Hybrid drives, meaning those that integrate a large chunk of NAND flash memory into a conventional magnetic platter hard drive, have been around for several years now. Their initial splash came with Windows Vista and its ReadyDrive feature, but driver complications bogged down early adoption. It was, relatively speaking, a disaster.
Today, those early impediments are gone. Hybrid drives, such as Seagate’s Momentus XT, are now fully compatible with all PC platforms and every current, major OS thanks to 100% compliance with the AT command set and the intelligence for how data moves between the two media types now being resident in the drive.
Still, the initial bad taste left by hybrids of the last decade has yet to wash away. This is unfortunate, because today’s hybrid technology can deliver a huge amount of benefit to systems for very little cost. In this paper, we’ll explore the details behind modern hybrids, focusing on Seagate’s Momentus XT, and dissect why the technology deserves your attention.
At its simplest, a hybrid drive is a conventional hard drive with a block of nonvolatile (NV) flash memory used for file caching built within the same drive enclosure. Anyone who has used or even read about solid state drives (SSDs) knows that flash memory is considerably faster than hard disk drive (HDD) technology. The seek times involved in spinning platters and positioning read/write heads simply doesn’t exist in the SSD world. While hard drives are inching their way toward 150 MB/s sustained throughput rates, even consumer-class SSDs regularly pull in 200 to 250 MB/s results. On the other hand, SSDs don’t even come close to matching magnetic media’s capacity points or cost per gigabyte.
This is why many users pursue a “hybrid” approach of sorts in their desktop systems, using an SSD as a lower capacity boot drive alongside one or more hard drives for the bulk of file storage and less frequently used applications. This gives maximum performance to OS and primary application files and thus significantly increases overall system responsiveness, especially during boot-up and hibernation operations.
The promise of hybrid drives is having the best of both worlds, the speed of an SSD and the capacity of an HDD, in one drive. If the data being sought for a read is present on the flash memory, the magnetic platters don’t even need to spin up. This not only improves performance but also lowers energy consumption since motor rotation is by far the leading cause of power consumption in storage drives.