A method and an apparatus to control a data storage system, and more particularly, a method and an apparatus to restore the stability of a head in a data storage system by automatically applying a bias shock current to the head in accordance with the result of a thermal asperity detection (TAD) method, in case that a quality problem occurs in the manufacturing process and/or under severe user conditions. A thermal asperity detection (TAD) routine operates if BER is large or an ECC error occurs in a process of manufacturing a data storage system or in a user field. Thus, it is determined whether the instability of a head causes a quality problem, and if it is determined that the instability of the head causes the quality problem, a bias shock current is automatically applied to the head to restore the stability of the head. It is accurately determined whether the head is unstable if the data quality problem occurs in the process of manufacturing the data storage system or in the user field to automatically restore the stability of the head. As a result, the quality of the data storage system is improved in the manufacturing process thereof and in the market.
Techniques to test a wireless communication link using configurable channels and rates. A W-Markov test service may be invoked to test and/or verify the performance of the downlink and/or uplink using at least one transport channel for each link. Each transport channel may be individually configured. The W-Markov test service supports generation of test data based on a defined data sequence or a pseudo-random number generator. The testing may be performed based on a particular deterministic or pseudo-random activity model. For voice call testing, a first-order Markov model may be used to model voice activity and to select the rate to use for each transmission time interval (TTI). For Adaptive Multi-Rate (AMR), testing may be performed based on configurable AMR rates and silence descriptor (SID) types. The test data generation processes are synchronized between the transmitter and receiver. Bit, frame, and/or block error rates and other statistics may be collected.
