摘要:
Methods, devices and systems include, in some implementations, a method including: writing, using a head having a read element and a write element, a band of spiral sets, the band of spiral sets including a first spiral set and a second spiral set different from the first spiral set; writing, using the write element, servo information that includes one or more sets of servo wedges while the read element is servoing on the first spiral set; and servoing the read element on the second spiral set based on one or more determined conditions under which writing the servo information coincides with reading data from the first spiral set.
摘要:
A solid state drive (SSD) includes an SSD control module configured to determine frequencies corresponding to how often data stored in respective logical addresses associated with the SSD is updated and form groups of the logical addresses according to the frequencies, and a memory control module configured to rewrite the data to physical addresses in blocks of an SSD storage region based on the groups.
摘要:
A system includes a first memory configured to store a first lookup table (LUT) with first metadata. A second memory is configured to store a second LUT with second metadata, wherein the first metadata includes a first mapping between logical addresses and physical addresses. The second metadata includes a second mapping between the logical addresses and the physical addresses. A control module is configured to update the first metadata. The control module is configured to update segments of the second metadata based on the first metadata at respective predetermined times. Each of the segments refers to a predetermined number of entries of the second LUT.
摘要:
Methods, systems, and apparatus, including computer program products are described for calibrating servos, and in some implementations, calibrating spiral servos for use in self-servo-write SSW processes. In one aspect, a method is provide that includes rotating a machine readable medium, and detecting a spiral on the machine readable medium. Detecting a spiral on the machine readable medium includes detecting magnitudes of the spiral and a timing mark, storing a timestamp from a clock signal that corresponds to the timing mark of the spiral, determining a peak of the spiral from the magnitudes, and locking the clock signal to the peak of the spiral using the timestamp.
摘要:
A recording medium can include multiple helicoid patterns arranged in multiple helicoid groups, e.g., first and second helicoid groups. Operating a disk drive can include switching between helicoid groups to maintain the alignment of the head with respect to a target track of the rotating recording medium. Enabling a switch can include receiving a waveform produced by a head operated with respect to a rotating recording medium, generating first information from one or more portions of the waveform corresponding to the helicoid patterns of the first helicoid group; generating second information from one or more portions of the waveform corresponding to the helicoid patterns of the second helicoid group; and analyzing the second information with respect to the first information to generate calibration information. The calibration information can compensate for operational differences between using the helicoid patterns of the first helicoid group and the helicoid patterns of the second helicoid group.
摘要:
Apparatus, methods, and systems can be employed for calibrating servos, and in some implementations, spiral servos are calibrated for use in self-servo-write (SSW) processes. In an aspect, an apparatus includes a timing reference detector configured to determine timing reference information from a back electromotive force signal associated with a rotating machine readable medium, and a servo track window period generator configured to determine a relative location of a spiral on the rotating machine readable medium based on the timing reference information.
摘要:
Methods, systems, and apparatus, including computer program products are described for calibrating servos, and in some implementations, calibrating spiral servos for use in self-servo-write (SSW) processes. In one aspect, a method is provided that includes determining timing reference information on a machine readable medium, locking a clock signal to the timing reference information, detecting a spiral on the machine readable medium, determining a location of the spiral using the clock signal, and calibrating a spiral servo according to the location of the spiral.
摘要:
The present disclosure includes systems and techniques relating to magnetic recording devices, such as disk drives. A recording medium of a magnetic recording device can include multiple helicoid patterns arranged in multiple helicoid groups. A described technique includes receiving a waveform produced by a head operated with respect to the medium; determining, based on the waveform, first phase difference(s) corresponding to a first helicoid group; affecting an alignment of the head with respect to the medium based on the first helicoid group by compensating for the first phase difference(s) to maintain the alignment; determining, while compensating for the first phase differences, second phase difference(s) corresponding to a second helicoid group; and affecting, responsive to a switch from the first helicoid group to the second helicoid group, the alignment of the head with respect to the medium by compensating for the second phase difference(s) to maintain the alignment.
摘要:
Methods, systems, and apparatus, including computer program products are described for calibrating servos, and in some implementations, calibrating spiral servos for use in self-servo-write (SSW) processes. In one aspect, a method is provided that includes determining timing reference information on a machine readable medium, locking a clock signal to the timing reference information, detecting a spiral on the machine readable medium, determining a location of the spiral using the clock signal, and calibrating a spiral servo according to the location of the spiral.
摘要:
A servo control system includes an input that receives spiral signals generated by reading spirals that are prewritten on a magnetic medium. The servo control system further includes a control module that generates spiral correction values for the spirals based on the spiral signals and that determines positions of the spirals based on the spiral correction values.