The past few years have been an exciting time for flash memory. The cost has fallen dramatically as fabrication has become more efficient and the market has grown; the density has improved with the advent of better processes and additional bits per cell; and flash has been adopted in a wide array of applications. The flash ecosystem has expanded and continues to expand— especially for thumb drives, cameras, ruggedized laptops, and phones in the consumer space.

One area where flash has seen only limited success, however, is in the primary-storage market. As the price trend for flash became clear in recent years, the industry anticipated its ubiquity for primary storage, with some so bold as to predict the impending demise of rotating media (undeterred, apparently, by the obduracy of mag-

netic tape). Flash has not lived up to these high expectations, however. The brunt of the effort to bring flash to primary storage has taken the form of SSDs (solid-state disks), flash memory packaged in hard-drive form factors and designed to supplant conventional drives. This technique is alluring because it requires no changes to software or other hardware components, but the cost of flash per gigabyte, while falling quickly, is still far more than hard drives. Only a small number of applications have performance needs that justify the expense.

Although flash’s prospects are tantalizing, the challenge is to find uses for it that strike the right balance between cost and performance. Flash should be viewed not as a replacement for existing storage, but rather as a means to enhance it. Conventional storage systems mix

Today Adam Leventhal,
Sun Microsystems