Flash Illuminates Mobile Digital StorageDocument Transcript
A Storage Vision #2
Flash Illuminates Mobile Digital Storage
Thomas M. Coughlin
A brief history of flash memory
In the early 1980’s semiconductor engineers developed concepts for non-volatile data storage
devices. This technology allowed storage of trapped electrons in “cells” to create an array of
addressable storage nodes. The trapped electrons were prevented form leaking out of the cell by
a large energy barrier creating a non-volatile storage architecture. The data in these cells could
be written and then they would retain the data until the cell was erased or “flashed” . The cells
could be organized to provide different logical functions such as NOR or NAND. NOR-based
flash memory has faster read speed, but longer erase and write times and is most suitable for
infrequently updated code such as BIOS or firmware. NOR is still used in applications such as
cell phones and set top boxes but increasingly NAND-based flash memory is finding its way into
more and more applications requiring data storage.
The initial work on flash memory was published by Dr. Fujio Masuoka of Toshiba in 1984 and
significant development began at many companies in the later 1980’s. SanDisk, funded in part by
Seagate Technology was established in 1988 to develop NAND-based flash memory technology
and owns a significant amount of flash memory IP. Today the largest manufacturer of flash
memory is Samsung Electronics. Samsung entered the flash market in 2001 and currently has
about 50% market share of NAND flash. Samsung flash memory comes in all form factors and in
many mobile applications.
The role of flash in mobile CE and other applications
Flash memory represents a vision for rugged non-volatile digital storage devices and enabled the
development of new mobile electronic markets. Flash provided a useable storage capacity,
shock resistance and low power storage for electronics designers. Devices such as low cost
MP3 players and digital still cameras were enabled by the availability of embedded and
removable flash memory storage in the 1990’s. Figure 1 shows a 64 GB compact flash storage
device from Samsung.
Figure 1. Samsung 64 GB Compact Flash Storage Device
Since 2001 NAND flash storage capacity for a given number of flash chips has doubled annually.
In 2006 8 Gb components are shipping and by 2008 32 Gb components should be shipping.
Using reduced lithographic line widths and multiple bits per cell to boost storage capacity flash
memory is giving competing storage technologies a run for their money. As the storage capacity
of flash memory increased mobile flash memory began to show up in more and more mobile
devices from PDAs to video cameras.
In 2000 storage companies began to provide USB based memory devices (USB drives) that
could be easily carried from computer to computer, see Figure 2. These mostly flash-based USB
devices displaced floppy disks for computer “sneaker net” data transfers within a few years.
Technologies such as Migo and U3 are offering ways to even run applications from USB-based
devices allowing the possibility of carrying data and applications on a small mobile device for use
in computers at a destination that may not have the applications resident. Perhaps in the future
some people will use USB drives for their current working files using computers at their
destination as if they were their office computers.
Figure 2. USB Flash Memory Device
With the introduction of Vista, notebook computers may use hard disk drives with 256 MB or more
of NAND flash as a write cache and also to hold some operating system boot-up data to allow
more rapid boot up when the computer is starting. These products are being called
ReadyDrive . In addition to faster computer boot-up the NAND cache stores data to be written
on the disk drive so the disk drive does not have to write data to the disk as often. This can
reduce the power consumption of the disk drive significantly, perhaps as much as 90%. Overall
laptop power consumption would only be reduced by about 8-12% since the storage component
only consumes around 10-15% of the total laptop power (the display is the biggest power
Samsung has also introduced solid state drives for use in ultralight laptop computers with current
capacities as high as 32 GB, Figure 3. These devices are the in the form factor of 1.8 or 2.5-inch
hard disk drives (called solid state drives or SSDs). Although the price is much higher than for a
higher capacity hard disk drive-based ultralight laptop the company expects the faster data
access, greater ruggedness, longer battery life and lighter weight to appeal to some market
segments. As the storage capacity of NAND flash chips increases in coming years such SSDs
could provide adequate storage for lighter weight usage travelers or those with ready access to
on-line storage. There is already a market for such products for heavy industrial or military
Figure 3. Solid State Drive with 16 GB
Flash projections and its role in bettering our lives
According to Semico total annual capacity shipments of flash memory could exceed 24 EB
(Exabytes or 24 billion gigabytes) by 2010 as shown in Figure 4. The analyst firm also expects
that the price per GB of flash will be less than $2 in the same time frame, Figure 5.
Figure 4. Semico projections for total annual flash memory shipment capacity
Gigabyte Shipments (log)
Billions of GigaBytes Shipped
Figure 5. Semico projections for average price per GB for flash memory
Price per Gigabyte (log)
Average Price per GigaByte
F lash m em ory has unfettered people from fixed consum er electronic and com puter
products. M ore than ever flash m em ory is playing a critical role in the overall product
designer’s storage hierarchy. T his product represents a true vision of the use of digital
storage to enhance the human experience, give us greater freedom of movement and work
and the ability to capture our present situation where ever we may happen to be.
The annual storage visions conference
Come join us January 6 & 7, 2007 at the Flamingo Hotel in Las Vegas, Nevada for the 6th
annual Storage Visions Conference. Hear our sponsors such as Samsung Semiconductor
explore and describe new opportunities for digital storage and personal and entertainment
content creation, distribution and reception. Meet and network with the creators of the
future and explore all the ways that digital storage will enrich our human experience!