High capacity submicro-winchester fixed disk drive

• US 5,255,136 A
• Filed: 06/04/1991
• Issued: 10/19/1993
• Est. Priority Date: 08/17/1990
• Status: Expired due to Term

• Current Assignee: Maxtor Corporation (Seagate Technology Holdings Plc)
• Original Assignee: Quantum Corporation (Chi Ko Investment Co., Ltd.)
• Inventors: Tacklind, Thomas A., Moon, William G., Machado, Michael G., Barnard, Daniel E., Gold, Clifford M., Peterson, Bruce R., Do, James H., Moon, Ronald R.
• Primary Examiner(s): Callahan, Timothy P.
• Application Number:
  US07/710,171
• Time in Patent Office: 868 Days
• Field of Search: 360/77.02, 360/77.05, 360/77.08, 360/75
• US Class Current: 360/77.02
• CPC Class Codes: G11B 20/1833 by adding special lists or symbols to the coded information G11B20/1806, G11B20/1866 take precedence
• CPC Class Codes: G11B 5/59655 Sector, sample or burst servo format
• CPC Class Codes: H03M 13/151 using error location or error correction polynomials

Abstract

A miniature disk drive achieves storage densities of at least approximately 1700 tracks per inch per storage surface of a storage disk defining a series of radially extensive servo sectors embedded within circumferential zones of data tracks. The sectors are recorded at a constant data transfer rate while each zone has a data transfer rate adapted to disk radius. The drive includes a head and head positioner, a read preamplifier for amplifying analog signals read from, and for amplifying signals to be written to, a storage surface. A circuit board carries drive electronics including a read channel, a servo processing circuit for recovering head location information from the servo sectors, a data block sequencer for sequencing data blocks between a buffer and the storage surface, a buffer memory controller for controlling the buffer, a bus level interface circuit for transferring data blocks between the buffer and a host computer, and a programmed digital controller which functions within a head position servo loop and which also controls the sequencer, buffer controller and bus level interface circuit. As one feature, the servo sectors split data blocks into segments. Segment byte counts in each data block header are used by the sequencer automatically to assemble the segments into data blocks during read and to divide the blocks into segments during write. A single VLSI circuit including the sequencer, servo processing circuit, memory controller and an interface to the microcontroller is disclosed.

Claims

1. A Winchester disk drive data storage subsystem for connecting with a host computing system, the data storage subsystem including a head and disk assembly defining a disk spindle, a brushless DC spindle motor formed at said spindle for rotating a disk hub at a constant angular velocity, at least one rotating disk mounted to said hub and having two data storage surfaces defining a plurality of concentric data storage track locations having a track density of at least approximately 1700 tracks per inch, a data transducer head for each surface, the heads being radially positionable among the track locations, a mass balanced rotary voice coil actuated head positioning system for moving the data transducer heads between track locations during track seeking and settling and for maintaining a selected one of the data transducer heads in alignment with centerline of a track during track following operations during which data blocks are written to or read from the track being followed, the storage surfaces defining a series of radially extensive servo sectors embedded within circumferential zones of data tracks, the sectors being recorded at a constant data transfer rate and each sector including servo information comprising a track number value and a plurality of radially offset and circumferentially staggered servo bursts, each zone having a data transfer rate adapted to disk radius, and read preamplifier, write driver, head select integrated circuit means connected for selecting each said data transducer head, for amplifying analog signals read from a said data storage surface, and for amplifying signals to be written to said surface, the disk drive subsystem further comprising subsystem electronics mounted on a circuit board and including:

read channel means connected to said read preamplifier, write driver and head select integrated circuit means for processing said analog signals into digital signal transitions, and including pulse detector means for detecting said analog signals, phase locked loop means for generating a digital read data clock synchronized detected analog signals, and frequency synthesizer means for generating frequency signals for the phase locked loop means in relation to the data transfer rate of each data zone,

servo processing means connected to said read channel means for locating and processing said servo information located within each said servo sector into head position digital values,

data block sequencer means connected to said read channel means for locating and assembling data blocks from a serial data stream read from, and for forming and sending a serial data stream to, the data storage surfaces and for handling data block transfers between the disk storage surfaces and a buffer memory means,

buffer memory control means for handling transfers between the buffer memory means and a bus level interface means,

the bus level interface means for transferring data blocks and control values between the host computing system and the subsystem via a bus level interface structure,

the buffer memory means connected to said data block sequencer means and to said bus level interface means and controlled by said buffer memory control means for temporarily storing blocks of data passing between the subsystem and the host computing system, and

programmed digital controller means connected to said read channel means, said servo processing means, said data block sequencer means said buffer memory control means and said bus level interface means, and including servo supervision routine means for supervising operations of the servo processing means by generating and applying digital head position correction values to the head positioning system from said head position digital values generated by said servo processing means, and including data block transfer supervision routine means for supervising operations of said data block sequencer means, said buffer memory control means and said bus level interface means.

2. The Winchester disk drive data storage subsystem set forth in claim 1 wherein said subsystem comprises a single data storage disk having a diameter not substantially greater than 2.5 inches and capable of storing in excess of forty megabytes of formatted data on two data storage surfaces, and wherein the subsystem is included entirely within a form factor in a horizontal orientation of a height substantially not greater than 0.61 inch, a width substantially not greater than 2.76 inches, and a depth substantially not greater than 3.94 inches.

3. The Winchester disk drive data storage subsystem set forth in claim 1 wherein said subsystem comprises two data storage disks mounted in spaced apart relation on said hub, each disk having a diameter not substantially greater than 2.5 inches and capable of storing in excess of forty megabytes of formatted data on two data storage surfaces thereof having a track density, and wherein the subsystem is included entirely with a form factor in a horizontal orientation of a height substantially not greater than 0.75 inch, a width substantially not greater than 2.76 inches, and a depth substantially not greater than 3.94 inches.

4. The Winchester disk drive data storage subsystem set forth in claim 1 wherein a stator portion of said DC brushless spindle motor and a stator portion of said mass balanced rotary voice coil actuated head positioning system are formed integrally with a base of said head and disk assembly.

5. The Winchester disk drive data storage subsystem set forth in claim 1 wherein said data sequencer means codes said data stream into a three to two 1,7 RLL code for transfer to said data storage disk, and decodes said data stream from said data storage surface from said 1,7 RLL code to uncoded data.

6. The Winchester disk drive data storage subsystem set forth in claim 1 wherein said servo supervision routine means and said data block transfer supervision routine means are organized as modules such that modules directly relating to control of said bus level interface means may be replaced with modules directly relating to control of another type of bus level interface means, without need for replacing any other modules of said supervision routine means.

7. A submicro-Winchester disk drive data storage subsystem including a bus-level interface means for connecting with a host computing system, the data storage subsystem including a head and disk assembly including a disk spindle means and rotating hub and a brushless DC spindle motor formed at said spindle means and hub, at least one rotating disk mounted to said hub and having a diameter not substantially greater than 2.5 inches and capable of storing in excess of forty megabytes of formatted data on two data storage surfaces defining a plurality of concentric data storage track locations having a track density of at least approximately 1700 tracks per inch, a data transducer head for each surface, the heads being radially positionable among the track locations, a mass balanced rotary voice coil actuated head positioning system for moving the data transducer heads between track locations during track seeking and settling and for maintaining a selected one of the data transducer heads in alignment with centerline of a track during track following operations during which data blocks are written to or read from the track being followed, the storage surfaces defining a series of radially extensive servo sectors embedded within a plurality of circumferential zones of data tracks and prerecorded with track locating and track centering information, each zone having a data transfer rate adapted to disk radius, the servo sectors interrupting the data tracks at predetermined spaced apart circumferential locations across a data storage surface areas of the disk and thereby splitting at least some of the data blocks into segments, and read preamplifier, write driver, head select integrated circuit means connected for selecting each said data transducer head and for amplifying analog signals read from or to be written to a said data storage surface, the disk drive subsystem further comprising subsystem electronics mounted on a circuit board and including:

read channel means including pulse detector means, phase locked loop means and frequency synthesizer means for processing said analog signals into digital signal transitions,

servo processing means connected to said read channel means for locating and processing said track locating and track centering information located within each servo sector to provide head position digital values,

data block sequencer means for locating and assembling data blocks read from and written to the data storage surfaces as segments and for handling data block transfers between the disk storage surfaces and a buffer memory means,

buffer memory control means for handling transfers between the buffer memory means and the data block sequencer means, and between the buffer memory means and the bus level interface means,

said bus level interface means for transferring data blocks and control values between a host computing system and the subsystem via a bus level interface structure,

the buffer memory means connected to said data block sequencer means and to said bus level interface means for temporarily storing blocks of data passing between the subsystem and the host computing system, and

programmed digital controller means connected to said read channel means, said servo processing means, said data block sequencer means, said buffer memory control means and said bus level interface means and including servo supervision routing means for supervising operations of the servo processing means by generating and applying digital head position correction values to the head positioning system from said head position digital values generated by said servo processing means, and including data block transfer supervision routine means for supervising operations of said data block sequencer means, said buffer memory control means and said interface means.

8. The submicro-Winchester disk drive data storage subsystem set forth in claim 7 wherein each data block storage location defined on a said disk surface includes an ID field containing block segment counts indicative of the spatial arrangement of said block, and wherein said sequencer means is directly responsive to said block segment counts automatically to locate and assemble data blocks read from and written to the data storage surfaces.

9. The submicro-Winchester disk drive data storage subsystem set forth in claim 7 wherein said circuit board further includes spindle motor driver means for driving said brushless DC spindle motor.

10. The submicro-Winchester disk drive data storage subsystem set forth in claim 7 further including spindle motor driver means and spindle motor speed monitor means connected to said spindle motor driver means in order to monitor and regulate disk rotational speed at a predetermined constant angular velocity.

11. The submicro-Winchester disk drive data storage subsystem set forth in claim 7 further including single master clock means for generating and supplying clocking signals throughout said subsystem electronics.

12. The submicro-Winchester disk drive data storage subsystem set forth in claim 7 wherein each said servo sector includes a plurality of radially offset circumferentially sequential burst fields for providing track centerline information, and further including peak detector means selectively connected to a selected data transducer head through said read preamplifier, write driver and head select integrated circuit means during passes over said servo sector by said head, and wherein said microcontroller means comprises analog to digital conversion means for converting relative amplitude values obtained from reading said bursts into digital values.

13. The submicro-Winchester disk drive data storage subsystem set forth in claim 7 further including pulse width modulator means for putting out head position control signals as a series of variable duty cycle pulses, and further comprising low pass filter means and servo driver means connected in said head positioning system for receiving and filtering said variable duty cycle pulses and converting them into driving currents applied to said rotary actuator.

14. The submicro-Winchester disk drive data storage subsystem set forth in claim 7 wherein said microcontroller means includes an internal program memory means having some prestored control routines therein, and further comprising external program memory mean containing other prestored control routines.

29. The submicro-Winchester disk drive data storage subsystem set forth in claim 7 wherein said subsystem comprises a single data storage disk and is included entirely within a form factor including the circuit board in a horizontal orientation of a height substantially not greater than 0.61 inch, a width substantially not greater than 2.76 inches, and a depth substantially not greater than 3.94 inches.

30. The submicro-Winchester disk drive data storage subsystem set forth in claim 7 wherein said subsystem comprises two data storage disks mounted in spaced apart relation on said hub and is included entirely within a form factor including the circuit board in a horizontal orientation of a height substantially not greater than 0.75 inch, a width substantially not greater than 2.76 inches, and a depth substantially not greater than 3.94 inches.

15. A submicro-Winchester disk drive data host computing system including a bus-level interface means for connecting with a host computing system, the data storage system including a head and disk assembly including a disk spindle means having a rotating hub and brushless DC spindle motor means formed at said spindle means and hub, at least one rotating disk mounted to said hub and having a diameter not substantially greater than 2.5 inches and capable of storing in excess of forty megabytes of formatted data on two data storage surfaces each defining a plurality of concentric data storage track locations having a track density of at least approximately 1700 tracks per inch, a data transducer head for each surface, the heads being radially positionable among the track locations, a mass balanced rotary voice coil actuated head positioning system for moving the data transducer heads between track locations during track seeking and settling and for maintaining a selected one of the data transducer heads in alignment with centerline of a track during track following operations during which data blocks are written to or read from the track being followed, the storage surfaces defining a series of radially extensive servo sectors embedded within radially spaced apart circumferential zones of data tracks and prerecorded with track locating and track centering information at a constant data transfer rate, each zone having a data transfer rate adapted to disk radius, the servo sectors interrupting the data tracks at predetermined spaced apart circumferential locations across data storage surface areas of the disk and thereby splitting at least some of the data blocks into segments, each data block having a header field containing count byte information describing the lengths of the segments thereof, and read preamplifier-write driver-head select integrated circuit means connected for selecting each said data transducer head and for amplifying analog signals read from to be written to a said data storage surface, the disk drive subsystem further comprising subsystem electronics mounted on a circuit board and including:

first integrated circuit means connected to said read preamplifier-write driver-head select integrated circuit means and comprising read channel means including pulse detector means, phase locked loop means and frequency synthesizer means, for processing said analog signals into digital signal transitions,

second integrated circuit means connected to said first integrated circuit means and including;

servo processing means for locating and processing said track locating and track centering information located within each said servo sector into digital servo head position information,

data block sequencer means for locating and assembling data blocks read from and written to the data storage surface directly in response to the count byte information and for handling data block transfers between the disk storage surfaces and a buffer memory means,

buffer memory control means for handling transfers between the buffer memory means and the interface,

third integrated circuit means connected to said second integrated circuit means and including said bus level interface means for transferring data blocks and control values between the host computing system and the subsystem via a bus level interface arrangement,

the buffer memory means being connected to said second and third integrated circuit means for temporarily storing blocks of data passing between the subsystem and the host computing systems, and

programmed digital controller means connected to said first, second and third integrated circuit means via a control bus structure means, and including servo supervision routine means for supervising head positioning operations in response to the digital servo head position information processed by the servo processing means and in response to information received via the bus level interface means, and including data block transfer supervision routine means for supervising operations of said data block sequencer means, said buffer memory control means and said interface means.

16. The submicro-Winchester disk drive data storage subsystem set forth in claim 15 wherein said circuit board further includes spindle motor driver means for driving said brushless DC spindle motor, said spindle motor driver means being controlled by said programmed digital controller means.

17. The submicro-Winchester disk drive data storage subsystem set forth in claim 16 wherein said third integrated circuit means includes spindle motor speed monitor means connected to said spindle motor driver means for monitoring disk rotational speed and maintaining it at a predetermined constant angular velocity.

18. The submicro-Winchester disk drive data storage subsystem set forth in claim 15 wherein said third integrated circuit means further includes single master clock means for generating and supplying clocking signals to said second and fourth integrated circuit means and to said digital controller means.

19. The submicro-Winchester disk drive data storage subsystem set forth in claim 15 wherein the track centering information in each said servo sector comprises a plurality of radially offset circumferentially sequential burst fields for providing track centerline information, and wherein said first integrated circuit means further includes peak detector means selectively connected to a selected data transducer head through said read preamplifier-write driver-head select integrated circuit means during passes over said servo sector by said head, and wherein said digital controller means includes analog to digital conversion means for converting relative amplitude values obtained from reading said bursts into digital values.

20. The submicro-Winchester disk drive data storage subsystem set forth in claim 15 wherein said second integrated circuit means further includes pulse width modulator means for putting out head position control signals as a series of variable duty cycle pulses, and further comprising low pass filter means and servo driver means connected in said head positioning system for receiving and filtering said variable duty cycle pulses and converting them into driving currents applied to said rotary actuated head positioning system.

21. The submicro-Winchester disk drive data storage subsystem set forth in claim 15 wherein said digital controller means includes an internal program memory means having some prestored control routines therein, and further comprising external program memory means containing other prestored control routines.

22. The submicro-Winchester disk drive data storage subsystem set forth in claim 15 wherein said servo supervision routine means and said data block transfer supervision routine means are organized as modules such that modules directly relating to control of said bus level interface means may be replaced with modules directly relating to control of another type of bus level interface means, without need for replacing any other modules of said supervision routine means.

23. A monolithic very large scale (VLSI) integrated circuit for a disk drive data storage subsystem including a disk rotating at a controlled, substantially constant angular velocity and having data storage surfaces defining a series of radially extensive servo sectors embedded within radially spaced apart circumferential zones of data tracks and prerecorded with track locating and track centering information at a constant data transfer rate, each zone having a data transfer rate adapted to disk radius, the servo sectors interrupting the data tracks at predetermined spaced apart circumferential locations across data storage surface areas of the disk and thereby splitting at least some of the data blocks into segments, each data block having a header field containing count byte information describing the lengths of the segments thereof, a head for reading data from a said track and for writing data to a said track, the head being positioned by a head positioning mechanism operating from the digital head location and centering information within a digital head position servo loop including a programmed digital microcontroller, the subsystem further comprising read/write channel means extending between the integrated circuit and the head for processing analog signals comprising the data read by the head into a digital data stream, buffer memory means connected between the integrated circuit for temporary storage of data blocks in transit between storage locations on the disk and an interface circuit means, the interface circuit means for connecting the subsystem and the buffer memory means with a host computing system via a bus level interface, the monolithic VLSI integrated circuit comprising:

programmable data sequencer means for locating and automatically assembling data blocks from the digital data stream comprising said segments read from the disk in accordance with said count byte information, and for forming and sending to the read/write channel means a serial digital data stream of data blocks to be written in segments to the disk in accordance with said count byte information, at defined data block storage locations thereof,

memory controller means for generating and putting out addresses to the buffer memory means for enabling the buffer memory means to transfer data blocks to and from the sequencer means and to and from the interface circuit means,

digital servo decoder means for decoding said track locating information read by said head and for putting out digital head location values to said programmed microcontroller means, and

microcontroller interface means for enabling said programmed microcontroller means to have direct access to storage locations of said integrated circuit for storing control values for said data sequencer means, memory controller means and digital servo controller means.

24. The monolithic VLSI integrated circuit set forth in claim 23 wherein said information embedded in said servo sectors includes in one of said servo sectors a unique index pattern denoting a once-per-revolution index marker, and wherein said digital servo decoder means of said chip includes index pattern decoding means for decoding said unique index pattern into said index marker, and said chip further includes disk rotational speed monitoring and adjustment means responsive to means for sensing disk rotational velocity for generating speed up and slow down control signals for controlling a spindle motor driver circuit means.

25. The monolithic VLSI integrated circuit set forth in claim 23 further comprising pulse width modulator means controlled by said programmed microcontroller means for generating servo control pulses of controlled duration and applying said control pulses to a servo actuator driver circuit within said head positioner.

26. The monolithic VLSI integrated circuit set forth in claim 23 further comprising programmable master clock means for generating programmable clocking signals for controlling operation of said microcontroller means, said memory controller means and interface state machine means within said interface circuit means.

27. The monolithic VLSI integrated circuit set forth in claim 23 wherein said data sequencer means further comprises encoder/decoder means for encoding and decoding user data values into and from a predetermined zero run length limited code.

28. The monolithic VLSI integrated circuit set forth in claim 27 wherein the predetermined zero run length limited code comprises a 1,7 RLL code.