Toshiba MG03SCA300 User Manual 2

MK3001GRRB 2.5-inch Hard Disk Drive for Enterprise Use with 300 Gbyte Capacity and 15,000 rpm Rotational Speed

By Toru IWAMOTO / Akihiko MAKITA / Tatsuro SASAMOTO / Keiichi YORIMITSU

Hard disk drives (HDDs) for enterprise use are primary storage devices installed in mission-critical information systems

such as servers and storage systems. In this eld, HDDs must be able to provide high reliability for long-term continuous

workloads (24 hours a day, seven days a week), as well as high performance including a high data transfer rate and high-speed

access. Low power consumption has also become essential in recent years.

In response to the needs of the market, Toshiba has developed the MK3001GRRB 2.5-inch HDD for enterprise use with a

capacity of 300 Gbyte and a rotational speed of 15,000 rpm. The MK3001GRRB achieves a high data transfer rate of 200

Mbit/s, a fast average seek time of 2.7 ms, and low power consumption of 4.0 W in idle state.

1. Introduction

As cloud computing becomes increasingly popular, transaction processing that is faster than ever before is being demanded of servers and storage systems to store and manage various types of information. As the main storage device in mission-critical information processing systems, enterprise-class HDDs are required to have high performance (e.g., high data transfer rates and high-speed access) in addition to high reliability (to realize continuous operation for extended periods of time).

(1) High reliability

High reliability is required to ensure continuous operation (24 hours a day, 7 days a week) for ﬁve years.

(2) High performance

High data transfer rates and high-speed access are essential for processing large amounts of data within a short period of time.

In addition, the recent promotion of energy conservation and green products has led to requirements for low-power consumption storage device.

In response to these requests, Toshiba developed the MK3001GRRB 2.5-inch HDD. This product achieves high performance and high reliability with 15,000 rpm rotational speed, while delivering low power consumption.

2. Drive Overview

Table 1 shows the brief speciﬁcations of the

MK3001GRRB 2.5-inch HDD. The drive has a rotation speed of 15,000 rpm and a storage capacity of 300 GB;

Table 1 Main speciﬁcations of MK3001GRRB 2.5-inch HDD for enterprise use

Item

Interface SAS 2. 0

Interface speed (Gbit/s) (Gbit/s) 6

Storag e capacity (GB) 300 147

Disks (QTY ) 2 1

Heads (QTY )

Power con sumption (W )

Rotat ion speed (rpm) 15,000

Susta ined data tra ns. rate (MB/ s) 147–2 00

Avg. seek ti me (during read ) (ms) 2.7

MTBF (10

MTBF : Mean Time betwe en Failures HDI: H ead Disk Interf ace

Idle mode 4.0 3.8

Low-R PM idle mode 3.0 2.8

h) 1.6

(Embed ded HDI sensor)2(Embed ded HDI sensor)

Specifications

MK3001GRRB MK1401GRRB

enabling up to 200 MB/s sustained data transfer rates. Also, it enables high-speed data access with an average seek time of 2.7 ms. Further, it achieves low power consumption, consuming only 4.0 W while in idle mode. For the interface, we employed SAS 2.0 (Serial Attached SCSI [Small Computer System Interface] 2.0), which is the mainstream HDD interface for enterprise use.

In addition to the MK3001GRRB (storage capacity: 300 GB), we have the MK1401GRRB (storage capacity: 147 GB) and encrypting models such as the MK3001GRRR and the MK1401GRRR in the lineup. The basic speciﬁcations are listed in Table 1.

In the following sections, we describe the hardware and ﬁrmware technologies that we developed to enable both high reliability and high performance.

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3. Hardware Technologies

8 Terminals

Head with HDI Sensor

FPC

FDB Motor

Magnetic Disks

Air stabilizer

Heads

Carriage

Base Plate

Flat coil

Magnet

Figure 1 shows the drive’s internal structure. The mechanical dimensions are compatible with SFF8201/8223, the industry standard for 2.5-inch HDDs. Although drives for mobile PCs are thin as 9.5 mm thick, this drive is 15 mm thick to have a highly rigid base plate and top cover for high-speed rotation. Through computer aided engineering (CAE) using ﬁnite element method (FEM) analysis, we have optimized its mechanical architecture to enable high performance, low acoustic noise, and low power consumption.

We use ﬂuid dynamic bearings (FDB) motor for their low vibration and acoustic noise properties. Bearings are the most critical mechanical component; they decisively inﬂuence HDD operating life and reliability. For this reason, the bearing design we use is the same as ﬁeld-proven conventional bearings. We used glass substrate disks with an outer diameter of 57 mm and a plate thickness of 1.27 mm. An air stabilizer is placed between magnetic disks as indicated by the dotted line in Figure 1. This air stabilizer, which covers 3/4 of the disk periphery, is able to reduce the disk vibration and windage generated by such highspeed disk rotation. Lower vibration and windage is able to reduce positioning errors (disturbance force) during the positioning control of the head over the target track.

Within the disk enclosure of MK3001GRRB (with a storage capacity of 300 GB), four heads are mounted on a carriage. The carriage is in turn mounted on a base via a pair of small-sized ball bearings. The carriage is actuated by a voice coil motor (VCM), which includes a ﬂat coil and magnets.

To achieve a storage capacity of 300 GB, the heads include a newly developed head disk interface (HDI) sensor

Feature Articles

Figure 2 Connection of head-disk interface (HDI) sensor to ﬂexible printed circuit (FPC)—High-density connecting technology was used to implement the HDI sensors,

which are functional elements to increase HDD capacity.

which responds to subtle heat ﬂuctuations between the head and disk, between which there is a very small clearance. In recent years, HDDs have included heaters which are embedded in the heads’ read/write elements. By controlling heater power, the clearances between read/ write elements and magnetic disk surfaces can be ﬁnely controlled, thereby achieving a high recording density. The HDI sensor is a functional element for controlling clearance accurately. When mounting the HDI sensor, as each head has a total of eight terminals—the existing six terminals for read, write, and heater plus two additional terminals—these terminals must be connected to the ﬂexible printed circuit (FPC) with high precision. Figure 2 shows a schematic drawing in which heads with HDI sensors are attached to the FPC, which is in turn mounted on the carriage.

Figure 1 Internal structure of MK3001GRRB—High reliability, high performance, low acoustic noise, and low power consumption were achieved by optimizing the design of the HDD’s mechanical components.

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To enable high speed seeking (average = 2.7 ms), it is important to design a high-performance actuator with both a powerful VCM and a lightweight and vibrationproof carriage. When designing the VCM, we ensured high efﬁciency by optimizing shapes and materials through magnetic ﬁeld analyses. For the carriage design, we conducted a large-scale FEM analysis (Figure 3) for the entire piece of hardware and optimized the shapes and structures of the mechanical components to prevent undesirable vibrations and improve the damping of vibrations, particularly those caused by large VCM forces during the acceleration or deceleration of the carriage.

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