How NAND Flash Has Charted a New Storage Course
NAND Flash at 25: Popularity Doesn't Appear to Be Waning Anytime Soon
NAND flash memory, the nonvolatile solid-state media that has changed the data storage industry in a profound way, is 25 years old this year and has developed into a strategic IT force that no one could have imagined back in its early days.
NAND chips are primarily found in USB keys, solid-state processors, small notebook and tablet PCs, videocams, surveillance cameras, and a number of other connected devicesmostly mobile phones.
Flash memory was invented by Toshiba scientist Dr. Fujio Masuoka around 1980. Toshiba contends that the name "flash" was suggested by Dr. Masuoka's colleague, Mr. Sho-ji Ariizumi, because the erasure process of the memory contents reminded him of the flash of a camera.
Toshiba commercialized NAND flash in 1987; since then, the solid-state storage media has taken off and hasn't looked back. Go here to view a slide show on key milestones in NAND flash history.
Market Has Grown Year-Over-Yearfor Years
The NAND flash market has grown rapidly, with flash memory shipping almost eight times more gigabytes of capacity in 2011 than DRAM (dynamic random access memory, which runs much hotter as a volatile media). NAND flash clearly has become the high-density silicon storage of choice.
NAND flash memory is used in a variety of memory cards and USB drives, and is found in many consumer, industrial and enterprise cloud applications. Apple's iPhone, iPod and iPad are three of the most currently successful commercial usages of NAND flash. Android smartphones and tablets also utilize NAND flash.
The high-density NAND (which stands for "Not AND," a Boolean logic operation that is true if any single input is false) type must also be programmed and read in smaller blocks, or pages, while the NOR type allows a single byte to be written or read independently. NOR flash is preferred for flash devices used to store and run code, usually in small capacities.
Flash Offers New Options to Enterprises
The addition of solid-state NAND flash memory and data storage to conventional magnetic spinning disk hard drives has given enterprises new options to run their key business server and storage applications. Because it has no moving parts, NAND flash is able to process and move data faster from one place to another, thanks to its superior read/write performance. High-transactional applications, such as those used in financial services, retail and Web-based cloud services, often deploy servers loaded with NAND flash.
NAND flash may be looking forward to another 25 years or more in production use. Intriguing solid-state storage media that is in developmentHewlett-Packard's memristor and Intel's phase-change memoryare still years away from commercial use, so NAND flash is expected to be the market leader for a long while.
How NAND Flash Has Charted a New Storage Course
NAND flash also has helped chart a new path in which consumers are able to carry videos, music, books and data with them wherever they go, and not have to leave all that content inside a desktop or laptop PC.
"NAND flash has truly permeated our lives; this technology has been a game changer, making the world a different place and making many of the products we use today possible," said Scott Nelson, vice president of the Memory Business Unit at Toshiba America Electronic Components. "The cost/performance of NAND flash continues to stand the test of time."
For the record, the major difference between NAND and NOR flash, which tend to fit different use cases, is speed. NOR-based flash, which first came to the market from Toshiba in 1988, has long erase and write times but provides full address and data buses, allowing random access to any memory location. NAND flash has much faster read-write performance and thus is in more demand in the markets.
Flash memory stores information in an array of memory cells made from floating-gate transistors. In traditional single-level cell (SLC) devices, each cell stores only one bit of information. Some newer flash memory, known as multi-level cell (MLC) devices, can store more than one bit per cell by choosing between multiple levels of electrical charge to apply to the floating gates of its cells.
Key Facts, Figures on NAND Flash
The evolution of the flash memory types has been remarkable. StorageNewsletter.com, a respected longtime daily email news source for the industry, has been following NAND flash development for years and has a deep archive of vendor information and analysis on the technology. Here are some facts from that archive:
Flash chips: Increased capacity and lower price of flash keys and SSDs depend directly on the manufacturing process of NAND flash memory chips. SanDisk and Toshiba are now offering MLC generation at 128GB capacity in a 3-bit-per-cell chip on a 170mmÂ² silicon die built on the most recent 19nm process. Intel, Samsung, Seagate, Nvidia, LSI, Micron and Western Digital are among the world's major manufacturers of flash processors.
Flash keys (or thumb drives): The first USB flash keys were developed in the late 1990s, the first company in this field being apparently M-Systems, later acquired by SanDisk. In the U.S., IBM sold an 8MB version in 2001, named Memory Key. Now they have reached 128GB and the prices have declined rapidly. The first 128MB devices cost $30 or $234/GB. Now you can get a 64GB unit for $60 or $0.9/GB.
SSDs: Once more, M-Systems appeared to be the first one in SSDs in 1995. Since 1999, SN.com has referenced 590 different models launched by 97 different companies. Among the first ones, BiTMICRO Networks revealed in 1999 the E-Disk SNX35 in 3.5-inch form factor with a capacity from 128MB to 10GB, access time of 500ms, maximum 4MB/s read and write through SCSI-2 interface. The following year M-Systems revealed the FFD SCSI, a 2.5-inch 3GB SSD with maximum 4MB/s read and 3MB/s write. Today one can obtain as much as 16TB into a PCIe SSD (from OCZ) up to 4GB/s read and 3.8GB/s write (Foremay). OCZ recently announced access time as low as 0.04ms for read and 0.02ms for write operations.
Prices have declined drastically in recent years, and SSDs are now competing on a much-improved basis with HDDs. Globally, they still cost about five times more, but all their performance specs are superior. In 2003, Simple Technology's SSD of 2GB was priced at $2,000/GB. Last year, a 650GB unit from OCZ was selling at $1.30/GB.
Toshiba's commemoration of the 25th anniversary of the invention of NAND flash will continue throughout 2012. Included in the celebration will be industry events and consumer participation. An interactive campaign that will reference industry voices and experiences exploring the impact of NAND flash is forthcoming.
Chris Preimesberger is eWEEK Editor for Features and Analysis. Twitter: @editingwhiz.