Abstract: The disclosure is related to pulse width modulating a power signal to a heat resistive element of a transducer. The power signal may be a power output signal of preamplifier. The power signal may be provided to a heat resistive element in a transducer that is operable to read data from or write data to a data storage medium. The pulse width modulated power signal can allow for controlling the heating of the heat resistive element based on a thermal time constant of the heat resistive element and based on adjustable components of the pulse width modulated power signal.

Abstract: A data word is error correction encoded to provide a worst case codeword without bit transitions between worst case codeword bits. A modulation bit is calculated as a function of the worst case codeword. The modulation bit has a bit polarity opposite a bit polarity of the worst case codeword bits. The worst case codeword bits are added with the modulation bit to form a modulated code word.

Abstract: In general, this disclosure describes read recovery techniques for data storage devices that use soft information associated with multiple read operations to detect data. Specifically, the read recovery techniques comprise computing soft information for each bit detected during a first read operation of a data storage medium, computing soft information for each bit detected during a second read operation of the data storage medium and averaging the soft information computed during the first and second read operations to determine the value of each of the bits.

Abstract: A data word is error correction encoded to provide a worst case codeword without bit transitions between worst case codeword bits. A modulation bit is calculated as a function of the worst case codeword. The modulation bit has a bit polarity opposite a bit polarity of the worst case codeword bits. The worst case codeword bits are added with the modulation bit to form a modulated code word.

Abstract: A method of tuning a bias parameter for a magnetoresistive head in a data storage system includes the step of identifying, from multiple possible bias parameter values, a smallest bias parameter value for the magnetoresistive head which both maintains a bit error rate above a predetermined threshold bit error rate, and which satisfies a second criteria. The method then includes the step of setting an operational bias parameter value for the magnetoresistive head to the identified smallest bias parameter value. Also disclosed are data storage systems, or controllers which are connectable to or included with data storage systems, configured to implement the methods.

Abstract: A method of tuning a bias parameter for a magnetoresistive head in a data storage system includes the step of identifying, from multiple possible bias parameter values, a smallest bias parameter value for the magnetoresistive head which both maintains a bit error rate above a predetermined threshold bit error rate, and which satisfies a second criteria. The method then includes the step of setting an operational bias parameter value for the magnetoresistive head to the identified smallest bias parameter value. Also disclosed are data storage systems, or controllers which are connectable to or included with data storage systems, configured to implement the methods.

Abstract: A kind of underground temperature and pressure measuring system for hot-exploiting oil well mainly comprises a casing, a high-temperature sealing element, a high-temperature time-controlling unit, a pressure sensing unit and its recording system and a temperature sensing unit and its recording system, wherein, the high-temperature sealing element is made of flexible graphite, and the pressure sensing element is made of particular material; the temperature sensing unit is connected with the pressure sensing unit by bellows, so that the temperature sensing unit and its recording system can be put around the pressure sensing unit and its recording system, and therefore the present device is not long, but it can be used to measure temperature and pressure of underground steam at different depth simultaneously, which make the calculation of underground thermal conditions possible and reliable.