SanDisk has announced Vaulter, an 8GB to 6GB capacity flash memory solid state disk (SSD) from which to boot a PC's operating system. It is in PCI Express mini-card format and works in parallel with a PC's hard drive.

Vaulter is not a pass-through cache for the hard drive (HDD). A PC and notebook OEM will pre-control the placement of the OS and any applications on it. It works in conjunction with a PC's hard drive to store and launch the computer's OS and selected applications. Such systems should start up in a fraction of the time taken by HDD-only systems and should not be restricted to Vista use only.

OS and application performance in general should increase in speed. This is because fewer disk accesses will be needed, for example, when paging occurs between memory and the hard drive nowadays (but in the future the Vaulter SSD). The HDD is relegated to a bulk data storage role.

Tavi Salomon, Vaulter product manager at SanDisk, said: "(Vaulter) consistently boosts user responsiveness by taking advantage of the best native characteristics of a flash-based module and a hard drive. It is the parallel operation of both Vaulter and the hard disk that provides an affordable solution for PC users who will benefit from flash memory performance."

He also said that with Vaulter there is faster response time when a user randomly accesses many small files for repeated operations, such as opening applications, and for unexpected behaviour, such as retrieving new applications or entries on the Internet. Vaulter thus acts as a traditional file access cache as well as an OS boot and application code store.

There are other approaches that add a flash memory unit to PCs.

Intel's Robson technology envisages a flash cache on a PC's motherboard with a capacity range of 64MB to 4GB when it was first demonstrated in 2005. Now it is called Turbo Memory and has 512MB or 1GB modules and is also a PCI Express mini plug-in module, an optional component of Centrino-based notebook systems. It is positioned as a laptop component and not a desktop one.

Robson works with Microsoft Vista’s ReadyDrive technologies and will have no effect with any other OS. It does not store the OS.

Intel also has a Z-U130 SSD for PCs. It has a maximum of 4GB capacity and Intel says it could store an OS.

The Hybrid Storage Alliance of Hitachi, Seagate, Fujitsu, Samsung, and Toshiba, plans flash caches built on HDD controller cards with capacity up to 4GB. They have made no mention of the OS being stored in the flash; it is merely a fast access to data stored on the hard drive.

Vaulter will be on sale to PC and notebook OEMs early in 2008. Customers could see Vaulter-enabled PCs in the second half of next year. Although Salomon said Vaulter would be 'affordable', no price indications have been announced.