• a) media means for storing data on a rotating media wherein a portion of the data is stored in primary data fields at predetermined locations;
• and
• b) control means for managing the transfer of data between the external host and said media means, said control means including:
• i) interface means for interacting with the external host computer, including receiving a request for the transfer of data with respect to a predetermined subset of said primary data fields;
• ii) data transfer means, including a read/write transducer, for transferring data to and from said media means;
• iii) power transfer means, responsive to a power enable signal, for providing power to said data transfer means to permit the reading of data from said media means;
• and
• iv) processor means, responsive to said interface means and including timing means for providing a cyclic timing signal synchronized to the rotation of said primary data fields by the reading of predetermined data by said read/write transducer, for controlling the selection of said predetermined subset of primary data fields for the transfer of data, said processor means, responsive to said timing signal, discretely determining for each cycle of said timing signal whether to provide said power enable signal to said power transfer means for a respective one of said primary data fields and providing said power enable signal to said power transfer means for the duration of the rotation of any one of said predetermined subset of primary data fields by said read/write transducer.

A method of controlling a hard disk drive having a disk for storing data in a plurality of concentric tracks, each track including a plurality of data sectors and each sector including control and user data, a spin motor for rotating the disk, an actuator for positioning a head with respect to a predetermined track for reading control and user data, the period of time for a sector to rotate past the head defining a sector period, and control electronics for controlling the actuator in response to control data read from the sectors of the predetermined track, the control electronics including a first section and a second section, said second section including read/write data channel electronics, said method comprising the steps of:

• a) providing power to said first section;
• b) providing power selective to said second section for at least a portion of each sector period to enable said second section to read control data;
• and
• c) withdrawing power from said second section during each sector period if user data is not to be transferred during that sector period.

A hard-disk drive control system, comprising:

• a) disk media for storing data in concentric tracks, each track including a plurality of sectors, each sector including embedded control data;
• b) means for rotating said disk media;
• c) means for sensing said embedded control data including a sensor positioned over a surface of said disk media, said sensor sensing said embedded control data of a sector as said sector passes under said sensor;
• d) switching means for providing a first power source, said first power source providing power in response to a first signal applied to said switching means;
• e) means for processing control data sensed by said sensing means, said processing means including a first electronic signal-processing subsection coupled to said sensing means, said first electronic signal-processing subsection being powered by said first power source;
• and
• f) control means, responsive to said processing means, for selectively providing said first signal to said switching means with respect to each of a consecutive series of sectors as each sector passes under said sensor, said first signal being provided for a period less than that required for a corresponding sector of said consecutive series of sectors to pass under said sensor;
• whereby the total power consumed by said hard disk drive control system is be reduced by said control means providing said first signal only when data is to be read from said disk media.

A disk drive coupleable to a host computer system for the transfer of user data in response to a host read data request, said disk drive comprising:

• a) a disk providing for the storage of data at a surface of said disk, wherein said data is stored in a plurality of concentric tracks, wherein each said concentric track includes a plurality of sectors, and wherein each said sector includes a control data field and a user data field;
• b) a transducer positionable in opposition to a predetermined one of said plurality of concentric tracks to permit the reading of data from predetermined ones of said sectors;
• c) a power supply unit that provides a first source of power and that, responsive to an enable signal, selectively provides second source of power;
• d) a spin controller that includes a spin motor and a commutation power driver circuit to provide for rotation of said disk in response to a first control signal, said spin controller being operative from power from said first source of power;
• e) an actuator controller that includes an actuator motor and arm assembly mechanically coupled to said transducer and an actuator power driver circuit to provide for the positioning said transducer in response to a second control signal, said actuator controller being operative from power from said first source of power;
• and
• f) a controller coupled to said spin controller and said actuator controller, said controller including
• i) a first subsection that provides said first control signal to said spin controller to control the rotation of said disk and said second control signal to said actuator controller to control the positioning of said transducer, and
• ii) a second subsection that includes electronic circuitry, electrically coupled to said transducer, for reading data from said disk and that generates a periodic control signal from predetermined data as read by said transducer from predetermined ones of said control data fields,
• iii) said controller including a timer, responsive to said periodic control signal that periodically provides said enable signal, said controller separately selecting to maintain the provision of said enable signal for each of said predetermined ones of said sectors for a predetermined period of time selected from a set of predetermined periods of time including
• a first predetermined period of time that is approximately equal to the rotational period of time that a predetermined one of said control data fields is opposite side transducer, and
• a second predetermined period of time approximately equal to the rotational period of time that said one of said control data fields and one of said user data fields is opposite said transducer,
• iv) said first subsection being operative from power from said first source of power and said second subsection being operative from power from said second source of power;
• whereby said second subsection is periodically provided power and is thereby periodically operative for the reading of data from said control data fields of said predetermined ones of said plurality of sectors, and
• whereby said second subsection is selectively unpowered and thereby inoperative for the reading of data from at least one of said user data fields of said predetermined ones of said plurality of sectors.