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, characterised in that said method comprises the steps of: (a) writing a first and second continuum of tracks (91,92) 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 (91) 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 (93) greater than N in number, a second series of tracks (94) containing said data, and a third series of blanking tracks (95), the operation of writing said block involving the steps of reading said first continuum (91) 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 (91) by up to P tracks, said third series of tracks (95) 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, characterised in that said method comprises the steps of: (a) writing a first and second continuum of tracks (91,92) 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 (91) 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 (93) greater than N in number, a second series of tracks (94) containing said data, and a third series of blanking tracks (95), the operation of writing said block involving the steps of reading said first continuum (91) 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 (91) by up to P tracks, said third series of tracks (95) 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 10

A method of storing data on recording tape in which a helical scan technique is employed to write to the tape in oblique tracks each including a main area for storing user data and at least one sub area for storing auxiliary information relating to said user data, characterised in that the method includes the step of writing tape usage data to a system area (82) of the tape at the end of each session of use of the tape, said tape usage data being written in a system block (100-102) made up of a predetermined number of tracks and said tape usage data being stored in its totality in the said at least one sub area (23) of each of a plurality of tracks whereby said information is recorded a plurality of times.

Claim 11

A method of storing data on recording tape in which a helical scan technique is employed to write to the tape in oblique tracks each including a main area for storing user data and at least one sub area for storing auxiliary information relating to said user data, characterised in that the method includes the step of writing tape usage data to a system area (82) of the tape at the end of each session of use of the tape, said tape usage data being written in a system block (100-102) made up of a predetermined number of tracks and said tape usage data being stored in its totality in the said at least one sub area (23) of each of a plurality of tracks whereby said information is recorded a plurality of times.