Back to results
US 5,311,287 AGranted
Direct access storage device with head-disc dynamics monitor
AssigneeInternational Business Machines Corporation
InventorNabil M. Amer
Life of this patent
Estimating the term…
Abstract
An apparatus and method for direct measurement for head/disc interface dynamics in a head/disc assembly is described incorporating two light beams positioned to reflect off two surfaces, two position sensitive detectors for receiving reflected light beams, and a processor for determining the displacement of the surfaces. The processor may further include circuitry for determining the change of displacement as a function of time of the two surfaces and for correlating displacement signals and change of displacement signals with themselves or with other predetermined stored signals to provide an indication of the operating status of the head/disc assembly. The invention overcomes the problem of experiencing unexpected head crashes and of predicting timely preventive maintenance of the head/disc assembly.
Claims31
An apparatus for measurement of head/disk dynamics in a head/disc assembly comprising:
- first means for reflecting a first light beam from a first surface of said disc towards a first detector,
- second means for reflecting a second light beam from a second surface towards a second detector, said second surface having a fixed relationship with respect to said head,
- third means for generating a first signal indicative of the displacement of said disc,
- fourth means for generating a second signal indicative of the displacement of said head whereby the displacement of said head and disc are measured,
- a memory for storing displacement signals indicative of normal and abnormal operation selected from the group consisting of spin-up, spin-down, sit-down, lift-off, ding, crash, catastrophic crash, time and distance for take-off, and an estimate of head height, and
- fifth means for correlating said stored signals with said first and second signals to identify the normal and abnormal operation of said head/disc assembly.
3 more elements
An apparatus for measurement of head/disk dynamics in a head/disc assembly comprising:
- first means for reflecting a first light beam from a first surface of said disc towards a first detector,
- second means for reflecting a second light beam from a second surface towards a second detector, said second surface having a fixed relationship with respect to said head,
- third means for generating a first signal indicative of the displacement of said disc,
- fourth means for generating a second signal indicative of the displacement of said head whereby the displacement of said head and disc are measured,
- a memory for storing change of displacement signals as a function of change in time indicative of displacement velocity in normal and abnormal operation selected from the group consisting of spin-up, spin-down, sit-down, lift-off, a ding, a crash, a catastrophic crash, time and distance for take-off, and an estimate of head height,
- fifth means coupled to said first signal for generating a third signal indicative of the displacement velocity of said disc, and
- sixth means for correlating said stored signals with said third signal to identify the normal and abnormal operation of said head/disc assembly.
4 more elements
An for measurement of head/disk dynamics in a head/disc assembly comprising:
- first means for reflecting a first light beam from a first surface of said disc towards a first detector,
- second means for reflecting a second light beam from a second surface towards a second detector, said second surface having a fixed relationship with respect to said head,
- third means for generating a first signal indicative of the displacement of said disc,
- fourth means for generating a second signal indicative of the displacement of said head whereby the displacement of said head and disc are measured,
- a memory for storing change of displacement signals as a function of change in time indicative of displacement velocity in normal and abnormal operation selected from the group consisting of spin-up, spin-down, sit-down, lift-off, a ding, a crash, a catastrophic crash, time and distance for take-off, and an estimate of head height,
- fifth means coupled to said first signal for generating a third signal indicative of the displacement velocity of said head, and
- sixth means for correlating said stored signals with said third signal to identify the normal and abnormal operation of said head/disc assembly.
4 more elements
An apparatus for indicating normal and abnormal operation of a head in a head/disc assembly comprising:
- first means for reflecting a first light beam from a first surface towards a first detector,
- said first surface having a fixed relationship with respect to said head,
- second means for generating a first signal indicative of the displacement of said head, and
- third means for performing auto-correlation on said first signal to provide a second signal indicative of normal and abnormal operation of said head at respective times.
1 more element
An apparatus for indicating normal operation of a head in a head disc assembly comprising:
- first means for reflecting a first light beam from a first surface towards a first detector,
- said first surface having a fixed relationship with respect to said head,
- second means for generating a first signal indicative of the displacement of said head,
- third means for storing signal representative of said first signal at times said head is operating normally in said head/disc assembly, and
- fourth means for cross-correlating said first signal with said second signal to provide a third signal indicative of normal operation of said head.
2 more elements
An apparatus for measurement of head/disk dynamics in a head/disc assembly comprising:
- first means for reflecting a first light beam from a first surface of said disc towards a first detector,
- second means for reflecting a second light beam from a second surface towards a second detector, said second surface having a fixed relationship with respect to said head,
- third means for generating a first signal indicative of the displacement of said disc,
- fourth means for generating a second signal indicative of the displacement of said head whereby the displacement of said head and disc are measured, and
- fifth means coupled to said third means for generating a third signal indicative of velocity of said disc transverse to its plane of intended of rotation.
2 more elements
A method for measurement of head/disc interface dynamics in a head/disc assembly comprising the steps of:
- first reflecting a first light beam from a first surface of said disc towards a first detector,
- second reflecting a second light beam from a second surface towards a second detector, said second surface having a fixed relationship with respect to said head,
- third generating a first signal indicative of the change of position of said disc,
- fourth generating a second signal indicative of the change of position of said head whereby the displacement of said head and disc are measured,
- storing displacement signals indicative of normal and abnormal operation selected from the group consisting of spin-up, spin-down, sit-down, lift-off, ding, crash, catastrophic crash, time and distance for take-off, and an estimate of head height, and
- correlating said stored signals with said first and second signals to identify the normal and abnormal operation of said head/disc assembly.
3 more elements
An apparatus for indicating normal operation of a disc in a head/disc assembly comprising:
- first means for reflecting a first light beam from a first surface of said disc towards a first detector,
- second means for generating a first signal indicative of the displacement of said disc,
- third means for generating a second signal indicative of the displacement of said disc during normal operation, and
- fourth means for correlating said first signal with said second signal.
1 more element
An apparatus for indicating abnormal operation of a disc in a head/disc assembly comprising:
- first means for reflecting a first light beam from a first surface of said disc towards a first detector,
- second means for generating a first signal indicative of the displacement of said disc, and
- third means for performing auto-correlation on said first signal to provide a second signal indicative of abnormal operation of said disc.
An apparatus for indicating normal operation of a disc in a head/disc assembly comprising:
- first means for reflecting a first light beam from a first surface of said disc towards a first detector,
- second means for generating a first signal indicative of the displacement of said disc,
- third means for storing a second signal representative of said first signal at times said disc is operating normally in said head/disc assembly, and
- fourth means for cross-correlating said first signal with said second signal to provide a third signal indicative of normal operation of said disc.
1 more element
An method for indicating normal operation of a disc in a head/disc assembly comprising the steps of:
- first reflecting a first light beam from a first surface of said disc towards a first detector,
- second generating a first signal indicative of the change of position of said disc,
- third generating a second signal indicative of said disc during normal operation, and
- fourth correlating said first signal with said second signal.
1 more element
A method for measurement of head/disc interface dynamics in a head/disc assembly comprising the steps of:
- first reflecting a first light beam from a first surface of said disc towards a first detector,
- second reflecting a second light beam from a second surface towards a second detector, said second surface having a fixed relationship with respect to said head,
- third generating a first signal indicative of the change of position of said disc,
- fourth generating a second signal indicative of the change of position of said head whereby the displacement of said head and disc are measured,
- storing change of displacement signals as a function of change in time indicative of displacement velocity in normal and abnormal operation selected from the group consisting of spin-up, spin-down, sit-down, lift-off, a ding, a crash, a catastrophic crash, time and distance for take-off, and an estimate of head height,
- generating a third signal indicative of the displacement velocity of said disc, and
- correlating said stored signals with said third signal to identify the normal and abnormal operation of said head/disc assembly.
4 more elements
A method for measurement of head/disc interface dynamics in a head/disc assembly comprising the steps of:
- first reflecting a first light beam from a first surface of said disc towards a first detector,
- second reflecting a second light beam from a second surface towards a second detector, said second surface having a fixed relationship with respect to said head,
- third generating a first signal indicative of the change of position of said disc,
- fourth generating a second signal indicative of the change of position of said head whereby the displacement of said head and disc are measured,
- storing change of displacement signals as a function of change in time indicative of displacement velocity in normal and abnormal operation selected from the group consisting of spin-up, spin-down, sit-down, lift-off, a ding, a crash, a catastrophic crash, time and distance for take-off, and an estimate of head height,
- generating a third signal indicative of the displacement velocity of said head, and
- correlating said stored signals with said third signal to identify the normal and abnormal operation of said head/disc assembly.
4 more elements
Dependencies are inferred from the claim text.