Storage apparatus and method for processing recording compensation

1. A storage apparatus comprising:

a storage for storing a plurality of compensation values in association with a plurality of bit sequence patterns, respectively, the compensation values each obtained by adding or subtracting a difference between recording compensation values of opposite polarities corresponding to a pattern causing nonlinearity to or from an average value of recording compensation values corresponding to the pattern causing nonlinearity;

a head for writing data into a medium; and

a controller for controlling the apparatus and driving the head, the controller determining whether to use one of the compensation values to drive the head to write an instantaneous data bit in dependence upon the immediate preceding data bits in reference to the bit sequence patterns.

2. The storage apparatus of claim 1 , wherein the controller changes data bit length on the basis of the one of the compensation values when writing the instantaneous data bit.

3. The storage apparatus of claim 2 , wherein the storage stores signed NRZI patterns in association with the compensation value.

4. The storage apparatus of claim 3 , wherein the controller compensates the data with the signed NRZI pattern.

5. A controller for controlling a head for writing data into a medium, comprising:

a storage for storing a plurality of compensation values in association with a plurality of bit sequence patterns, the compensation values each obtained by adding or subtracting a difference between recording compensation values of opposite polarities corresponding to a pattern causing nonlinearity to or from an average value of recording compensation values corresponding to the pattern causing nonlinearity; and

a compensation unit for determining whether to use one of the compensation values to drive the head to write an instantaneous data bit independence upon the immediate preceding data bits in reference to the bit sequence patterns.

6. The controller of claim 5 , wherein the compensation unit changes data bit length on the basis of the one of the compensation values when writing the instantaneous data bit.

7. The controller of claim 6 , wherein the storage stores signed NRZI patterns in association with the compensation value.

8. The controller of claim 7 , wherein the compensation unit compensates the data with the signed NRZI pattern.

9. A method of controlling apparatus having a medium for storing data and a head for writing data into the medium, comprising:

storing a plurality of compensation values in association with a plurality of bit sequence patterns, the compensation values each obtained by adding or subtracting a difference between recording compensation values of opposite polarities corresponding to a pattern causing nonlinearity to or from an average value of recording compensation values corresponding to the pattern causing nonlinearity; and

determining whether to use one of the compensation values to drive the head to write an instantaneous data bit in dependence upon the immediate preceding data bits in reference to the bit sequence patterns.

10. The method of claim 9 , further comprising changing data bit length on the basis of the one of the compensation values when writing the instantaneous data bit.

11. The method of claim 10 , wherein the storing stores signed NRZI patterns in association with the compensation value.

12. The method of claim 11 , wherein the compensating compensates the data with the signed NRZI pattern.