Disk drive having a register set for providing real time position variables to a host

A computer system comprising:

• a host computer for providing data transfer commands;
• a disk drive for receiving the data transfer commands and for providing data to the host;
• a host interface for connecting the host computer to the disk drive;
• the host computer comprising:
• a host memory;
• a host interface logic means for transferring data between the host memory and the host interface;
• the disk drive comprising:
• a head disk assembly;
• a media controller;
• the head disk assembly comprising:
• a disk;
• a spindle motor for rapidly rotating the disk;
• the disk being formatted to define a plurality of discrete radial positions at which data is recorded in a data track;
• each data track being formatted to define a plurality of equally spaced-apart servo sectors, each servo sector defining a wedge relative to an index;
• each data track being formatted to define a plurality of data sectors having sync marks, each sync mark defining a discrete circumferential position between the servo sectors;
• the media controller comprising;
• a servo system for controllably positioning the transducer head over a cylinder rotating under the head;
• a means for determining the position status variables;
• the position status variables comprising:
• the discrete radial position currently passing under the head the wedge currently passing under the head;
• a means for storing the position status variables;
• and
• a means for providing the stored position status variables to the host computer.

A method of optimizing data transfer commands sent to a disk drive in a computer system comprising a host having a host memory and a disk drive, the method comprising the steps of:

• storing disk drive formatting information in the host memory;
• storing disk drive performance parameters in the host memory;
• shadowing rotational and radial position information in the disk drive;
• periodically updating a portion of the host memory to store the shadowed rotational and radial position information;
• and while periodically updating the portion of host memory:
• storing a queue of disk drive data transfer commands in the host memory;
• scanning the queue of disk drive data transfer commands and calculating a next disk drive data transfer command to execute from the queue of disk drive data transfer commands based on the updated shadowed rotational and radial position information and the disk drive performance parameters;
• and
• transmitting the next disk drive data transfer command to the disk drive.

A method of optimizing data transfer commands sent to an array of disk drives in a computer system comprising a host having a host memory and a plurality of disk drives, the method comprising the steps of:

• storing formatting information for each of the plurality of disk drives in the host memory;
• storing disk drive performance parameters for each of the plurality of disk drives in the host memory;
• shadowing rotational and radial position information in each disk drive;
• periodically updating a portion of the host memory to store the shadowed rotational and radial position information for each disk drive;
• and while periodically updating the portion of host memory:
• storing a queue of disk drive data transfer commands which can be applied to any of the plurality of disk drives in the host memory;
• selecting a next data transfer command from the queue of disk drive data transfer commands;
• selecting a one of the plurality disk drives to receive the next data transfer command based on the updated shadowed rotational and radial position information and the disk drive performance parameters;
• and
• transmitting the next disk drive data transfer command to the selected disk drive.

A disk drive connectable to a host computer via a host interface for receiving data transfer commands and for communicating position status variables in the disk drive, the disk drive comprising:

• a head disk assembly;
• a media controller;
• the head disk assembly comprising:
• a disk;
• a spindle motor for rapidly rotating the disk;
• the disk being formatted to define a plurality of discrete radial positions at which data is recorded in a data track;
• each data track being formatted to define a plurality of equally spaced-apart servo sectors, each servo sector defining a wedge relative to an index;
• each data track being formatted to define a plurality of data sectors having sync marks, each sync mark defining a discrete circumferential position between the servo sectors;
• the media controller comprising;
• a servo system for controllably positioning the transducer head over a cylinder rotating under the head;
• a means for determining the position status variables;
• the position status variables comprising:
• the discrete radial position currently passing under the head the wedge currently passing under the head;
• a means for storing the position status variables;
• and
• a means for providing the stored position status variables to the host computer;
• whereby the host computer can be informed of the position status variables for optimizing the data transfer commands, wherein optimizing the data transfer commands comprises ordering the data transfer commands to the disk drive based on the position status variables.

A disk drive connectable to a host computer via a host interface for receiving data transfer commands and for communicating position status variables in the disk drive, the disk drive comprising:

• a head disk assembly;
• a media controller;
• the head disk assembly comprising:
• a disk;
• a spindle motor for rapidly rotating the disk;
• the disk being formatted to define a plurality of discrete radial positions at which data is recorded in a data track;
• each data track being formatted to define a plurality of equally spaced-apart servo sectors, each servo sector defining a wedge relative to an index;
• each data track being formatted to define a plurality of data sectors having sync marks, each sync mark defining a discrete circumferential position between the servo sectors;
• the media controller comprising;
• a servo system for controllably positioning the transducer head over a cylinder rotating under the head;
• a means for determining the position status variables;
• the position status variables comprising:
• the discrete radial position currently passing under the head the wedge currently passing under the head;
• a means for storing the position status variables;
• and
• a means for providing the stored position status variables to the host computer;
• whereby the host computer can be informed of the position status variables for optimizing the data transfer commands, wherein optimizing the data transfer commands comprises sequencing the data transfer commands to the disk drive to minimize mechanical latency of the disk drive.

A computer system comprising:

• a host computer for providing data transfer commands;
• a disk drive for receiving the data transfer commands and for providing data to the host;
• a host interface for connecting the host computer to the disk drive;
• the host computer comprising:
• a host memory;
• a host interface logic means for transferring data between the host memory and the host interface;
• the disk drive comprising:
• a head disk assembly;
• a media controller;
• the head disk assembly comprising:
• a disk;
• a spindle motor for rapidly rotating the disk;
• the disk being formatted to define a plurality of discrete radial positions at which data is recorded in a data track;
• each data track being formatted to define a plurality of equally spaced-apart servo sectors, each servo sector defining a wedge relative to an index;
• each data track being formatted to define a plurality of data sectors having sync marks, each sync mark defining a discrete circumferential position between the servo sectors;
• the media controller comprising;
• a servo system for controllably positioning the transducer head over a cylinder rotating under the head;
• a means for determining the position status variables;
• the position status variables comprising:
• the discrete radial position currently passing under the head the wedge currently passing under the head;
• a means for storing the position status variables;
• and
• a means for providing the stored position status variables to the host computer, wherein the host computer optimizes an order of the data transfer commands provided to the disk drive based on the position status variables.

A computer system comprising:

• a host computer for providing data transfer commands;
• a disk drive for receiving the data transfer commands and for providing data to the host;
• a host interface for connecting the host computer to the disk drive;
• the host computer comprising:
• a host memory;
• a host interface logic means for transferring data between the host memory and the host interface;
• the disk drive comprising:
• a head disk assembly;
• a media controller;
• the head disk assembly comprising:
• a disk;
• a spindle motor for rapidly rotating the disk;
• the disk being formatted to define a plurality of discrete radial positions at which data is recorded in a data track;
• each data track being formatted to define a plurality of equally spaced-apart servo sectors, each servo sector defining a wedge relative to an index;
• each data track being formatted to define a plurality of data sectors having sync marks, each sync mark defining a discrete circumferential position between the servo sectors;
• the media controller comprising;
• a servo system for controllably positioning the transducer head over a cylinder rotating under the head;
• a means for determining the position status variables;
• the position status variables comprising:
• the discrete radial position currently passing under the head the wedge currently passing under the head;
• a means for storing the position status variables;
• and
• a means for providing the stored position status variables to the host computer, wherein the host computer optimizes a sequence of the data transfer commands provided to the disk drive to minimize mechanical latency of the disk drive.