摘要:
One embodiment provides a method of managing power in a computer system. A device of the computer system is operated at a selected power-state. The power consumption of the computer system is monitored. If the power consumption of the computer system is approaching or has exceeded a power cap selected for the computer system, then a request to reduce the power-state for the device is generated in response. The operating system is used to service the request to reduce the power-state according to the priority of the request. The reduced power state is forced out-of-band following the request to reduce the power-state if the request is not immediately serviceable by the operating system. Different approaches can be taken to force the reduced power state, using, for example, system management mode or a platform environment control interface.
摘要:
Disclosed is a computer implemented method, computer program product, and apparatus for determining a safe lower bound for a commonly powered data processing system. A power management module operates the data processing system using at least one nominal operating parameter during an exploration periodicity, with the at least one nominal operating parameter being clock speed. The power management module determines whether a calibration period is occurring. The power management module calibrates the data processing system up to a measurement interval duration expiration. The power management module may repeat operating the data processing system using the at least one nominal operating parameter.
摘要:
A method for decoding data in a data storage system includes generating an output bit stream; generating a first error corrected bit stream in dependence on the output bit stream; generating a second error corrected bit stream in dependence on the first error corrected bit stream; generating a checksum in dependence of the second error corrected bit stream; and, in the event that the checksum is indicative of errors in the second error corrected bit stream and the second error corrected bit stream comprises at least one correct interleave: supplying data indicative of locations of correct bits in the second error corrected bit stream; and, regenerating the first error corrected bit stream in dependence on the pinning data.
摘要:
Methods and apparatus are provided for controlling writing and reading of data in an array of A storage fields of a probe-based data storage device in which data is written to and read from the array of storage fields by a corresponding array of probes. One method provides error-tolerance by exploiting the inherent parallelism of the probe storage array. A user data block to be written to the A-field array is first coded to produce a plurality of C-byte codewords, such that r.C=k1A where r is the number of codewords and k1 is an integer greater than or equal to 1. A sub-blocks of k1 bytes are produced from the codewords by selecting successive bytes of each sub-block cyclically from the r codewords. The A sub-blocks are then written via respective probes to the corresponding storage fields of the storage field array.
摘要:
A method and apparatus for providing a read channel having combined parity and non-parity post processing is disclosed. A post-processor combines parity and non-parity post processing to make both parity and non-parity corrections so that error events that cannot be detected by parity may be corrected. Non-parity detectable error events are only kept for consideration if their likelihood is above a set threshold.
摘要:
Receivers, methods, and computer program products can be used to demodulate a data signal transmitted from a digital source, which has a network sampling rate that is synchronized with a network clock. In an illustrative embodiment, a receiver includes a two-stage interpolator that receives digital samples of the data signal as an input and produces an interpolated digital sample stream to be filtered by an adaptive fractionally spaced decision feedback equalizer. The digital samples received in the interpolator are synchronized with a local clock; however, the interpolated sample stream is synchronized with the network clock. A slicer generates symbols for the samples output from the decision feedback equalizer by comparing the samples with a reference signaling alphabet. The receiver can be used in a V.90 client modem to demodulate pulse code modulated (PCM) data transmitted as pulse amplitude modulated (PAM) signals from a digital network. In addition, the receiver is compatible with legacy analog modem front ends and transmitters. The two-stage interpolator allows the timing synchronization to be performed with extremely fine granularity, which can be useful in PCM modems that typically require relatively high signal to noise ratios.
摘要:
Digital impairments in a set of Pulse Code Modulation (PCM) signal levels that are received at a client modem from a server modem are identified by compressing the set of PCM signal levels into a signature. Digital impairments are determined based on the signature. In a preferred embodiment, the PCM signal levels are compressed into a signature by identifying clusters and/or skips in the set of PCM signal levels. In particular, when transmitting PCM signal levels from a server modem to a client modem over a connection that is subject to digital impairments such as Robbed Bit Signaling (RBS) and/or PAD digital impairments and quantization, some adjacent PCM signal levels may become identical or very close to one another. Moreover, other adjacent signal levels may have a difference that is at least approximately twice the difference of other levels. The former phenomenon is referred to as a “cluster” and the latter phenomenon is referred to as a “skip”. By identifying clusters and/or skips in the set of PCM signals that are received at the client modem from the server modem, a signature of the network connection may be obtained. Digital impairments including RBS and/or PAD may be identified using the signature.
摘要:
Described is a modulation encoder having a finite state machine for converting input bits into output bits in which the number of alternating output bits is limited to j+1 where j is a predefined maximum number of transitions in the output bits, and in which the number of like output bits is limited to k+1 where k is a predefined maximum number of non-transitions in the output bits. The modulation encoder may be employed in encoding apparatus for converting an input bit stream into an output bit stream. Such apparatus may comprise partitioning logic for partitioning the input bit stream into a first group of bits and a second group of bits. A plurality of the aforementioned modulation encoders may be connected to the partitioning logic for converting the first group of bits into coded output bits. Combining logic may be connected to the or each modulation encoder and the partitioning logic for combining the coded output bits and the second group of bits to generate the output bit stream. Counterpart modulation decoders and decoding apparatus are also described.
摘要:
Modems, methods, and computer program products provide a dual power mode capability in which a maximum power limit is determined for a received signal and, based on that determination, at least one modem operational parameter is adjusted and/or digital impairment learning (DIL) sequence is selected. Adjustments made to the operational parameters may allow a modem to operate in a high power mode to achieve a higher downstream data rate. The higher downstream data rate may be attributed to an improved SNR resulting from an increase in data transmission power. Moreover, the modem may also operate in a normal power mode where the operational parameters may be set to maximize the client modem receiver's dynamic range. By selecting the DIL sequence based on the power limit, a DIL signal containing symbols having power levels within the power limit may be selected.
摘要:
Modems, methods, and computer program products identify a signaling alphabet that is in variance with an ideal alphabet due to digital impairments and is used to decode received data symbols. In particular, a set of alphabet thresholds are established that correspond to the data symbols. The data symbols are received in an equalizer, which generates output symbols in response thereto. A collection of data symbols corresponding to a particular alphabet threshold are accumulated and an average value is computed, which is then used to replace the current value for the particular alphabet threshold to which the average value corresponds. Equalizer performance is enhanced as the improved accuracy of the alphabet thresholds results in better error information being fed back for adapting the equalizer filter coefficients.