Apparatus for dead track recovery

Claim 2

Apparatus for recovery of missing data bits in reading static skew compensated parallel data tracks having at least two channels for parallel transmission of data bits, comprising the combination of first storage means for receiving said data bits from each of said channels and storing said received data bits therein, said first storage means responsive to a first periodic strobe signal for clearing said received data bits from said first storage means, second storage means responsive to a second periodic strobe signal for causing said second storage means to receive said data bits from the output of said first storage means, said second storage means responsive to a third periodic strobe signal for clearing said received data bits therefrom, means for detecting the absence of a necessary data bit in one of said parallel data bit channels at the ouput of said first storage means and generating a simulated data bit in response thereto, said generated data bit being applied as an input to said second storage means, switch means for receiving said simulated data bit from the output of said second storage means and selectively applying said simulated data bit to a known parallel data bit channel missing said necessary data bit, and clock generator means for generating said first, second and third periodic strobe signals, the periodic occurrence of which may be varied in functional relation to the average time interval between successive data characters in said parallel transmission channels.

Claim 3

The apparatus as described in claim 1, wherein said clock generator means comprises the combination of detecting means for detecting the occurrence of each of said data bits and generating an output pulse in response thereto, means responsive to said detecting means' output pulses for generating a plurality of first output signals in response to the receipt of the first data bit of a new data character, means responsive to said plurality of first output signals for generating a plurality of second output signals defining a variable periodic interval following the occurrence of said first data bit of a new data character detected, means responsive to said plurality of second output signals for generating a plurality of periodic strobe signals, the periodic occurrence of which is functionally related to the periodic interval of said plurality of second output signals, and control means responsive to said detecting means' output pulses and selected ones of said plurality of first and second output signals for controlling the periodic interval of said plurality of second output signals.

Claim 4

The apparatus as defined in claim 2, wherein said control means further comprises means for detecting the time relationship between selected ones of said first and second output signals generated in response to the occurrence of said first parallel data bit from one of the channels and generating a control signal in response thereto, and means for receiving successive ones of said control signals and averaging a predetermined number of said control signals for controlling the periodic interval of said plurality of second output signals.

Claim 5

The apparatus as defined in claim 1, wherein said means for detecting the absence of a necessary data bit comprises means for comparing the parity of said parallel data bit channels and generating a simulated data bit in response to detecting even parity.

Claim 6

The apparatus as defined in claim 1, wherein said static skew compensated parallel data tracks are created by a static skew compensation circuit having a master channel and one or more slave channels, and further comprising a dynamic visual indicator of the static skew delay of each slave channel relative to the delay of the master channel of said associated static skew compensation circuit.

Claim 7

Apparatus for recovering missing data bits in the parallel transmission of data having at least two channels for parallel transmission of data bits, comprising first storage means for receiving said data bits from each of said channels and storing said received data bits therein, said first storage means responsive to a periodic strobe signal for clearing said received data bits from said first storage means, second storage means for receiving said data bits from said first storage means and responsive to said periodic strobe signal for clearing said received data bits therefrom, means for detecting at the output of said first storage means the absence of a necessary bit in one of said parallel data bit channels for forming a data character and generating a simulated data bit in response thereto, third storage means for receiving said simulated data bit and responsive to said periodic strobe signal for clearing said simulated data bit therefrom, switch means for receiving said simulated data bit from the output of said third storage means and selectively applying said simulated data bit to a known parallel data bit channel missing said necessary data bit, and clock track means for generating said periodic strobe signal, the periodic occurrence of which is functionally related to the average time interval between successive data characters.

Claim 8

Apparatus for recovering missing data bits in the parallel transmission of data having at least two channels for parallel transmission of data bits, comprising first storage means for receiving said data bits from each of said channels and storing said received data bits therein, said first storage means responsive to a periodic strobe signal for clearing said received data bits from said first storage means, second storage means for receiving said data bits from said first storage means and responsive to said periodic strobe signal for clearing said received data bits therefrom, means for detecting at the output of said first storage means the absence of a necessary bit in one of said parallel data bit channels for forming a data character and generating a simulated data bit in response thereto, third storage means for receiving said simulated data bit and responsive to said periodic strobe signal for clearing said simulated data bit therefrom, switch means for receiving said simulated data bit from the output of said third storage means and selectively applying said simulated data bit to a known parallel data bit channel missing said necessary data bit, and clock track means for generating said periodic strobe signal, the periodic occurrence of which is functionally related to the average time interval between successive data characters.

Claim 9

The apparatus as defined in claim 6, wherein said clock track means comprises the combination of detecting means for detecting the occurrence of each of said data bits and generating an output pulse in response thereto, means responsive to said detecting means' output pulses for generating a plurality of first output signals in response to the receipt of the first data bit of a new data character, means responsive to said plurality of first output signals for generating a plurality of second output signals defining a variable periodic interval following the occurrence of said first data bit of a new data character, means responsive to said plurality of second output signals for generating a periodic strobe signal, the periodic occurrence of which is functionally related to the periodic interval of said plurality of second output signals, and control means responsive to said detecting means' output pulses and selected ones of said plurality of first and second output signals for controlling the periodic interval of said plurality of second output signals.

Claim 10

The apparatus as defined in claim 7, wherein said control means further includes means for detecting the occurrence of said detecting means' output pulses and selected ones of said first and second output signals generated in response to the occurrence of said first parallel data bit of a new data character and generating a control signal in response thereto, and means for receiving successive ones of said control signals and averaging a predetermined number of said control signals for controlling the periodic interval of said plurality of second output signals.

Claim 11

Apparatus for recovering missing data bits in a parallel data transmission system having at least two channels for static skew compensated parallel transmission of data bits, comprising the combination of first storage means for receiving said data bits from each of said channels and storing said received data bits therein, said first storage means reponsive to a first periodic strobe signal for clearing said received data bits from said first storage means, second storage means responsive to a second periodic strobe signal for receiving said data bits from the output of said first storage means, said second storage means responsive to a third strobe signal for clearing said received data bits therefrom, means for detecting at the output of said first storage means the absence of a necessary bit for forming a data character in one of said parallel data bit channels and generating a simulated data bit in response thereto, said generated data bit applied as an input to said second storage means, switch means for receiving said simulated data bit from the output of said second storage means and selectively applying said simulated data bit to a known parallel data bit channel missing said data bit, detecting means for detecting the occurrence of each of said data bits and generating an output pulse in response thereto, means responsive to said detecting means' output pulses for generating a plurality of first output signals in response to the receipt of the first data bit of a new data character, means reponsive to said plurality of first output signals for generating a plurality of second output signals defining a periodic interval following the occurrence of said first data bit of a new character, means responsive to said plurality of second output signals for generating said first, second and third periodic strobe signals, the periodic occurrence of each of which is functionally related to the periodic interval of said plurality of second output signals, and control means responsive to said detecting means' output pulses and selected ones of said plurality of first and second output signals for controlling the periodic interval of said plurality of second output signals.

Claim 12

Apparatus for recovering missing data bits in a parallel data transmission system having at least two channels for static skew compensated parallel transmission of data bits, comprising the combination of first storage means for receiving said data bits from each of said channels and storing said received data bits therein, said first storage means reponsive to a first periodic strobe signal for clearing said received data bits from said first storage means, second storage means responsive to a second periodic strobe signal for receiving said data bits from the output of said first storage means, said second storage means responsive to a third strobe signal for clearing said received data bits therefrom, means for detecting at the output of said first storage means the absence of a necessary bit for forming a data character in one of said parallel data bit channels and generating a simulated data bit in response thereto, said generated data bit applied as an input to said second storage means, switch means for receiving said simulated data bit from the output of said second storage means and selectively applying said simulated data bit to a known parallel data bit channel missing said data bit, detecting means for detecting the occurrence of each of said data bits and generating an output pulse in response thereto, means responsive to said detecting means' output pulses for generating a plurality of first output signals in response to the receipt of the first data bit of a new data character, means reponsive to said plurality of first output signals for generating a plurality of second output signals defining a periodic interval following the occurrence of said first data bit of a new character, means responsive to said plurality of second output signals for generating said first, second and third periodic strobe signals, the periodic occurrence of each of which is functionally related to the periodic interval of said plurality of second output signals, and control means responsive to said detecting means' output pulses and selected ones of said plurality of first and second output signals for controlling the periodic interval of said plurality of second output signals.

Claim 13

The apparatus as defined in claim 9, wherein said control means further comprises means for detecting the occurrence of said detecting means' output pulses and selected ones of said first and second output signals generated in response to the occurrence of said first data bit in a new data character and generating a control signal in response thereto, and means for receiving successive ones of said control signals and averaging a predetermined number of said control signals for controlling the periodic interval of said plurality of second output signals.

Claim 14

The apparatus as defined in claim 9, wherein said means for detecting the absence of a necessary data bit comprises means for comparing the parity of said parallel data bit channels and generating a simulated data bit in response to detecting even parity.

Claim 15

The apparatus as defined in claim 9, wherein said static skew compensated parallel data tracks are created by a static skew compensation circuit having a master channel and one or more slave channels, and further comprising dynamic indicator means for visually indicating the static skew delay of each slave channel relative to the master channel of said associated static skew compensation circuit.

Claim 16

Apparatus for recovery of missing information bits in static skew compensated magnetic recorded parallel data tracks having at least two channels for parallel transmission of data bits, comprising the combination of first storage means for receiving said data bits from each of said channels and storing said received data bits therein, said first storage means responsive to a periodic strobe signal for clearing said received data bits from said first storage means, second storage means for receiving said data bits from the output of said first storage means, said second storage means also responsive to a periodic strobe signal for clearing said received data bits therefrom, means for detecting at the output of said first storage means the absence of a necessary information bit in one of said parallel channels and generating a simulated information bit in response thereto, said generated information bit applied as an input to said second storage means, switch means for receiving said simulated information bit from the output of said second storage means and selectively applying said simulated information bit to a known parallel channel missing said bit, and clock means for generating said periodic strobe signals, the periodic occurrence of which may be varied in functional relation to the average time interval between selected successive magnetic flux changes on the recording channels.

Claim 17

Apparatus for recovery of missing information bits in static skew compensated magnetic recorded parallel data tracks having at least two channels for parallel transmission of data bits, comprising the combination of first storage means for receiving said data bits from each of said channels and storing said received data bits therein, said first storage means responsive to a periodic strobe signal for clearing said received data bits from said first storage means, second storage means for receiving said data bits from the output of said first storage means, said second storage means also responsive to a periodic strobe signal for clearing said received data bits therefrom, means for detecting at the output of said first storage means the absence of a necessary information bit in one of said parallel channels and generating a simulated information bit in response thereto, said generated information bit applied as an input to said second storage means, switch means for receiving said simulated information bit from the output of said second storage means and selectively applying said simulated information bit to a known parallel channel missing said bit, and clock means for generating said periodic strobe signals, the periodic occurrence of which may be varied in functional relation to the average time interval between selected successive magnetic flux changes on the recording channels.

Claim 18

The apparatus defined in claim 13, wherein said clock means further comprises means responsive to said selected successive magnetic flux changes for generating a plurality of output signals, selected ones of said signals defining a periodic interval following the occurrence of said selected magnetic flux changes, means responsive to said plurality of second output signals for generating periodic strobe signals, the periodic occurrence of each of which is functionally related to the periodic interval of said plurality of second output signals, and control means cooperating with said means responsive to said selected successive magnetic flux changes and selected ones of said plurality of output signals for controlling the periodic interval of said plurality of output signals.

Claim 19

The apparatus as defined in claim 14, wherein said means for generating periodic strobe pulses generates one periodic strobe signal which simultaneously clears said first and second storage means.

Claim 20

The apparatus as defined in claim 14, wherein said means for generating periodic strobe pulses generates a plurality of strobe signals, a first strobe signal clearing said first storage means, a second strobe signal enabling said second storage means to receive said data bits from said first storage means, and a third strobe signal clearing said second storage means.

Claim 21

The apparatus defined in claim 14, wherein said control means further comprises means for detecting the occurrence of said magnetic flux changes and selected ones of said output signals and generating a control signal in response thereto, and means for receiving successive ones of said control signals and averaging a predetermined number of said control signals for controlling the periodic interval of said selected ones of said plurality of output signals.

Claim 22

The apparatus as defined in claim 13, wherein said means for detecting the absence of a necessary information bit comprises means for comparing the parity of said parallel data bit channels and generating a simulated data bit in response to detecting even parity.

Claim 23

The apparatus as defined in claim 13, wherein said means for detecting the absence of a necessary information bit comprises means for detecting parity errors in a parity track of said parallel transmission channels and generating a correct parity bit in response thereto.

Claim 24

The apparatus as defined in claim 17, wherein said selected successive magnetic flux changes on the recording channels are successive data characters in said parallel transmission channels.

Claim 25

The apparatus as defined in claim 17, wherein said selected successive magnetic flux changes on the recording channels are successive clock signals on a separate clock track in said parallel transmission channels.

Claim 26

The apparatus as defined in claim 13, wherein said static skew compensated parallel data tracks are created by a static skew compensation circuit having a master channel and one or more slave channels, and furher comprising dynamic indicator means for visually indicating the static skew delay of each slave channel relative to the master channel of said associated static skew compensation circuit.