Data Storage Institute

Thomas Yun Fook Liew

Jian-Ping Wang

Seng Ghee Tan

Udaya Ahangama W Silva

Lea Peng Tan

Teck Ee Loh

A method and apparatus are provided for efficiently testing magnetic media in which a read level test is performed using an approximation for an average signal level in determining a test threshold and while reading data and testing against the approximate average read signal level, the data signal level is averaged to determine the real average read signal and this value is then used to adjust the results of the comparisons performed against the approximate average read level.

Method and apparatus for high throughput media defect testing using true reference value

A method of analyzing defects in a magnetic thin film is provided. A magnetic field is applied to the magnetic thin film. The magnetization of the magnetic thin film is measured over a range of different field strengths. A value representative of a magnetic hardness coefficient is calculated for the magnetic thin film from the magnetizations measured. The calculated value is compared with a reference value. Defect information is determined in dependence upon the comparison made. The defect information determined may relate to: (a) the relative levels of defects, if the reference value is representative of the magnetic hardness coefficient of a control specimen having a predetermined defect level; (b) the predominant type of defects, if the reference value is representative of the magnetic hardness coefficient obtained when the magnetic field is applied in a different direction; and (c) the distribution of defects, if the magnetizations are measured for a selected part of the magnetic thin film and compared with a reference value which is representative of a magnetic hardness coefficient calculated from magnetizations measured for a part other than the selected part of the magnetic thin film.

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Singapore, Singapore

Thomas Yun Fook Liew