Patent Application
20240304212
The present disclosure relates to a magnetic recording method, data storage apparatus, devices, and systems suitable for a data storage device, such as a hard disk drive (HDD), and the method for storing data on a device.
The present disclosure relates to a magnetic recording method, data storage apparatus, devices, and systems for increasing areal density capability (ADC), drive capacity (DC), write data rate (WDR), or the number of random write operations per second (Wops) and improving reliability for a hard disk drive device or system. Certain disclosed examples also illustrate component designs to help integrate a HDD in a cost-effective way.
Magnetic data storage systems are used in a wide variety of devices in both stationary and mobile computing environments. Magnetic data storage systems include hard disk drives (HDD) and solid-state hybrid drives (SSHD) that combine features of a solid-state drive (SSD) and a hard disk drive (HDD). Examples of devices that incorporate magnetic storage systems include desktop computers, portable notebook computers, portable hard disk drives, servers, network-attached storage, cloud storage racks, television set-top boxes, digital cameras, digital video cameras, video game consoles, and portable media players, among others.
These numerous devices utilize magnetic storage systems, particularly HDD, for storing and retrieving digital information. Storage density is a measure of the quantity of digital information that can be stored on a given length of track, area of surface, or in a given volume of a magnetic storage medium. Higher density is generally more desirable since it allows greater volumes of data to be stored in the same physical space. Density generally has a direct effect on performance within a particular medium. Increasing the storage density of disks requires technological advances and changes to various components or storage subsystems of a hard disk. In some approaches, the increase in storage density may result in other data storage system performance penalties, such as sequential write speed and random read/write operations measured by the number of read/write (or input/output) operations per second (Iops).
In order for a hard disk drive to achieve high performance or faster random read and write operations, additional media cache is utilized beyond dynamic random-access memory (DRAM) and other solid-state memory, such as NAND-based flash memory caches, to balance cost and performance. The DRAM and NAND-based cache are typically referred to as the drive buffer. They are temporary data storages embedded in the drive, not on the recording media surface. The additional media caches are typically selected on the media platter surface in specially designated zones. For ultra-high-capacity drives, such as those that use shingled magnetic recording (SMR) write architecture (WA) or heat-assisted magnetic recording (HAMR) technology with interlaced magnetic recording (IMR) write architecture (WA), different write architecture (WA) will slow down the random write operation speed or the number of write operations per second (Wops) compared to conventional magnetic recording (CMR) based on random access. The use of a media cache zone is of particular importance. Since the media cache and data share the same disk surface, the drive capacity is reduced with increasing media cache size. Additionally, many of the new recording technologies (RTs) are based on various energy-assisted magnetic recording technology, which add stress to the write head and reduce its lifetime.
In the past few decades, all hard disk drives (HDDs) have used the same recording technology (RT), recording media, and recording heads for a given drive. As component technology approaches physical limits, new technologies that can be utilized for HDD often provide benefits for areal density capability (ADC), but at the cost of other drive performance penalties. For example, energy-assisted magnetic recording (EAMR) requires increased recording head complexity with additional transducers and sensors, leading to reduced yield and increased component cost. In addition, the recording head lifetime is reduced due to the high energy density through the write pole tip region. Shingled magnetic recording (SMR) requires incoming data to be stored or written in media cache, assembled together, and then rewritten into data bands with a large number of data tracks next to each other. This two-step process significantly slows down the number of write operations per second (Wops) for data center applications when a large number of users have simultaneous write operation requests. It would be ideal to have a hard disk drive solution that can fully utilize both component and system-level technology to ensure high drive capacity (DC) while avoiding performance or lifetime penalties.
The presently disclosed embodiments address many of the issues described above with respect to the existing hard disk drive, particularly for high-capacity drives with a large number of platters per drive. The composite hard disk drive described herein addresses these disadvantages, provides a device solution for a high-capacity drive in a given form factor, utilizes both component and system ADC enablers, significantly reduces the latency penalty and the write operation access time which increases the Wops number as compared to SMR drive. The embodiments disclosed herein are suitable for use in many applications, particular for replacing current high-capacity hard disk drive which have a large number of platters per drive using SMR or potential future recording technology such as heat assisted magnetic recording (HAMR) and bit patterned media recording (BPMR) technologies.
In one of the preferred embodiment, a composite hard disk drive, comprising a number of recording media platters labeled from 1 to n, wherein: n is greater than or equal to 8; there is an integer n1 between 1 and n; typically n1 is 1 or 2; the recording media platter labeled from 1 to n1 are written using a first recording technology (RT) or a first write architecture (WA); all other recording media platters of the number of recording media platters are written using a second RT that is different from the first RT or a second WA that is different from the first WA; the number of flex leads from the preamp flex to each recording head is same within the drive.
The foregoing aspects and many of the attendant advantages described herein will become more fully understood from the detailed description and the accompanying drawings and tables. The drawings constitute a part of this specification and include exemplary embodiments of the disclosure, which may be embodied in various forms. It is to be understood that in some instances, various aspects of the disclosure may be shown exaggerated or enlarged to facilitate an understanding of the disclosure; therefore, the drawings are not necessarily to scale. In addition, the embodiments depicted herein, like reference numerals in the various drawings, refer to the conceptual design of structural elements representing each particular component or element of the apparatus.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
In the following description, numerous specific details are disclosed to provide a thorough understanding of embodiments of the method, system and apparatus. One skilled in the relevant art will recognize, however, that embodiments of the method, system and apparatus described herein may be practiced without one or more of the specific details, or with other electronic devices, methods, components, and materials, and that various changes and modifications can be made while remaining within the scope of the appended claims. In other instances, well-known electronic devices, components, structures, materials, operations, methods, process steps and the like may not be shown or described in detail to avoid obscuring aspects of the embodiments. Embodiments of the apparatus, method and system are described herein with reference to figures.
Reference throughout this specification to “one embodiment,”“an embodiment,” or similar language means that a particular feature, structure, electronic device, method or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment,”“in an embodiment,” and similar language throughout this specification may refer to separate embodiments or may all refer to the same embodiment. Furthermore, the described features, structures, methods, electronic devices, or characteristics may be combined in any suitable manner in one or more embodiments.
Reference throughout this specification, the recording technology (RT) and the write architecture (WA) refers to the component magnetic RT and the WA utilized for the data track of the recording media platters for the hard disk drive. The term: media platter, recording media platter, recording media disk, platter and disk are often refers to the same component of the hard disk drive, i.e., a media platter or media platters in the hard disk drive.
With the numerous devices currently utilizing magnetic storage systems, hard disk drive (HDD) performance demands and design needs have intensified, including a need for increased storage capacity. There is an ongoing effort within the HDD industry to increase memory storage capacity while maintaining the same external drive form factors. Areal density (AD) is a measure of the number of bits that can be stored in a given unit of area, usually expressed in bits per square inch (BPSI). Being a two-dimensional measure, areal density is computed as the product of two one-dimensional density measures on the data track, namely linear density and track density. Linear Density is a measure of how closely bits are situated within a length of track, usually expressed in bits per inch (BPI), kilo-bits per inch (kbpi) or megabits per inch (Mbpi), and measured along the length of the tracks around a disk. Track Density is a measure of how closely the concentric tracks on the disk are situated, or how many tracks are placed in an inch of radius on the disk, usually expressed in tracks per inch (TPI) kilo-track per inch (ktpi) or mega-track per inch (Mtpi). The current demand for larger memory storage capacity in a smaller dimension is therefore linked to the demand for ever increasing storage track density.
Referring to the figures wherein identical reference numerals denote the same elements throughout the various views,
The disk drive 10 also includes an actuator arm assembly 15 that pivots about a pivot bearing 22, which in turn is rotatably supported by the base plate 11 and/or cover. The actuator arm assembly 15 includes one or more individual rigid actuator arms 26 that extend out from near the pivot bearing 22. Multiple actuator arms 26 are typically disposed in vertically spaced relation, with one actuator arm 26 being provided for each major data storage surface of each data storage disk 12 of the disk drive 10. Movement of the actuator arm assembly 15 is provided by an actuator arm drive assembly, such as a voice coil motor 20 or the like. The voice coil motor (VCM) 20 is a magnetic assembly that controls the operation of the actuator arm assembly 15 under the direction of control electronics 17.
The control electronics 17, also referred to as the controller board, manages the operation of the read/write heads, actuator arm, and spindle motor, and handles data input/output to and from the computer. The HDD controller board typically includes Application-Specific Integrated Circuits (ASICs), which are custom-designed electronic components responsible for performing specific functions within the HDD, such as data encoding and decoding, error correction, and data transfer. ASICs are programmed with specific hardware logic to perform these functions efficiently. Another component of the controller board is the Micro Controller Unit (MCU) that controls and coordinates the functions of the hard disk drive. The MCU receives input from various sensors and modules and sends output signals to control the motor and preamp. The controller board also includes RAM (SDRAM) or SSD cache (NAND-based SSD), Firmware Chip, VCM Chip, TVS (Transient Voltage Suppression) Diode(s), Impact/Shock/Vibration Sensor, Temperature Sensor, motor controller, and other sensors and modules. Additionally, the preamp is mounted to the HSA but connected to the controller board via flex.
A suspension 13 is attached to the free end of each actuator arm 26 and cantilevers therefrom. The slider is disposed of at or near the free end of each suspension. What is commonly referred to as the read/write head (e.g., transducer) is mounted as a head unit under the slider and is used in disk drive read/write operations. In practice, additional sensors and transducers are built along with the read/write head to ensure reliable read and write operations. The slider and the transducer are both too small to show in
Perpendicular magnetic recording (PMR) involves recorded bits that are stored in a generally planar recording layer in a generally perpendicular or out-of-plane orientation. A PMR read head and a PMR write head are usually formed as an integrated read/write head on an air-bearing slider. When the disk drive 10 is not in operation, the actuator arm assembly 15 may be pivoted to a parked position utilizing ramp assembly. The head unit is connected to a preamp via head wires routed along the actuator arm 26, which is interconnected with the control electronics 17 of the disk drive 10 by a flex cable that is typically mounted on the actuator arm assembly 15. Signals are exchanged between the head unit and its corresponding data storage disk 12 for disk drive read/write operations.
The typical hard disk drive has one actuator arm assembly 15 that includes all individual rigid actuator arms 26 with recording heads that extend out from near the pivot bearing 22. The actuator arm assembly 15 is controlled by one VCM 20. This type of hard disk drive is called one actuator hard disk drive. Another type of hard disk drive uses two or more actuator arm assembly 15, each actuator arm assembly 15 has multiple actuator arms controlled by its own VCM 20. This type of hard disk drive is called dual actuator drive or multiple actuator drive. For a hard disk drive with multiple actuators, different actuator assemblies are labeled as A1, A2 . . . , where A1 and A2 represent each actuator assemblies respectively in a hard disk drive with dual actuators. Each actuator arm assembly 15 may consist of multiple recording heads, and operated by change of its own VCM 20 coil current. For the case of multiple actuator drives, the actuator arm assemblies 15 are mounted in the same place, with the same pivot point 22. Thus, in top-down view, the first actuator 26 overlaps with all other actuators.
The data storage disks 12 include a plurality of embedded servo sectors each comprising coarse head position information, such as a track address, and fine head position information, such as servo bursts. As the recording head passes over each servo sector, a read/write channel processes the read signal emanating from the head to demodulate the position information. The control circuitry processes the position information to generate a control signal applied to the VCM 20. The VCM 20 rotates the actuator arm 26 in order to position the head over a target track during the seek operation, and maintains the head over the target track during a tracking operation. The head unit may utilize various types of read sensor technologies such as giant magnetoresistive (GMR), tunneling magnetoresistive (TMR), other magnetoresistive technologies, or other suitable technologies.
There is an ongoing effort within the magnetic recording industry to increase memory storage capacity. Typically, different types of HDD are labeled by the write technology (also referred to as: the recording technology or RT) utilized in drive operation, with the current technology called perpendicular magnetic recording (PMR), and corresponding HDD called PMR drive.
There are a number of recording technologies (RTs) that can be utilized for a hard disk drive. Beyond current products use perpendicular magnetic recording (PMR), there are still other recording technologies (RTs), such as: heat assisted magnetic recording (HAMR), the microwave assisted magnetic recording (MAMR), other energy assisted magnetic recording (EAMR), bit patterned media recording (BPMR) and heated dot magnetic recording (HDMR).
PMR drive involves recorded bits that are stored in a generally planar recording layer in a generally perpendicular or out-of-plane orientation. In a PMR drive, the recording technology (RT) is based on PMR. The corresponding components such as recording media and recording head are all optimized for PMR technology. In PMR drive, higher ADC requires smaller bits, which cause thermal instabilities. To avoid this, media with high magneto-crystalline anisotropy (Ku) may be used. However, increasing Ku also increases the coercivity of the media, which can exceed the write field capability of the write head.
Since it is known that the coercivity of the magnetic material of the recording layer is temperature dependent, one method to address thermal stability and increased coercivity is to use heat-assisted magnetic recording (HAMR or in some place, also called: thermally assisted magnetic recording or TAMR), wherein high-Ku magnetic recording material is heated locally during write operation by the write head to lower the coercivity enough for writing to occur, then let the coercivity/anisotropy to be high enough for thermal stability of the recorded bits at the ambient temperature of the disk drive (e.g., the normal operating or “room” temperature of approximately 20-30° C.). In some HAMR systems, the magnetic recording material is heated to near or above its Curie temperature. The recorded data is then read back at the ambient temperature by a conventional magnetoresistive read head, e.g., a giant magnetoresistance (GMR) or tunneling magnetoresistance (TMR) based read head. One type of HAMR disk drive uses a laser source and an optical waveguide coupled to a transducer, e.g., a near-field transducer (NFT), for heating the recording material on the disk. A near-field transducer is an optical device with subwavelength features used to concentrate the light delivered by the waveguide into a spot smaller than the diffraction limit and at distance smaller than the wavelength of light. In a HAMR head, the NFT is typically located at the air-bearing surface (ABS) of the slider that also supports the read/write head, and rides or “flies” above the disk surface while creating an optical spot on the disk. In a HAMR drive, the recording technology is based on HAMR. The corresponding components such as recording media and recording head are all optimized for HAMR technology. Note that due to additional optical energy being utilized to heat up the recording media by a few hundreds of degrees, the total energy density at the writing location is high as compared to PMR, therefore, typically HAMR head lifetime is low as compared to PMR. For a large capacity drive with large workload, significant effort to improve write head reliability and lifetime is still needed to achieve a reliable HAMR drive.
Another energy assisted magnetic recording technology is called microwave assisted magnetic recording (MAMR). In MAMR, a high radio frequency (rf) magnetic field is delivered to the recording layer during write process, typically by adding spin-torque oscillator (STO), which generates rf field at several to tens of gigahertz, which help recording media reduce its switching field. This additional structure will be integrated with a perpendicular magnetic recording (PMR) head, therefore, MAMR write head is also different from standard PMR head, which includes an STO structure as well as an electric current path that drives the STO to produce an rf magnetic field. Since in MAMR, the media switching field is reduced, therefore, the recording head can be utilized to write higher anisotropy media and with a smaller grain size. The MAMR media will have higher anisotropy, smaller grain size and different microstructure as compared to PMR media. In a MAMR drive, the recording technology is based on MAMR. The corresponding components such as recording media and recording head are optimized for MAMR technology.
There are other energy assisted magnetic recording technologies, such as energy/electric current assisted magnetic recording (EAMR) where an additional electric current flows through the write pole tip. This electric current is called assisted current if it is passing through the writer's shield. The electric current will enable writer pole tip complete the magnetization switching and reach saturation magnetization state faster than conventional PMR head in the write operation. The added field also helps recording media switching. In EAMR drive, the recording technology is based on EAMR. The corresponding components such as recording media and recording head are all optimized for EAMR technology.
In another approach, a current can be applied through the write pole tip into the recording media. This is typically called the shunt current, and the recording technology is often referred to as current assisted magnetic recording (CAMR). The shunting current will help to reduce the media switching field due to self-heating. In CAMR drive, the recording technology is based on CAMR. The corresponding components such as recording media and recording head are all optimized for CAMR technology.
There are other magnetic recording technologies, such as bit patterned media recording (BPMR) or heated dot magnetic recording (HDMR), where the recording media is based on well aligned discrete dot patterns and the recording head will be optimized for that particular media. In the case of HDMR, additional thermal energy is applied to the media dot during the write process. In any of the energy assisted magnetic recording technologies mentioned above, the recording head and recording media needs to be designed and optimized particular for that technology, and typically their design, structure, materials, processes to be different from PMR head and media. Each of the energy assisted technologies require large changes of recording head and media component change, and they are often referred to as component technology for ADC enablers.
In addition to component technology to enable DC, there are different write architecture (WA) technologies that can be utilized for HDD. Throughout this disclosure, the write architecture (WA) can be defined as: conventional magnetic recording (CMR); shingled magnetic recording (SMR); interlaced magnetic recording (IMR); blocked magnetic recording (BMR). The write architecture (WA) in traditional HDDs, called conventional magnetic recording (CMR), has each data track being accessed, both in read and write operations, in a random fashion. This allows drive operation at a fast speed. There are alternative write architectures (WAs) that have been proposed or implemented for different data storage products.
One of the WAs is called shingled magnetic recording (SMR), where the data track is grouped into data bands. Each band consists of a large number (typically larger than 10) of data tracks. Within each band, the written in data in the consecutive tracks partially overwrite or trim the previous written track. By optimizing recording head design and media properties, higher storage capacity can be achieved using SMR. In SMR, the trim of tracks within a band or between different bands next to each other is always from one side.
Another WA is called interlaced magnetic recording (IMR). In IMR, the recording data track is labeled as top/bottom tracks (or even/odd tracks). The bottom (odd) tracks are written before the top (even) track write. Therefore, the bottom (odd) track can be written with a wide track pitch, which enables high kbpi. The top (even) track has limited ATI, as it will not experience a written pattern in any of the neighboring tracks. Therefore, the top (even) track can be optimized for ktpi. The IMR with HAMR can further improve the ADC of the HAMR HDD.
A more generalized WA is called blocked magnetic recording (BMR). In BMR, the neighboring data tracks can be differentiated as top, middle and bottom tracks, and several tracks can be grouped into bands. Different from SMR, the trim of tracks between neighboring tracks can be from opposite directions. The number of middle tracks within one band can be multiple tracks. In case the number of middle tracks is dropped to zero, the BMR is returned to the configuration of IMR. In case the number of middle tracks within one band is zero on one side, while the opposite side is not respective to the top track, the BMR is returned to the configuration of SMR. In other words, the IMR and SMR are both special configurations of BMR.
For WA other than CMR, the data track is not being written in a completely random fashion. Therefore, when a large number of incoming write requests are received simultaneously, the drive has to organize the data in such a way to write data tracks following the architecture set by the firmware. It is not only adding the complexity of the write operations, but also slowing down the write operations. There are many different ways to improve efficiency, as compared to CMR, SMR, IMR or BMR all has performance penalty which is typically reflected by reduced the number random write operations per second (Wops) capability a hard disk drive can achieve. To mitigate this effect, one of the approaches is to create CMR based media buffer zones/tracks on small regions of the disk surface for each recording media disk platter surface, and write the data temporarily before it can be organized, packed or optimized, then put the organized data to dedicated bands or tracks. These media buffer zones are typically called media cache. As compared to other approaches using DRAM and NAND flash storage for drive cache, this approach is more cost effective. The additional media cache will take part of the recording space on the media platter otherwise can be utilized for store data. Therefore, an increase in media cache size as a percentage of recording media platter area improves the write performance, but the total DC will be reduced. For SMR drive, the media cache is written in CMR mode, different from the data track using the same recording head. The same recording head on that media surface has to be operated in dual modes. The same recording media has to be optimized for both CMR and SMR. This often leads to an ADC penalty in the media cache zone. Therefore, a larger area is desired for the media cache zone in order to mitigate the performance penalty. No matter what RT or WA is utilized in a HDD.
In all existing large capacity HDDs, there are a number of platters in each HDD assembly, only one RT and one WA is utilized within the drive for its data tracks. In one embodiment, a composite hard disk drive comprises a number of platters labeled from 1 to n, where n is equals to or larger than 2; wherein there exist two number n1 and n2, where n1 and n2 are integers between 1 and n; n1 is not equals to n2; wherein the data tracks for the media platters n1 and n2 are written using one of the following: 1) different RT; 2) different WA; or 3) different RT and different WA.
In another embodiment, the data property can include other aspects of data files, the origin of data, the history of data creating and modification etc., use of smart algorithms can also help to determine and decide if particular data files need to be rewrite frequently. The composite HDD can assign small data files and data files that are likely to be rewrite frequently to be written to disk n1, and keep them on disk platter n1, wherein disk platter n1 can be based on PMR. While assigning other files or organizing other files and rewriting them to other disk platters. This approach is of particular importance, since for the assisted technologies, the recording head lifetime is limited. Using the optimized write method for composite HDD allows PMR head and media to handle most write operations, and reduce other platters write frequency and power one time. Thus can help to prolong the whole HDD lifetime.
Any of the above mentioned composite hard disk drive embodiments provide significant benefit as compared to conventional hard disk drives. In addition to ensure high DC with high Wops, the composite hard disk drive also allow additional optimization and redistribution of the write load, which will further improve the drive lifetime. In most energy assisted recording technology such as HAMR, MAMR, EAMR etc., the recording head lifetime is limited due to high energy density near the write pole tip during the write operations, use of composite hard disk drive can significantly reduce the required continuous write operation time for the write head corresponding to the less reliable part of the drive. This composite hard disk drive will become a big enabler to allow HAMR and other energy assisted magnetic recording technology to be implemented into hard disk drive products.
In various embodiments, the composite hard disk drive can use a first and a second RT. One of the preferred embodiments is to have one disk use the first RT, and all other disks use the other RT. In a preferred embodiment, the first RT is based on PMR. In other embodiments, the hard disk drive can use a first and a second WA. One of the preferred embodiments is to have one disk use the first WA, and all other disks use the other WA. In a preferred embodiment, the first WA is based on CMR.
The following list of aspects reflects a variety of the embodiments explicitly contemplated by the present application. Those of ordinary skill in the art will readily appreciate that the aspects below are neither limiting of the embodiments disclosed herein, nor exhaustive of all of the embodiments conceivable from the disclosure above, but are instead meant to be exemplary in nature.
In practice, the composite HDD uses a recording media and recording head that matches with the recording media for each media platter surface. Since each media platter is corresponding with a given RT with the matching recording head. Each recording subsystem including the recording head and media are optimized to match with each other. There is little interaction between disks during read and write operations, as compared to conventional SMR approach when different WA between data tracks and media cache zones. Different recording media platters can still be mounted on the same disk spindle with minimal change to the drive architecture. Different recording heads can be mounted on its own slider, and connected with the same actuator arm with all recording head assembly to be of the same form factor. Therefore, the integration of this type of HDD will induce minimal change. Since PMR recording technology with CMR WA has been developed with reliable recording head and media. All other media platters and the recording heads will have less write-power-on hour during 5 years' service life time. Therefore, this will help to effectively reduce the required head lifetime for all other recording heads in the same drive. In the composite HDD, both capacities, write operation performance and the drive lifetime can be improved simultaneously.
The embodiments were chosen and described to best explain the principles of the invention and its practical application to persons who are skilled in the art. As various modifications could be made to the exemplary embodiments, as described above with reference to the corresponding illustrations, without departing from the scope of the invention, it is intended that all matter contained in the foregoing description and shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents. Modifications and variations may be made to the disclosed embodiments while remaining within the spirit and scope of the method, system and apparatus. The implementations described above and other implementations are within the scope of the following claims.
The present application partially claims the benefit of priority to U.S. patent application Ser. No. 17/559,214, entitled “Composite Hard Disk Drive,” filed on Dec. 22, 2021.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17559214 | Dec 2021 | US |
| Child | 18118094 | US |
