Not a caching or hybrid drive, but a separate SSD and HDD
Today WD is unveiling a slick 2.5" hard drive it calls the Black Squared Dual Drive. Unlike previous 2.5" drives which featured either a spinning hard drive or an SSD, or the two combined in a caching setup, this model features two separate volumes that coexist peacefully in one chassis. It's designed to be a high-performance drive for those with single-bay devices, such as a notebook, SFF rig, or AIO. If you fall into this category, and can squeeze your OS onto a 120GB volume, Christmas has indeed come early.
A few months after it started shipping the Scorpio Blue 7mm hard drive, aimed at Intel-based ultrabooks and other ultra-thin and light notebooks, Western Digital on Monday up the ante by announcing what it claims is the “world's thinnest 2.5-inch hybrid hard drive.” The world’s largest HDD maker said it has begun sampling the 5mm-thin hybrid HDD and will be showcasing the technology during the upcoming WD Investor Day on September 13, 2012.
In the storage world, nothing matches a solid-state drive for speed, and nothing matches a mechanical hard drive for capacity and price per gigabyte. Recognizing these two great tastes would go great together, many vendors have attempted to find the perfect hybrid storage solution, with variable—and often clunky—results. Seagate’s Momentus XT, which we first reviewed in September 2010, offered a 500GB 2.5-inch drive with 4GB of NAND flash with an adaptive algorithm to ensure that the most frequently used files are mirrored in the NAND. This means your boot drive feels faster than a mechanical drive, if only for the stuff you use the most. We liked the first Momentus, but complained that it could use more NAND. Seagate aims to remedy that complaint with this new Momentus.