Full track profile derivative method for read and write width measurements of magnetic recording head
AssigneeHitachi Global Storage Technologies Netherlands B.V.
InventorsXiaodong Che, Terence Tin-Lok Lam, Zhong-heng Lin, Xiaoyu Sui
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Abstract
A method for measuring a magnetic read width MRW of a magnetic read sensor directly from the derivative of a full track profile, with better accuracy and more advantages than the micro-track method was invented and also there is no need to use a separate wide write head. The magnetic write width MWW of the write head, without the influence of sensor side reading, can also be obtained by this method along with the MRW with no additional calculations.
Claims18
A method for determining a magnetic read width (MRW) of a read head, comprising:
- recording a data track, having a full track profile;
- reading the full track profile of the data track;
- calculating the derivative of the full track profile (DF);
- selecting a first trial magnetic write width (MWWn);
- deriving two reader response functions R(x) from R(x)=DF(x)+R(x−MWWn) and R(x)=R(x+MWWn)−DF(x+MWWn) respectively;
- and
- determining a magnetic read width (MRW) from at least one of the reader response functions.
A method for determining a magnetic read width (MRW) of a read head, comprising:
- recording a data track, having a full track profile;
- reading the full track profile of the data track;
- calculating the derivative of the full track profile (DF);
- selecting a first trial magnetic write width (MWWn);
- deriving a reader response function R(x) from R(x)−R(x−3MWW)=DF(x)+DF(x−MWWn)+DF(x−2MWWn)=SumDF(x);
- and
- determining a magnetic read width MRW from the reader response function.
Dependencies are inferred from the claim text.