Abstract: Signals indicative of unencoded input data are encoded into a plurality of encoded sequences. A first subset of the plurality of encoded sequences are encoded according to a k constrained code of rate x/y and a second subset of the plurality of unencoded sequences are encoded according to a k constrained code of rate m/n wherein x/y≠m/n. The encoded sequences are transmitted to a partial response channel subject to noise. The encoded sequences are transmitted from the channel to a Viterbi detector having a trellis structure with a preselected, time-dependent pattern to create a time varying trellis structure for limiting a maximum length of parallel paths therethrough. The encoded sequences are detected with a Viterbi detector to provide detected, encoded sequences. The detected, encoded sequences are then decoded to provide an estimate of the input data.

Abstract: A light pattern modulator includes modulating means for modulating light instant thereon. The modulating means are mounted on at least two actuators which effect linear displacement in response to an electrical oscillating signal from input means. The mounting of the modulating means on the actuators enables movement of the modulating means effected by the actuators not to be physically constrained to movement about a fixed point or axis.

Abstract: A computer implemented method and system for switching from one application to a second application. A user enters a “switch to” command, either directly or imbedded within a macro. A determination is then made whether the application to be switched to is running. If the application is running, the focus of the operating system is switched to the second application. If the second application is not running, then the application is launched. When determining whether the application is running, determinations are made regarding whether the application is invisible or owned.

Abstract: A detector is used in detecting data encoded in a read signal received from a storage channel. The detector includes a Viterbi detector having a time-invariant structure configured to detect the data encoded according to a code having time varying constraints.

Abstract: First and second instances of a message are received over a wireless connection. It is determined whether the first and second instances of the message contain an error. If both instances contain an error, an error free instance of the message is reconstructed from the two erroneous instances by merging portions of the first and second instances.

Abstract: The present invention provides a method and apparatus for detecting data received from a magnetic storage channel having a channel pulse response represented by a polynomial including intersymbol interference (ISI) terms. The detector includes a Viterbi detector corresponding to a trellis structure having states connected by branches having associated branch metrics. In one embodiment, the Viterbi detector includes a branch metric calculator component configured to calculate a branch metric associated with each of the plurality of branches by removing a contribution to the branch metric associated with a predetermined ISI term.

Abstract: A method formats disc surfaces in a disc drive for storage of data in a group of tracks on the disc surfaces. The disc drive performs seek operations to seek among cylinders on the disc surfaces as a function of time according to an actual seek profile. An approximation of the actual seek profile is determined such that the actual seek profile falls within the approximation. The disc surfaces are formatted according to the approximation of the actual seek profile.

Abstract: An improved compressed file system is provided. In a preferred embodiment of the present invention, a memory cache is used for storing uncompressed data that is sent to or received from a compressed logical drive. When writing data to the compressed logical drive, the preferred embodiment of the present invention determines whether to use write-behind caching or write-through caching.