Method of storing data on recording tape

Claim 1

A method of storing data on a recording tape and of subsequently updating that data, said method employing helical scan recording in which data is written in oblique tracks and a head tracking alignment technique is used that enables tracking alignment to be achieved after a maximum number of N tracks where N>0, characterized in that said method comprises the steps of: (a) writing a first and a second continuum of tracks each containing more than N tracks in number and being separated from each other along the tape by a number of tracks Q, the last track of said first continuum being identifiable by data recorded in that continuum beyond the first N tracks thereof, (b) subsequently writing data to tape in a block of M tracks made up of a first series of tracks greater than N in number, a second series of tracks containing said data, and a third series of blanking tracks, the operation of writing said block involving the steps of reading said first continuum to identify the last track thereof, and writing said block as a continuum of tracks starting at a location positioned beyond said last track of the first continuum by up to P tracks, said third series of tracks being at least P in number, (c) repeating step (b) each time it is desired to update the data held in said block, the values of N and P being predetermined and the maximum value of M being set by the value of the quantity (Q-P), and step (a) being such that the inequality Q>(N+2P) is satisfied.

Claim 2

A method of storing data on a recording tape and of subsequently updating that data, said method employing helical scan recording in which data is written in oblique tracks and a head tracking alignment technique is used that enables tracking alignment to be achieved after a maximum number of N tracks where N>0, characterized in that said method comprises the steps of: (a) writing a first and a second continuum of tracks each containing more than N tracks in number and being separated from each other along the tape by a number of tracks Q, the last track of said first continuum being identifiable by data recorded in that continuum beyond the first N tracks thereof, (b) subsequently writing data to tape in a block of M tracks made up of a first series of tracks greater than N in number, a second series of tracks containing said data, and a third series of blanking tracks, the operation of writing said block involving the steps of reading said first continuum to identify the last track thereof, and writing said block as a continuum of tracks starting at a location positioned beyond said last track of the first continuum by up to P tracks, said third series of tracks being at least P in number, (c) repeating step (b) each time it is desired to update the data held in said block, the values of N and P being predetermined and the maximum value of M being set by the value of the quantity (Q-P), and step (a) being such that the inequality Q>(N+2P) is satisfied.