Method of storing data on recording tape
First 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.
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Accused Products
Abstract
A method is disclosed for effecting update-in-place of data that has been recorded on tape in oblique tracks using a helical-scan recording technique. The data to be updated is recorded in a block of M tracks lying between first and second continuum each at least of N tracks where N is the worst-case number of tracks required to achieve head/track alignment. The block of M tracks comprises a first series of at least N tracks, a second series of tracks containing the data, and a third series of at least P tracks. When updating the data, the block is rewritten as a whole in a single continuum with the first track of the block being written within a distance of P tracks from the last track of the first continuum.
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Citations
8 Claims
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- 0, characterized in that said method comprises the steps of;
Specification