At present, a few drawbacks yet to be overcome with Solid State Disks include its very high price tag and low capacity compared with traditional hard disks.  So to help offer some of the features of both drive technologies, Seagate has launched its first combination hard disk and flash memory based hard drive, the Seagate Momentus 5400 PSD (Power Saving Drive). 

Its features include 160GB of hard disk capacity and 256MB of flash memory.  With a compatible BIOS (or firmware update) and Windows Vista's ReadyDrive feature, the drive improves the boot time by up to 20% by caching frequently loaded files during boot-up on its flash memory.  It also uses around half the power of a traditional hard drive, giving up to 25% more battery life on a Sony Vaio SZ650 laptop, one of the first to ship with this drive.  Besides boot files, the flash can also used to cache frequently read data and as a disk-write cache to temporarily store data while the main hard disk has spun down.

This hybrid drive retails for $190, which is close to 30% higher than its traditional hard drives.  Over the next 10 years, Seagate plans to offer hybrid drives as an option across its complete portable and desktop line of hard drives.  However, in order for consumers to use these drives, they will need a compatible BIOS or a firmware update to add support for these drives, as BIOS makers and device driver manufacturers have yet to take advantage of flash memory in hard drives. 

Further information can be found in this source InformationWeek article.