Vol. 76, No. 6, November 2021

Special Reports

Hard Disk Drives toward Realization of Data Society



The volume of data generated and collected in various situations worldwide has been exponentially rising in recent years with the advent of a full-fledged data society, increasing the value of accumulated data to unprecedentedly high levels. With this as a background, hard disk drives (HDDs) hold promise as a means of economically and efficiently storing and utilizing these large volumes of data due to their advantage in terms of total cost of ownership (TCO), and further broadening of their applicability in the data center and surveillance camera markets can be expected.

The Toshiba Group has been actively focusing on the development and expansion of large-capacity HDD products through the application of innovative technologies such as assisted recording technologies, with the aim of significantly contributing to the progress of the data society.

TAKEO Akihiko / SUGIYAMA Hiroshi

The widespread utilization of data in society as a whole due to the dissemination of cloud services and the progress of data analysis technologies using artificial intelligence (AI) has given rise to the need for large-capacity hard disk drives (HDDs) for nearline storage applications including data centers.

Under these circumstances, Toshiba Electronic Devices & Storage Corporation has been promoting the practical implementation of energy-assisted magnetic recording technologies to realize HDDs with higher areal recording density. We have developed and released the MG09 series of 3.5-inch nearline HDDs with a storage capacity of 18 Tbytes as the first products incorporating our proprietary flux control microwave-assisted magnetic recording (FC-MAMR) head.


With the rapid expansion of data center businesses offering platforms to create various Internet services, demand has recently been growing for larger capacity hard disk drives (HDDs) so as to store huge volumes of electronic information.

Toshiba Electronic Devices & Storage Corporation has been taking the initiative in developing shingled magnetic recording (SMR) technologies, which are a strong driver of the trend toward further increasing the storage capacity of HDDs. Taking advantage of the features of SMR, these technologies include a servo technology capable of improving the prediction accuracy of head positions and a redundant sector processing technology capable of improving the quality of recorded data. We have now developed the MA09 series of 3.5-inch HDDs for data centers with the industry’s largest capacity of 20 Tbytes through the application of these technologies to the MG09 series HDDs.

KURAKANE Hiroshi / AOKI Takao

Accompanying the ongoing expansion of the surveillance camera market, strong demand has arisen in recent years for large-capacity, high-performance hard disk drives (HDDs) for surveillance camera systems including surveillance digital video recorders and surveillance network video recorders.

In response to this market demand, Toshiba Electronic Devices & Storage Corporation has released the DT02-VH series of 3.5-inch shingled magnetic recording (SMR) HDDs for surveillance camera systems. The DT02-VH series offers the following features: (1) a large storage capacity of 2 Tbytes/platter and (2) high-performance capability that makes it possible to connect up to 64 cameras through direct recording of video data simultaneously sent from multiple cameras to the SMR area on the disk without using a media cache, in addition to a conventional magnetic recording (CMR) area provided on the disk to directly record system data having a small data size.

MAEDA Tomoyuki / YAMADA Kenichiro

Hard disk drives (HDDs) providing access to large volumes of data with a reasonable latency time at low cost are playing a key role in information storage devices accompanying the expansion of high-level machine learning and artificial intelligence (AI). Efforts are being made to realize HDDs with higher recording density.

The Toshiba Group has positioned microwave-assisted switching microwave-assisted magnetic recording (MAS-MAMR) technology as a next-generation energy-assisted magnetic recording technology to increase the recording density of HDDs, and has been engaged in the development of MAS-MAMR aiming at its practical realization. As part of this approach, we have designed a new type of spin torque oscillator (STO) and confirmed through simulations that it can achieve an improvement in oscillation efficiency as well as a reduction in the expansion of the microwave magnetic field in the cross-track direction. This type of STO is expected to increase recording density, leading to a breakthrough in achieving the practical use of MAS-MAMR.

TOKUDA Kota / KAJI Keiko / ISHIZAKI Kiyokazu

As a consequence of the increase in data storage capacity of hard disk drives (HDDs), there is a growing need for high-density mounting technologies for the printed circuit boards installed in them. In particular, flexible printed circuit boards (FPCs) incorporated in HDDs are facing critical issues including not only severe external restrictions but also the difficulty of mounting preamplifier integrated circuits (ICs) due to the increase in the number of pins and the size of packages. From the standpoints of both quality and productivity in HDD manufacturing, it is therefore necessary to optimize the specifications of FPCs from the conceptual design phase.

Toshiba Electronic Devices & Storage Corporation has been taking the initiative in developing high-density printed circuit board mounting technologies to increase the capacity of 3.5-inch HDDs. We are promoting determination of the specifications of key parts at the initial stage of the design phase and optimization of design in consideration of manufacturing quality, mounting processes, and reliability, as well as reliability verification tests. These efforts are making a major contribution to the realization of high-density, high-reliability printed circuit boards suitable for 3.5-inch HDDs.

Feature Articles

SHIGETA Tomoaki / TAKANO Toshiya

Reinforcement learning (RL) is a machine learning method that makes it possible to automatically acquire an enhanced control strategy by changing the behavior of the controlled object through trial and error. As it is important for motors in the industrial field to meet requirements for torque and speed accuracy, the application of RL is considered to be an effective means of shortening the time required to change control models that depend on individual driving conditions.

Toshiba Infrastructure Systems & Solutions Corporation has developed a method to automatically generate a speed control model using RL in real time, using permanent magnet synchronous motors (PMSMs) as a case study. From the results of experiments using an actual PMSM together with a motor that can simulate the load conditions of a compressor, we have confirmed that this RL-based speed controller makes it possible to suppress speed ripples by 1.6% compared with the conventional method using proportional-integral (PI) control.

SUMI Takeshi / ONODERA Akito

To assure the quality of software during its development, it is necessary to conduct tests from the upstream stages of the development process by running the software so as to detect any bugs and eliminate their causes. In the social infrastructure field, these tests are often conducted by installing the software in the actual equipment in which it will be used. Considerable time is therefore required to prepare the testing environment, creating a significant issue in terms of delays in the development schedule.

As a solution to this issue, the Toshiba Group has constructed a virtual testing environment that eliminates the need for actual equipment when testing software for social infrastructure systems through the application of virtualization technologies. This virtual testing environment makes it possible to prepare a testing environment more easily compared with the conventional method using actual equipment. It is thus contributing to the shortening of software development periods and the reduction of workloads as it allows testing to be initiated at an early stage.

OHNO Hiroshi / OHNO Akifumi / OKANO Hideaki

In inspection processes at manufacturing sites, demand for the introduction of automated processes using nondestructive, high-speed imaging technologies has been increasing in recent years. However, as it is difficult to obtain clear images of microdefects using conventional optical imaging technologies, the inspection of microdefects still depends on visual inspection performed by skilled workers.

To rectify this situation, the Toshiba Group has developed an optical imaging technology focusing on the phenomenon that the bidirectional reflectance distribution function (BRDF) of light reflected from a surface with microdefects is different from that of light reflected from the normal surface. This novel approach, called one-shot BRDF technology, makes it possible to immediately obtain clear images of microdefects having a depth of as little as a few microns. The microdefects are visualized in colors that differ from those of the surroundings by converting the BRDF differences into color information. Experiments on a prototype one-shot BRDF optical system have verified that this technology has the potential to obtain clear images of microdefects on the surface of various samples, as well as to measure the inclination angle distributions of microconvex shape on the metallic surface with a high degree of accuracy.


Multifunctional peripherals (MFPs) incorporating multiple functions in one unit, such as copier, printer, scanner, and fax, have become widely disseminated in offices. However, the increased speed of processing of these MFPs tends to cause them to emit uncomfortable operation sounds.

In order to provide comfortable work environments, Toshiba Tec Corporation has been developing technologies for MFPs to reduce noise and improve sound quality. We have now developed a method to efficiently make the operation sounds emitted by MFPs more pleasant through the use of the following techniques: (1) quantification of sound quality by means of calculations using an equation representing pleasant sounds and (2) identification of sounds having a major impact on the improvement of sound quality using acoustic simulations. This method is expected to contribute to reductions in the number of prototypes required and development costs by making it possible to predict the effects of such improvements in sound quality prior to prototype manufacturing.

NAKAGOMI Hiroshi / TAKAHASHI Yuya / FURUYA Kenichiro

Geothermal energy has been attracting attention in recent years as one of the renewable energy sources for power generation. However, geothermal power plants are experiencing strong demand for improvement of operational efficiency by suppressing scale adhesion inside their steam turbines, which is caused by mineral particles contained in geothermal steam and results in decreased power output and the deterioration of turbine components.

With the aim of overcoming this issue, Toshiba Energy Systems & Solutions Corporation has developed a scale adhesion suppression method using a surfactant with excellent mineral particle dispersibility as well as a low environmental load. We have conducted experiments using demonstration test equipment installed at an actual geothermal power plant and verified that this method achieves a reduction in the amount of scale adhesion on the metal surfaces. The introduction of this method is expected to improve the operational efficiency of geothermal power plants and contribute to the expansion of geothermal power generation.

OGAWA Akihito / KONDA Kazunobu / HIRAGURI Kazuma

A strong need has arisen in recent years for the further automation of operations in physical distribution warehouses due to the increasing volume of articles being handled and the workforce shortage. However, as various types of articles are stored under different conditions, it is difficult to handle them using conventional automation techniques that are only capable of repeating predetermined operations.

Toshiba Corporation has developed an intelligent picking robot as an edge component of logistics automation solutions that is capable of handling articles with a variety of shapes and different weights. This robot is equipped with a hybrid hand that can be operated in either the suction grip or pinching grip mode according to the targeted object, as well as planning and control techniques for its operation. As a result, the hybrid hand can handle a wider variety of articles having complicated shapes compared with conventional hands operating solely in the suction grip mode. This picking robot is expected to contribute to the advancement of automation in physical distribution warehouses.

Frontiers of Research & Development

Automatic Depalletizing Robot Capable of Handling Randomly Stacked Parcels in Physical Distribution Centers

*Company, product, and service names appearing in each paper include those that are trademarks or registered trademarks of their respective companies.