Abstract: Tilt between a head stack and its associated disk stack in a hard disk drive (HDD) is measured by determining the deviation of a target head from its expected position (based on the position of the current head) each time electrical contact is switched from the current head to a target head. A running average tilt value is stored and used to modify the logical seek distance used in a Rotational Position Optimization (RPO) algorithm to better order I/O requests in a queue. Also, the running average tilt value can be used by the servo to pre-position the target head before electrical contact is made with the target head, to improve speed of operation.

Abstract: Tilt between a head stack and its associated disk stack in a hard disk drive (HDD) is measured by determining the deviation of a target head from its expected position (based on the position of the current head) each time electrical contact is switched from the current head to a target head. A running average tilt value is stored and used to modify the logical seek distance used in a Rotational Position Optimization (RPO) algorithm to better order I/O requests in a queue. Also, the running average tilt value can be used by the servo to pre-position the target head before electrical contact is made with the target head, to improve speed of operation.

Abstract: A generic manufacturer-independent method to produce a metric of hard disk drive performance includes executing accesses from a reference sector on disk to several equidistantally-spaced target sectors, and recording the times of the accesses. These times are then ordered and used to generate shortest access times along with probabilities of achieving those access times, losing a disk revolution while accessing the target sector, and losing a disk revolution while executing a read/write operation.

Abstract: Tilt between a head stack and its associated disk stack in a hard disk drive (HDD) is measured by determining the deviation of a target head from its expected position (based on the position of the current head) each time electrical contact is switched from the current head to a target head. A running average tilt value is stored and used to modify the logical seek distance used in a Rotational Position Optimization (RPO) algorithm to better order I/O requests in a queue. Also, the running average tilt value can be used by the servo to pre-position the target head before electrical contact is made with the target head, to improve speed of operation.

Abstract: The invention provides a method of culturing cells. The method generally includes live stages: (1) expansion of ES cells; (2) generation of embryoid bodies; (3) selection of CNS precursor cells; (4) expansion of CNS precursor cells; and (5) differentiation of CNS precursor cells. During the expansion phase, the CNS precursor cells are cultured in a media which includes at least one neurologic agent such as bFGF, SHH, and FGF-8. The expanded CNS precursors are differentiated by withdrawal of at least one neurologic agent, typically, bFGF. Preferably, the differentiation media includes ascorbic acid. The method of the invention can be used to culture a variety of cells, preferably neuronal cells, including, but not limited to dopaminergic neuron cells, cholinergic neuronal cells and serotonergic neuron cells.

Abstract: A method and apparatus for compression and decompression of information, such as groups of computer program instructions, encodes (compresses) information comprising a plurality of units by receiving the information to be encoded, splitting the information into a plurality of subsets, each subset comprising a plurality of symbols, each symbol comprising at least a portion of a unit of information, and assigning a codeword to each symbol, for each subset. Preferably, the assignment is performed by determining the frequency of occurrence of each symbol, for each subset, and assigning a codeword to each symbol, based on the frequency of occurrence of each symbol, for each subset. In order to decode (decompress) encoded information, the information comprising a plurality of codewords, each codeword is decoded to form a symbol, each symbol is grouped into one of a plurality of subsets and the plurality of subsets is merged to form decoded information.

Abstract: An apparatus and method for transparent on-the-fly decompression of the program instruction stream of a processor. Connected between a processor and a memory storing compressed information is a decompression device. The decompression device, receives a request from the processor for information, retrieves compressed information from the memory, decompresses the retrieved compressed information to form uncompressed information, and transmits the uncompressed information to the processor. The compressed information may include both program instructions and data. When the decompression device receives a request for information, which includes an unmodified address, from the processor, it generates an index offset from the received unmodified address. An indexed address corresponding to the generated index offset is retrieved from an index table. Compressed information corresponding to the selected indexed address is retrieved from the memory and transmitted to the processor.

Abstract: A method for compressing a set of microcode to be utilized within a data processing system is disclosed. In accordance with the method and system of the present invention, a set of compiled microcode is parsed into multiple microcode segments, wherein each of these microcode segments is of equal length. Each of the microcode segments is then individually compressed by utilizing a data-compression routine. Next, all of these compressed microcode segments are concatenated to yield a set of compressed executable microcode. Finally, the starting address for each of the compressed microcode segments is stored in an indexer. By so doing, the required memory for storing the compressed executable microcode is reduced.