Information storage unit transducer positioning system

Claim 2

An arrangement for positioning a transducer at a desired one of a group of nominally parallel tracks on a record member which undergoes motion relative to the transducer, comprising: means including the transducer and a plurality of servo recordings along the tracks for generating at least one servo signal within a given time interval, the time of occurrence of the servo signal within the given time interval representing the location of the transducer relative to the various tracks of the group; means responsive to an indication of desired location of the transducer relative to the various tracks of the group for generating a control signal having changes in the value thereof within the given time interval, the time of occurrence of the changes in the value of the control signal within the given time interval representing the desired location of the transducer relative to the various tracks of the group; and means responsive to the servo and control signals for applying the servo signal to reposition the transducer relative to the tracks in a sense related to the value of the control signal upon generation of the servo signal to locate the desired one of the group of said tracks.

Claim 3

An arrangement according to claim 1, wherein the plurality of recordings along the tracks comprise a separate signal indicium within each of the tracks, the signal indicia being spatially staggered along the lengths of the tracks and each being operative to generate a servo signal within the transducer in response to movement of the transducer thereover.

Claim 4

An arrangement according to claim 1, wherein the control signal is a bilevel signal having two different values, and the means for applying the servo signal to reposition the transducer is operative to reposition the tRansducer relative to the tracks in one sense when the control signal is at a first level upon generation of the servo signal and in an opposite sense when the control signal is at a second level upon generation of the servo signal.

Claim 5

An arrangement according to claim 1, wherein the indication of desired location of the transducer comprises a coded binary address, and the means for generating a control signal includes means for decoding the coded binary address to provide a signal representing the desired location of the transducer.

Claim 6

An arrangement according to claim 1, wherein the means for generating at least one servo signal includes means for moving the transducer relative to the tracks during the given time interval, wherein the means for generating a control signal includes information storage means having a plurality of different positions, each of which is capable of storing a signal, means responsive to the indication of desired location of the transducer for entering a signal in a particular one of the positions of the information storage means representing the desired location of the transducer, means for cycling the stored signal through the various positions of the information storage means during the given time interval, and means coupled to each of the positions of the information storage means for providing the control signal with a first value when the signal is stored in selected ones of the positions of the information storage means and for providing the control signal with a second value when the signal is stored in other than the selected ones of the positions of the information storage means, and wherein the means for applying the servo signal to reposition the transducer includes first and second signal storage means coupled to receive servo signals from the transducer during the given time interval, gating means coupled to the first and second signal storage means and responsive to the control signal for gating servo signals from the transducer to the first signal storage means when the control signal has the first value and for gating servo signals from the transducer to the second signal storage means when the control signal has the second value, and means coupled to the first and second signal storage means for moving the transducer in one direction relative to the tracks in response to servo signals stored in the first signal storage means and in an opposite direction relative to the tracks in response to servo signals stored in the second signal storage means.

Claim 7

An arrangement according to claim 5, wherein the information storage means comprises a shift register, the means for providing the control signal with first and second values comprises first and second logic gates, each being coupled to a different plurality of bit positions of the shift register, and the gating means comprise first and second gates, each coupled between the transducer and a different one of the first and second signal storage means, the first gate being operative to pass servo signals from the transducer to the first signal storage means when the control signal has the first value and the second gate being operative to pass servo signals from the transducer to the second signal storage means when the control signal has the second value.

Claim 8

An arrangement according to claim 6, wherein the means for applying the servo signal to reposition the transducer includes means coupled to the first and second signal storage means for determining the difference between the values of servo signals stored therein, and means for applying the determined difference to reposition the transducer at the end of the given time interval.

Claim 9

The invention as set forth in claim 1, further comprising a coarse positioning system for positioning the transducer proximate a track within the group of nominally parallel tracks.

Claim 10

In a random access memory system wherein a coarse positioning system causes a transducer coupled to a movable actuator to move proximate an addressed one of a plurality of tracks within a predetermined tolerance, the combination therewith of fine positioning means comprising: relative address means for providing a relative address defining the location of an addressed track with respect to a group of tracks; window generator means for providing a time varying gate in response to the relative address; means including the transducer for providing a servo signal relating to servo information sensed by the transducer; and junction means for providing an error signal in response to the time varying gate and the servo signal, the error signal being applied to the actuator to cause the transducer to move in a direction and at a velocity relative to the position of the transducer with respect to the addressed track.

Claim 11

In a random access memory system wherein a coarse positioning system causes a transducer coupled to a movable actuator to move proximate an addressed one of a plurality of tracks within a predetermined tolerance, the combination therewith of fine positioning means comprising: relative address means for providing a relative address defining the location of an addressed track with respect to a group of tracks; window generator means for providing a time varying gate in response to the relative address; means including the transducer for providing a servo signal relating to servo information sensed by the transducer; and junction means for providing an error signal in response to the time varying gate and the servo signal, the error signal being applied to the actuator to cause the transducer to move in a direction and at a velocity relative to the position of the transducer with respect to the addressed track.

Claim 12

The invention as set forth in claim 9 further comprising means responsive to the coarse positioning system and coupled to the fine positioning system for enabling the fine positioning system prior to inhibiting of the coarse positioning system.

Claim 13

The invention as set forth in claim 9, wherein the fine positioning means has a closed loop gain, and further comprising a threshold detector responsive to the junction means for providing an increased gain when the transducer is within a small predetermined distance from the addressed track.

Claim 14

The invention as set forth in claim 9, further comprising means coupled to the coarse positioning system for providing an indication related to the difference between an addressed track and a transducer position and means responsive to the indication for bypassing the coarse positioning system and enabling the fine positioning system when the indication is less than a particular level.

Claim 15

The invention as set forth in claim 9, wherein the window generator means includes shift register means having a plurality of storage locations corresponding to a plurality of tracks of a track group, said shift register means being coupled to receive the relative address, and logic means communicating with the shift register means to provide an output defining time intervals representing track positions on opposite sides of the relative address.

Claim 16

The invention as set forth in claim 13, wherein the relative address means includes decoding means, and means communicating least significant digits of the relative address to the decoding means, said decoding means providing a plurality of outputs corresponding to tracks of a track group and being energized with respect to the track of the relative address.

Claim 17

An arrangement for positioning a transducer at a desired location along an axis relative to a plurality of nominally parallel tracks on a record member which is movable in a generally transverse direction relative to the axis, the lengths of the tracks being divided into plural data blades having servo blades interspaced therebetween, comprising: a servo signal indicium recorded in each track within a servo block, the servo signal indicia within each servo block being staggered so as to successively pass the axis as the record member undergoes motion relative to the axis; means for providing a servo signal related to servo signal indicia sensed by the transducer; means providing a binary number representing a desired one of the tracks at which the transducer is to be located; register means having a plurality of stages; decoder means responsive to the binary number for entering data in a selected one of the stages of the register representing the desired one of the tracks each time a servo block begins to pass the axis; means for circulating the entered data through the register means which the servo block passes the axis; logic means coupled to each of the stages of the register means for providing one UP signal when the entered data is in selected ones of the register stages and a DOWN signal when the entered data is in other than the selected ones of the register stages; and means coupled to the servo signal providing means and the logic means for moving the transducer in one direction along the axis in response to each servo signal indicium received by the separating means when the UP signal is present and for moving the transducer in an opposite direction along the axis in response to each servo signal indicium received by the servo signal providing means when the DOWN signal is present.

Claim 18

An arrangement for positioning a transducer at a desired location along an axis relative to a plurality of nominally parallel tracks on a record member which is movable in a generally transverse direction relative to the axis, the lengths of the tracks being divided into plural data blades having servo blades interspaced therebetween, comprising: a servo signal indicium recorded in each track within a servo block, the servo signal indicia within each servo block being staggered so as to successively pass the axis as the record member undergoes motion relative to the axis; means for providing a servo signal related to servo signal indicia sensed by the transducer; means providing a binary number representing a desired one of the tracks at which the transducer is to be located; register means having a plurality of stages; decoder means responsive to the binary number for entering data in a selected one of the stages of the register representing the desired one of the tracks each time a servo block begins to pass the axis; means for circulating the entered data through the register means which the servo block passes the axis; logic means coupled to each of the stages of the register means for providing one UP signal when the entered data is in selected ones of the register stages and a DOWN signal when the entered data is in other than the selected ones of the register stages; and means coupled to the servo signal providing means and the logic means for moving the transducer in one direction along the axis in response to each servo signal indicium received by the separating means when the UP signal is present and for moving the transducer in an opposite direction along the axis in response to each servo signal indicium received by the servo signal providing means when the DOWN signal is present.

Claim 19

An arrangement in accordance with claim 15, wherein the servo signal indicium recorded in each track comprises a change in the polarity of magnetic flux.

Claim 20

An arrangement in accordance with claim 15, wherein the logic means comprises first and second OR circuits, the first OR circuit being coupled to the selected ones of the register stages to provide the UP signal and the second OR circuit being coupled to the other than the selected ones of the register stages to provide the DOWN signal.

Claim 21

An arrangement in accordance with claim 15, wherein the means for moving the transducer includes first and second capacitors, first and second switches respectively coupling the first and second capacitors to receive and store the servo signal indicia from the separating means when turned on, the first and second switches being respectively turned on by the UP and DOWN signals, means coupled to the first and second capacitors for determining the difference between the values of signal indicia stored in the first and second capacitors, and means coupled between the means for determining the difference and the first and second capacitors for preventing discharge of the capacitors except upon command.

Claim 22

A random access storage system comprising: a rotatably mounted storage medium; transducer means disposed adjacent the storage medium; a reciprocating actuator coupled to move the transducer means relative to the storage medium; coarse positioning means coupled to the transducer means and the actuator for accessing the transducer means to the storage medium within a predetermined tolerance; servo information and data information interspersed along nominal track lines on the storage medium, the servo information comprising a plurality of groups of staggered magnetized pattern areas defining corresponding groups of nominal track lines; means coupled to the transducer means providing a servo signal; and fine positioning means coupled to the data separation means and the actuator for generating a signal precisely positioning the transducer means with respect to an addressed track, said fine positioning means comprising means defining a relative address corresponding to the addressed track, window generating means responsive to the relative address for controlling the gating of servo information from the servo signal providing means, and junction means responsive to the servo information from the servo signal providing means and the window generating means for generating a signal causing the transducer means to move with a direction and velocity corresponding to a position sensed by the transducer means and the relative address.

Claim 23

A random access storage system comprising: a rotatably mounted storage medium; transducer means disposed adjacent the storage medium; a reciprocating actuator coupled to move the transducer means relative to the storage medium; coarse positioning means coupled to the transducer means and the actuator for accessing the transducer means to the storage medium within a predetermined tolerance; servo information and data information interspersed along nominal track lines on the storage medium, the servo information comprising a plurality of groups of staggered magnetized pattern areas defining corresponding groups of nominal track lines; means coupled to the transducer means providing a servo signal; and fine positioning means coupled to the data separation means and the actuator for generating a signal precisely positioning the transducer means with respect to an addressed track, said fine positioning means comprising means defining a relative address corresponding to the addressed track, window generating means responsive to the relative address for controlling the gating of servo information from the servo signal providing means, and junction means responsive to the servo information from the servo signal providing means and the window generating means for generating a signal causing the transducer means to move with a direction and velocity corresponding to a position sensed by the transducer means and the relative address.

Claim 24

The invention as set forth in claim 19, wherein the coarse positioning means includes reticle transducer means for generating a signal having a frequency bearing a relationship to travel of the transducer means, the window generating means includes a shift register for cycling a plurality of data bits corresponding to one of a plurality of tracks in a track group, and logic means communicating with the shift register and providing an output bearing a relationship to the state of the bits of the shift register and elapsed time with respect to a time slot defined by the relative address, and the junction means includes first capacitor means and second capacitor means for storing signals received at the junction means during different time intervals of a servo sector and difference means providing a signal related to the difference in magnitudes of signals stored by the fIrst capacitor means and the second capacitor means.

Claim 25

A data storage member having pre-recorded servo information thereon defining nominal data track lines, said servo information extending along portions of the data track lines separated by other portions of the track lines which define data storage locations, said servo information comprising groups of staggered information records disposed about the nominal track lines of corresponding data track groups, and reference means defining a common time base for each data track group.

Claim 26

A data storage member having pre-recorded servo information thereon defining nominal data track lines, said servo information extending along portions of the data track lines separated by other portions of the track lines which define data storage locations, said servo information comprising groups of staggered information records disposed about the nominal track lines of corresponding data track groups, and reference means defining a common time base for each data track group.

Claim 27

A data storage member according to claim 21, wherein the member comprises a disc having a magnetizable surface on which the servo information is recorded, the groups of staggered information records comprising flux reversals defining magnetized pattern areas.