Abstract: The present invention provides a method, apparatus and article of manufacture for selecting commands to execute from a command queue in a data storage device. The present invention reduces maximum service times under random queued workloads by executing the oldest command in the queue at a constant and predetermined rate. This yields a minimal yet predictable performance penalty, while significantly reducing maximum service times.

Abstract: A method and apparatus is provided which dynamically alters SDRAM memory interface timings to provide minimum read access latencies for different types of memory accesses in a memory subsystem of a computer system. The dynamic alteration of the SDRAM memory interface timings is based on workload and is determined with information from the memory controller read queue.

Abstract: A method and apparatus for estimating the flyheight of an airbearing slider in a storage device. The slider floats on an airbearing over a rotating storage disk. The storage disk includes a washboard-sequence having washboard-sections each comprising surface profile variations having a different pitch. The pitches are selected from within a range of values likely to excite an airbearing resonance of the slider as the storage disk rotates at a rated storage disk velocity. For each of the washboard-sections, a maximum amplitude of flyheight modulation of the slider resulting from the slider floating over that washboard-section is measured. A determination is made of which washboard-section caused the largest measured flyheight modulation. The washboard-section having a pitch that provides an excitation frequency (when the disk is rotated at the rated storage disk velocity) that is closest to the actual airbearing resonance frequency of the slider will produce the largest flyheight modulation.

Abstract: A recording disk contains at least two types of servo sector format, including a first type having a relatively larger track identifying field containing the track number, and a second type having an abbreviated track identifying field identifying a track within a range of tracks, the range being less than the full range of tracks on the disk surface. Preferably, Gray code encodings are used, the first type of track field contains sufficient Gray code bits to identify the ful track number, every Nth servo sector is of the first type, and all servo sectors in between are of the second type, N being at least 2. As a result, the disk area required for track identification is reduced, and the additional disk space available can be used to expand the PES field.

Abstract: A method for texturing substrate surfaces and a substrate product, such as for computer disk drives. Microbump textured substrates are produced having a Rp value of about 20-200 Å and a ratio of Rmax:Rp of about 1.4 or less. In an exemplary embodiment, a microbump textured substrate is produced having colloidal particles on a surface thereof at a density of at least about 25 particles per 25 &mgr;m2, wherein the surface topography includes a Rp value of about 20-200 Å, a micro-roughness Rq of about 10 Å or less, and a ratio of Rmax:Rp of about 1.4 or less. An exemplary method includes first providing a substrate surface having a surface micro-roughness Rq of about 10 Å or less and depositing colloidal particles on the surface to provide a Rp value of about 20-200 Å and a ratio of Rmax:Rp of about 1.4 or less. In a further exemplary embodiment, the method increases the micro-roughness Rq, but to a value that is still less than about 10 Å with Rmax:Rp still of about 1.

Abstract: A method, which may be embodied upon a computer readable medium and executed by a processor, for dynamically adjusting buffer utilization ratios for a hard disk drive system. The method establishes and dynamically adjusts a host transfer goal, which targets the amount of data transferred between host catch-up conditions for a current command. The actual amount of data transferred between host catch-up conditions is compared against the host transfer goal, and the buffer utilization ratios are adjusted when the actual amount of transferred data does not exceed the transfer goal. The host transfer goal is established by a number of operational characteristics, including drive transfer speed, host transfer speed, and track switch locations.

Abstract: A method and apparatus for estimating the flyheight of an airbearing slider in a storage device using variable spindle velocity. The slider floats on an airbearing over a rotating storage disk. The storage disk includes a washboard-sequence having washboard-sections each comprising surface profile variations having a different pitch. The pitches are selected from within a range of values likely to excite an airbearing resonance of the slider as the storage disk rotates at a plurality of discrete velocities. For each of the washboard-sections and at each of the velocities, a maximum amplitude of flyheight modulation of the slider resulting from the slider floating over that washboard-section is measured as the storage disk rotates at that velocity. A determination is made of the velocity/washboard-section combination that caused the largest measured flyheight modulation.

Abstract: A method for graphically representing various types of timing relationships between signals in an electronic system. After a static timing analysis is performed on an electronic system, a set of timing waveforms is displayed. The present invention analyzes the timing relationships between the waveforms, then generates and adds a graphical symbol representing the type and characteristics of the timing relationship to the display.

Abstract: A method and apparatus for improving the reliability of hot spare disk drives in disk arrays and storage networks is provided. The invention analyzes commands issued to active disk drives in a disk array/storage network, and issues commands to the hot spare drives which attempt to emulate the track usage patterns of the active drives. The track usage patterns can be inferred from examining logical block addresses (LBA) of data stored to the active drives, and/or the ratio of read versus write commands issued to the disk drives. By emulating track usage patterns of the active drives, the spare drives have a roughly equivalent lubricant distribution to that of the active disk drives. This provides increased reliability when the hot spare drives are called into active service.

Abstract: A method to improve object-oriented computer processing by reducing the incidences of object creation and garbage collection. A compiler, preferably of object-oriented language such as Java, identifies a list of objects that are fixed in value or are constant and places those fixed/constant objects in a separate class, a root class, which is loaded at run-time along with all the other classes. Upon creation of an object table, a separate object table may be created for those objects in the root class thereby immunizing the fixed entries from garbage collection and the values will not be erased from memory. Alternatively, the fixed/constant objects can be placed in an object table along with other variable objects but can be marked as active by changing the bit values in a field of the object table.

Abstract: A position error signal indicative of the distance between an expected position of a magnetic head relative to the track centerline of a magnetic data storage and retrieval system and an actual position of the magnetic head relative to the track centerline is detected. An absolute value of the position error signal is determined and stored. The detection, determination, and storage is repeated over several revolutions of the magnetic data storage and retrieval system. A maximum of the absolute values of the position error signals is then determined and compared to a threshold value. If the maximum of the absolute values of the position error signals exceeds the threshold value, a warning signal is propagated. An alternative embodiment similarly predicts the possibility of head-disk crash on the basis of the maximum value of several samples of the squares of the position error signals.

Abstract: Method, program product, and system for the probabilistic determination of storage device enclosure-to-storage device relationships in a storage system, when the exact relationship is unknown. A table is built at storage system startup representing the initial storage device enclosure to storage device relationship. For efficiency, as topology changes occur within the storage system, the table is not updated to reflect the topology change. When a user wishes to access a specific storage device enclosure, the table is opened, and the most recently added storage device entry for the selected enclosure is chosen. The chosen storage device is queried for its current physical location. If the storage device still resides within the selected enclosure, the user access the enclosure via the chosen storage device.

Abstract: Embodiments of systems, methods and article of manufacture provide for readback signal detection and analysis. One embodiment provides an in-situ system to detect envelope traces of a readback signal. Using the envelope data, the presence of undesirable activity and/or storage medium surface conditions may be determined. For example, head modulation may be determined. Upon detection of a modulation event in a sector or a track, the compromised data may be recovered using a signal processing system. Another embodiment provides for detection of a thermal signal component in a readback signal. The thermal signal is processed for surface information indicative of the surface condition. Information indicating a defect may then be used to avoid storage areas having the defects.

Abstract: A hard disk drive actuator includes a plurality of arms for holding the heads over the disks. Each arm has one or more contaminant collectors for collecting contaminants, such as airborne particles, humidity, and/or organic gasses during operation. The contaminant collectors can take a variety of forms, including air porous filters mounted within existing cutouts within the plurality of arms. In this instance, the plurality of arms may be aerodynamically shaped to create a pressure differential between the top and bottom surfaces of the arms, causing an increased airflow through the filters. In another instance, the contaminant collector is a material applied to the top and bottom surfaces of the plurality of arms which attracts and/or captures airborne particles during normal operation.