Updatable magnetic records

Claim 3

The method of claim 1 further including establishing a given minimum length as a quanta of record media and establishing all record lengths as an integral number of said quanta; and establishing erased portions between adjacent records.

Claim 4

The method set forth in claim 1 wherein said magnetic media is an elongated magnetic member and further including the steps of initially formatting the magnetic member with magnetic indicia spaced apart at predetermined intervals determined by said given lengths and subsequently recording said signals beginning in accordance with said indicia, and said given lengths extending in the same direction along said member whereby recording and readback of said signals are always indicated by said indicia.

Claim 5

The method set forth in claim 1 wherein said signals are digital signals in a plurality of tracks disposeD transverse to the direction of relative motion with a given number of digital signals being associated with a given length on said media in the direction of relative motion at a nominal velocity; said given length being determined by said given number of digital signals; and counting the displacement in terms of said digital signals and comparing the counted number of digital signals with a threshold for indicating excessive deviations in recording.

Claim 6

The method set forth in claim 4 further including using a tachometer associated with the driving means of the relative motion for establishing relative displacement indications, said driving means generating digital signals having a frequency substantially lower than the digital signals being recorded and defining quantum of media length for a given number of digital signals; and selecting an integral number of said digital signals and of said tachometer signals as a criteria for determining said given length.

Claim 7

The method set forth in claim 5 further including taking a media which has already been recorded in accordance with claim 5, establishing relationships between the recorded tape and a signal-handling circuit, and causing predetermined motion of said media with respect to a transducer as indicated by the tachometer, then re-recording signals on said media based upon the tachometer signals and the previously recorded signals whereby information content in a given record block is updated in place in accordance with the tachometer stabilizing the length of the data record on the media within limits of said given length in accordance with velocity variations of said media relative motion; and establishing padding areas within said given length in accordance with the difference between the data recording length and said given length whereby the effective record length on said media remains substantially constant during updating operations.

Claim 8

An updatable magnetic record member, including the combination: a plurality of record areas each of predetermined length in accordance with an expected maximum relative velocity of member transport for a given number of digital data signals recorded in each such record area; and each record area having a record portion of a length in accordance with a given velocity of recording less than said expected maximum velocity and any remaining portion being a padding area enabling selective changing of signals in said record area independent of other record areas.

Claim 9

An updatable magnetic record member, including the combination: a plurality of record areas each of predetermined length in accordance with an expected maximum relative velocity of member transport for a given number of digital data signals recorded in each such record area; and each record area having a record portion of a length in accordance with a given velocity of recording less than said expected maximum velocity and any remaining portion being a padding area enabling selective changing of signals in said record area independent of other record areas.

Claim 10

A magnetic recording system for recording digital data signals as a block of signals on a magnetic tape, a magnetic transducer, signal processing circuits for supplying signals to be recorded to said transducer; tape displacement sensing means generating signals indicating quanta of tape displacement; means indicating the number of digital data signals being recorded in a block of such signals; means in said signal processing circuits comparing said tape displacement indicating signals and said number indication for establishing a result number indicating a given length on said media for recording blocks of such data signals thereon in accordance with the maximum design velocity of any tape transport with which said tape is to be used; and means responsive to said result signal to establish said given length to be longer in the tape than the length required to record said indicated number of signals by a maximum tape velocity operating transport.

Claim 11

A magnetic recording system for recording digital data signals as a block of signals on a magnetic tape, a magnetic transducer, signal processing circuits for supplying signals to be recorded to said transducer; tape displacement sensing means generating signals indicating quanta of tape displacement; means indicating the number of digital data signals being recorded in a block of such signals; means in said signal processing circuits comparing said tape displacement indicating signals and said number indication for establishing a result number indicating a given length on said media for recording blocks of such data signals thereon in accordance with the maximum design velocity of any tape transport with which said tape is to be used; and means responsive to said result signal to establish said given length to be longer in the tape than the length required to record said indicated number of signals by a maximum tape velocity operating transport.

Claim 12

The recording system set forth in claim 8 further including means in said signal processing circuit for recording padding signals in a padding area between recorded digital data signals on the media and an end of said given length.

Claim 13

The recording system set forth in claim 9 further including compare means having threshold means responsive to a given count of displacement signals to signal an error condition.