The notion of replacing PCs' hard-disk drives (HDDs) with solid-state NAND flash memory long has been pondered, but never given much serious consideration. Yet the success of Apple's flash-based iPod nano is spurring speculation that NAND could become a legitimate competitor for HDDs in PCs.
Compared to HDDs, flash offers improved reliability, lower power consumption, silent operation, and faster access time. NAND also is more reliable than HDDs since it doesn't require mechanical components like the spindle and actuator motors, the read and write chassis, and the interface cable connections to operate the hard disk.
These components all are present in HDDs, regardless of the form factor. Furthermore, the HDD's motors and other mechanical parts require much more power than a NAND-based memory. And with NAND flash costs declining dramatically, the memory is becoming more price competitive with HDDs.
In 2003, 1 Gbyte of NAND was nearly 100 times more expensive than an equivalent quantity of HDD storage. By 2009, that price gap will dwindle to a factor of slightly less than 14. And, the price for 32 Gbytes of NAND will be less than $200 by 2008, which will be attractive to most PC OEMs. Yet the HDD is by no means facing extinction. Because NAND remains more expensive than HDDs at high densities, it will mainly serve as a complement, rather than a complete replacement, for hard drives in certain uses.
NAND as an HDD replacement in PCs, the so-called solid-state disk (SSD), will attain only niche acceptance and achieve only 8% penetration of global notebook PC shipments by 2008. By 2010, penetration will reach 22% of global notebook shipments. But for desktops and servers, HDDs will still remain the mainstream storage medium.
In the near term, flash will achieve its greatest success as a complementary storage system, such as in hybrid flash/HDD products and in embedded NAND caching solutions like Intel's Robson. Almost half of the notebook PCs shipped worldwide in 2010 will have embedded NAND caching or hybrid HDDs.