It is an HDD which also has NAND flash memory (NAND) on it. It is also called as "Hybrid Drive" or "Hybrid HDD". This page describes the features (advantages and technologies) of SSHD.
Toshiba's SSHD recorded the score of PCMARK®*1 Vantage several times higher*2 than the conventional HDD (1TB*3). (please refer to the chart below).
PCMark® Vantage Overall Score
Toshiba's SSHD delivers HDD's large capacity - up to 1TB.
Toshiba SSHD is compatible in both physical size and interface with a traditional 2.5-inch HDD. It is recognized by the system as one storage device. The system accesses the drive through single interface without the need for specific device driver software. Comparing to the type of "dual mount", the single interface allows for physical space efficiency within a system.
Toshiba confirmed the feature of MQ01ABD-H / MQ01ABF-H series compatibility*4 with almost 180 PC systems.
Compatibility Test Result (73KB)
Toshiba's SSHD is a lower cost alternative to SSDs while keeping close to SSD performance by the optimized NAND configuration.
The most essential features of the conventional HDD (refer to picture to the left) are "high capacity" and "cost performance". Toshiba's SSHD improved the speed of data read and write, by using NAND as the secondary cache. NAND is the storage device that is used on such as SSDs. The capacity of the data storage per one piece of NAND is very small comparing to one unit in an HDD, however access speed is much faster than an HDD, that reads and writes data on the rotational magnetic media.
Example of Conventional HDD
SSD (refer to the picture to the left) is a storage device that uses NAND as its main memory. Its key feature is high speed of data reading and writing. Due to the higher cost of SSDs in comparison to HDDs, SSDs become more expensive if a user wants high storage capacity. SSHD utilizing NAND on a high capacity HDD improves performance over a conventional high capacity HDD. In other words, Toshiba SSHD delivers higher performance than conventional HDDs with higher capacity and lower cost than SSDs.
Example of Client SSD
We are referring to "Dual" mount here as kind of PC where its storage is both high capacity and high speed at the same time, like some Ultrabook™*5 systems. A "Dual" mount type PC has two storage devices in it; HDD and cache SSD (smaller physical size and data capacity than the normal SSD). While it achieves the high capacity and high speed at the same time, it has the disadvantage in the difficulty to control the two individual storage devices in the tight space design from the view point of the system design. The SSHD contains HDD and NAND all in one device. Its form factor is compatible with the conventional 2.5-inch HDD and does not require more space within a system. The system recognizes and manages it as a single device without difficult control.
The sentences below describe Toshiba's hybrid technology -- using our combined in-house expertise in NAND, HDD, and SSD technologies.
Toshiba's SSHD dynamically learns the access pattern in each system and directs data to the appropriate tiers, that are DRAM, NAND and disk media. High speed access is achieved by storing frequently-accessed data to NAND.
Toshiba also develops leading-edge microscopic memory technology in NAND. This experience enables Toshiba to boost the NAND technologies, such as defective blocks management, ECC (Error Correction Code), conversion of logical block address, and wear-leveling.