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Micron Blog

Part 7: NAND in SSDs

The Marriage of NAND Flash and SSDs

  1. Tape Drives
  2. Magnetic Drum Memory
  3. The Birth of the Hard Drive
  4. The 5.25-inch Hard Drive
  5. Limitations of the HDD
  6. The RAM SSD & NAND
  7. NAND in SSDs

NAND technology paved the way for a new breed of SSD that is able to emulate HDDs in most enterprise or consumer applications. These SSDs are far less expensive than DRAM-based SSDs and still offer several advantages over HDDs—particularly in terms of performance and reliability.

Because NAND-based SSDs are a solid state technology, they have no moving parts and offer much better performance than HDDs. When a command is issued to an HDD, the drive must seek with its actuator, spin its platter, and then transfer the data back to the host. But SSDs have no moving parts (requiring only the time it takes to process the command), and they have random access times as quick as 20µs [52].

Figure 11: HDD External Storage I/O Timing

The improved performance of new SSDs equates to 10,000 IOPS compared to less than 450 IOPS for the fastest HDDs [53].  When used in enterprise applications like Internet banking, SSDs might significantly boost information access.

Figure 12: SSD External Storage I/O Timing

With no moving parts to wear out or break, an SSD will outlast almost any HDD, which typically has only a three- to five-year life expectancy if it is not bumped, banged, or dropped. By comparison, a modern SSD might last twice that long and do so without the sensitivities to mechanical shock and while consuming only a fraction of the power.

RAIDs, Connections, and the Next Step for SSDs

SSDs can go anywhere an HDD can, so for enterprise and consumer applications alike, SSDs are replacing HDDs—a trend that is sure to continue for the next decade or more. But using an SSD as a drop-in replacement for an HDD is not necessarily using SSDs to their fullest potential. RAID controllers, HDD interfaces, and storage subsystems have been optimized for the characteristics of rotating magnetic media and may be a bottleneck for solid state storage. Due to the flexibility of NAND solid state storage, SSDs will once again change the picture of storage in computers. NAND-based storage will become more integrated into the computer and will enable new generations of applications. Productivity gains will be measurable and the power savings, dramatic.


Digital storage has come a long way since 1956, with the most recent innovation being SSDs.  And now that SSDs are gaining new ground with the advancements made possible by NAND Flash technology, they represent the next evolutionary step for storage applications.

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Notes: [52] Wong, page 15. [53] Justin Sykes, "SSDs to Boost Data Center Performance," Micron Technology, Inc. Boise, Idaho, (July 30, 2008): page 3.

About Our Blogger

Dean Klein

Dean Klein is Vice President of Memory System Development at Micron Technology. Mr. Klein joined Micron in January 1999, after having held several leadership positions at Micron Electronics, Inc., including Executive Vice President of Product Development and Chief Technical Officer. He also co-founded and served as President of PC Tech, Inc., previously a wholly-owned subsidiary of Micron Electronics, Inc., from its inception in 1984. Mr. Klein’s current responsibilities as Vice President of Memory System Development focus on developing memory technologies and capabilities.

Mr. Klein earned a Bachelor of Science degree in electrical engineering and a Master of Electrical Engineering from the University of Minnesota, and he holds over 220 patents in the areas of computer architecture and electrical engineering. He has a passion for math and science education and is a mentor to the FIRST Robotics team (www.FIRSTInspires.org) in the Meridian, Idaho school district.

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