Adaptive redundance in data recording

Claim 1

Apparatus for assuredly recording source data in a magnetic medium having surface defects therein that are, statistically, no greater than a given length and which are, statistically, separated by more than a certain distance, said data being formatted in segments that, as recorded in said magnetic medium at a nominal recording speed, have lengths that are no greater than the length of said certain distance, each said segment being comprised of said data formatted in blocks thereof, each said data block being of a length, as recorded in said magnetic medium, that is at least as great as said given length, and each said segment, further, having at least two less data blocks per segment than said segment would otherwise be capable of containing, said apparatus comprising (a) magnetic head means, (b) means for producing a flag signal, (c) a first data processing path for processing said data, (d) a second data processing path for processing said data, said second data processing path having, in comparison to that of said first data processing path, means therein for delaying the feedthrough of data therein for a duration corresponding to the time between the start and end of at least two data blocks, (e) means for producing a write failure signal signifying whether data has been recorded within said magnetic medium, and (f) switching means cooperative with said means for producing a write failure signal (1) for applying the data of said first data processing path to said magnetic head means in the absence of a write failure signal and (2) for applying, in response to said write failure signal, said flag signal briefly to said magnetic head means, and thereafter applying the data of said second data processing path to said magnetic head means, whereby, during playback of the data so recorded in said magnetic medium, the format of the data processed by either or both said data processing paths may be reconstituted, said played-back flag signal serving to signify that the recorded data of the data block just preceding the played-back flag signal is defective, but that correct data may be found in the recorded block just following such flag signal.

Claim 19

The method of recording information in a magnetic medium having defects therein which are statistically no greater than a given length and which are each separated by a distance that is statistically no less than a certain distance comprising the steps of (a) arranging said information in blocks thereof which, when recorded in said medium at a nominal recording speed, are at least as long as said given length, (b) arranging said information blocks into information segments which, when recorded in said medium at said nominal recording speed, have lengths that are no greater than the length of said certain distance, each said information segment being comprised of at least two less information blocks than might be accommodated within said segment, thereby to provide at least two blocks-worth of segment which is vacant of information, (c) sensing during the recording of each given segment whether, in fact, recording has taken place, and (d) if recording has not taken place, immediately recording in said medium a flag signal and, thereafter, recording the information which failed to get recorded, utilizing therefor the vacant portions of said given information segment.

Claim 20

The method of recording information in a magnetic medium having defects therein which are statistically no greater than a given length and which are each separated by a distance that is statistically no less than a certain distance comprising the steps of (a) arranging said information in blocks thereof which, when recorded in said medium at a nominal recording speed, are at least as long as said given length, (b) arranging said information blocks into information segments which, when recorded in said medium at said nominal recording speed, have lengths that are no greater than the length of said certain distance, each said information segment being comprised of at least two less information blocks than might be accommodated within said segment, thereby to provide at least two blocks-worth of segment which is vacant of information, (c) sensing during the recording of each given segment whether, in fact, recording has taken place, and (d) if recording has not taken place, immediately recording in said medium a flag signal and, thereafter, recording the information which failed to get recorded, utilizing therefor the vacant portions of said given information segment.