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Memory On the Move

Varied designs and a lack of standards can faze users of portable memories

13 min read
Memory On the Move

Michael Gansl, one of the United States' top computer consultants, now swaps flash memory cards among his consumer devices the way he once swapped business cards as an IBM salesman. In fact, he expects soon to raise the ante, possibly by this fall. Besides shuttling music, video, and digital image files between his MP3 player, digital camera, personal digital assistant (PDA), and personal computer (PC), he will also be shunting as much as 20 GB of memory from one PC to another.

The development is very recent. Within just the last 24 months, myriad audio, video, PDA, and cellular products have equipped people not only to tote around data, images, and audio, but in addition to swap the devices between various types of hardware.

Competing for this US $11 billion market are several venerable but revitalized memory systems as well as new storage technologies: flash memory cards, PC memory cards, and small disk drives. Flashers, a relatively young technology, contain one or more nonvolatile solid-state memory chips. They have no moving parts and retain data in the absence of power. Like these, but an industry unto itself, is the PC Card; now almost 10 years old, the business-card-sized memory and application device is heavily used to add functions to mobile computers. The spinners are a completely upgraded group of rotating-disk drive systems based on both magnetic and optical technologies.

A flash flood

Jockeying for Market Share

Jockeying for Market Share 
Without a single standard format in place, memory cards and their makers are fighting for market share [top]. Meanwhile, the number of products using flash memory cards is growing rapidly [bottom]. Click on the image to enlarge.

In 1999, a sudden wave of nearly 20 million flash memory devices flooded the field, a total that included all the prominent portable formats, like SmartMedia cards, CompactFlash cards, and Memory Stick cards (along with nearly 70 million PDAs, laptop computers, and other hand-held business units that were sold with permanent, or nonremovable, flash memory). Early results from last year point to sales of 25 million or more of these cards, with the industry aiming at $6.5 billion a few years from now, according to the Electronic Industries Alliance, Arlington, Va.

The first removable flash product had been introduced in 1992—the Flash Drive, by SanDisk Corp. of Sunnyvale, Calif. It was the first nonvolatile memory designed for portable computer and consumer electronics products and was devoid of moving parts.

With few software changes until now, the Flash Drive's algorithms were and are like those of a conventional hard disk, intended mainly to store and retrieve documents. The drive even has a standard way to connect to a PC, because it is IDE (Integrated Drive Electronics) compatible. (IDE is a standard interface created by the PC industry to allow hard drives from any manufacturer to work in any personal computer.)

Today's flash memories come in assorted sizes and capabilities. The products range from thumb-sized Secure Digital (SD) Memory Cards, priced at $299 for 256 MB, to the $39 (for 32 MB) business-card-sized SmartMedia card. The SD card can be used in PDAs, microwave ovens, set-top TV boxes, and digital audio and video products. The SmartMedia card shows up mainly in MP3 players and a few digital video cameras.

In one way or another, all the flash types are some variety of electrically erasable programmable ROM (EEPROM) chip that maintains its contents unchanged without need of electric or battery power. The memory cells are laid out in a grid of rows and columns, addressable by bit lines and word lines. Each cell consists of one transistor with an added floating gate that sits between the conventional transistor gate and the channel, and is electrically insulated on all sides by oxide. Data is written by using a process called tunneling to add or remove charge from the floating gate; and since the gate is insulated, the charge remains even when the power is turned off. Different combinations of voltage applied to the conventional gate and the transistor drain determine if an operation is a read, write, or erase.

The spur for flash memory was the need to add storage and telecommunications functionality to laptop computers. Then the rise of digital music and images gave it another boost, because flash was smaller and lighter in weight than comparable magnetic or optical drives. It could fit in small storage slots, keeping the size and weight of the products down. And it is somewhat sturdier than its hard-drive counterparts with their spinning disks.

Besides, for certain applications like downloading and playing digital music files, flash memory cards often have shorter access times than many disk drives.

"Flash memory requires no boot-up or boot-down time, so it is ideal for quick picture taking or fast audio transfers," said Ron Glaz, senior flash memory analyst at IDC Research Ltd., in Framingham, Mass. The cards are also noiseless. And it looks like they'll hold their data a long time—a recent test conducted by scientists from Matsushita of its SD Memory Card at its Tokyo laboratories simulating 10 years of heavy and constant use in a number of hand-held products resulted in no data loss.

But flash memory is pricey, running a dollar a megabyte as against pennies a megabyte for most optical and magnetic forms of storage. Granted, its cost is dropping and its bit capacity is rising fast, doubling almost every six months. But it still lacks the full gigabyte capacity required to run many video and mass storage applications.

Nonetheless, storing 30 minutes of audio or a handful of pictures is well within the capabilities of flash devices, and flash memory was the first way to move these files from camera to PC and back again, or to be of use in two different devices, like a digital video camera and a digital audio player.

When double-density flash chips using multiple-bit cells became manufacturable in 1996, another advance was made. In double-density cells, three distinct quantities of charge (including zero) may be stored on the floating gate, doubling the amount of data stored per cell. It proved possible to store and manipulate not just data but also a small amount of audio and images, said Rick Doherty, president of Envisioneering, a Long Island research and analysis firm. Some of the PDAs, digital music players, and cameras have been further improved—they have been able to reserve a part of the flash memory for encryption, software decoding and encoding, and in some cases the upgradability of the unit itself, amplified Doherty. In other words, these flash chips can keep data secure and negotiate the difference between MP3 and WMA algorithms (MP3 being Moving Pictures Experts Group audio layer 3, and WMA being Windows Media Association).

It's in the cards

Basically, there are five types of flash memory cards and two types of the larger PC cards. Three of the flash types—CompactFlash, MultiMedia and SmartMedia cards—are usually found in digital cameras and music players, cellular phones, and PDAs. Of the other two, Memory Stick, on the market for two years, is making inroads into mostly Sony hand-held products, while SD Memory Cards are the newest.

As for the larger PC memory cards, both types play a solid-state disk role mainly in laptops, but are also gaining ground in hand-held devices. They conform to the standards set up by the Personal Computer Memory Card International Association (PCMCIA), and so, in fact, do CompactFlash and MultiMedia Memory cards—with the help of adapters to convert between different form factors. The PCMCIA Type II card, at 3.2 mm, is thicker than the Type I, at 1 mm, and holds more ICs and more application memory.

PC cards are still mainstays of the notebook computer business, supplying road warriors with add-on modem, global positioning satellite (GPS), and wireless Internet capabilities in newer notebook PCs and some PDAs, too. (In fact, in some older notebook PCs, PC Cards provide up to 2 MB of memory.)

CompactFlash and SmartMedia

Even thinner—by almost 1.9 mm—and now used in hundreds of devices is the CompactFlash, introduced by SanDisk Corp. in 1994, and soon followed by Toshiba's SmartMedia cards.

These two pillars of the flash memory industry differ only a little. CompactFlash consists of a small circuit board holding flash and is more than twice as thick as the younger 0.76-mm SmartMedia card. Its onboard controller uses some of the CompactFlash memory to enhance the performance of the host (say, a camera or music player) and helps administer and monitor power consumption.

According to IDC's Glaz, the CompactFlash onboard controller can increase a product's performance, particularly if it has a slow processor or requires carefully monitored power consumption—both true of MP3 players and digital cameras. The case and controller chip add to the card's size, weight, and complexity, but it is still much cheaper than the SmartMedia card.

In addition to accessing the cards through a PCMCIA port, it is also possible to buy adapters that give access to them through a standard floppy drive or through Firewire (IEEE 1394) or Universal Serial Bus (USB) ports. Or the cards can serve as adapters themselves, to enable the linking of a Microdrive—a miniature optical drive recently introduced by IBM—or other drives to a small device.

CompactFlash cards are 43 mm by 36 mm, and come in two thicknesses: 3.3 mm for Type I, 5.5 mm for Type II. They support dual voltages of 3.3 V or 5 V. SmartMedia cards are about the same size—45 by 37 by 0.76 mm.

Some cellular phones and global positioning satellite (GPS) systems use the tiniest removable card of all, the one called the MultiMedia card. MultiMedia cards can contain single or multiple (depending on the requirements of the application) internal flash or ROM chips and an onboard controller. These cards are dwarves: 32 by 24 by 1.4 mm.

A question of safety

While the Smart Media, CompactFlash, and MultiMedia cards have become a flash memory staple, they lack the built-in encryption needed to satisfy the recording industry's need for security. Nor are they secure enough to be used for sensitive data. Enter Secure Digital (SD) Memory Cards, which do comply with a new standard for protecting sensitive data and multimedia properties.

SD cards mount up to four flash chips and an onboard controller on a card thicker than MultiMedia but the same in area. First announced in August 1999, these cards are only now coming on the market. However, at least 250 companies have agreed to support the SD format, which was jointly developed by Matsushita, SanDisk, and Toshiba.

The cards combine robust storage (256 MB now, 3 GB in testing) with a newly developed encryption system. This feature makes the cards an ideal portable storage system for sensitive financial, medical, scientific, and other uses requiring extra security. The controller embedded in the SD card also provides a secure music transfer agent. It employs the content protection standard that was jointly designed by IBM, Matsushita, Intel, and Toshiba for recordable music.

Consumers can expect "to buy secure music anywhere from a variety of on- and off-line sources and play it everywhere on a wide range of audio devices using SD Memory Cards," predicted Sakon Nagasaki, director of Matsushita's AV Media Card and Electronic Distribution Business Development office in Los Angeles.

This new software now exceeds the requirements of the Secure Digital Music Initiative (SDMI), a group of companies developing technology to protect the copyright of music stored in PCs and transferable to portable devices. SDMI, based in San Diego, Calif., includes companies in the businesses of music content, consumer electronics, information technology, and wireless telecommunication.

On the debit side, an SD Memory costs about a third more than standard flash memory cards—an estimated $200 for a 64-MB SD card versus $150 for a Smart Flash card. Further, products that use the system have been slow to roll out.

Stick it to 'em

Sony Corp.'s Memory Sticks, the first of the so-called super flash type cards, contain flash memory ICs and an onboard controller. Presently the controller is on a separate chip, with advanced Memory Sticks soon providing a one-chip solution, which will mean even faster access and storage. The devices are shaped like a stick of gum, and measure 50 by 21.5 by 2.8 mm.

Sony has the support of fewer than a dozen major companies for this format, used in video cameras, MP3 players, and laptops.

The Memory Stick's biggest handicap is its unusual design. Manufacturers of digital cameras, PDAs, and MP3 players require little redesign to adopt the SD Memory Card because its measurements are close to that of Multimedia cards already designed into previous generations of some products. Memory Stick, on the other hand, fits only slots in newer Sony-backed products.

The spinners

Non-solid-state forms of nonvolatile memory have also combined storage and applications on the same device—a rotating disk. For existing products, like PCs and notebook computers, manufacturers have found ways to convert previously stationary disk storage products into a portable format and done it for more than 1 GB.

Two of the most talked-about products in this arena are Iomega's Peerless magnetic storage system and DataPlay's oft-delayed, but heavily financially backed, DataPlay system. IBM has broached this market with a new version of its Microdrive system.

Due out at press time, the Peerless system is the great-grandchild of the 100-MB Zip and 250-MB Jazz drives from manufacturer Iomega Corp., Roy, Utah. Zip and Jazz were the first mass market removable storage mediums for computers since floppy disks. Over the last eight years, they also were the first drives and disks to be built into new PCs and available to (and backwardly compatible with) older PCs as an add-on peripheral drive.

In contrast, the Peerless drive has transfer rates up to 15 MB/s—nearly twice the rate of a Jazz drive. It also boasts server-sized configurations of 5-, 10-, and 20-GB disks. Those capacities suffice to hold an entire CD collection, thousands of MP3s, and complete libraries of interactive video games. It can also archive computer files.

The drive supports connectivity for both Macintosh and PC, via either internal or external installation. It can also be connected via Firewire, USB, and Small Computer Systems Interface (SCSI) computer connections, so that in the future a user would connect it to a digital TV or personal video recorder like a Tivo or Microsoft Ultimate TV.

Prices for the drive will be under $349, with the Peerless disk running from $129 to $299, depending on capacity. Memory price could go as low as 1 cent per megabyte.

Many users who grew up with Iomega's Zip technology view this new mass storage system as the best way for the company to join and compete in the current storage revolution.

"They sure haven't let time pass them by, the way some companies did," said Arlene Rosenberg, a computer expert with the New York City Board of Education. "This is not your everyday upgrade to an existing product or system—this could be a major contribution to how we move, retrieve, and save our critical data in the next decade."

Big Blue's Microdrive

IBM, incidentally, helped develop some of these mass storage technologies but has not had a lot of success with them in the retail market. The first-generation Microdrive, an optical storage device, for instance, sold moderately well to a limited number of business users, but its price and storage capacity were against it as a consumer product. But IBM may finally have a winner in the second-generation Microdrive.

Due out this summer, the 4-by-3-cm unit uses a 1-GB removable optical disk. Some analysts who have tested it claim that its proprietary data compression gives it almost enough storage space to hold up to 965 high-resolution photographs, or about nine-hundred 200-page novels, or 16 hours of digital audio music. In contrast, flash memory cards with 64-MB storage capacity can store only about an hour's worth of digital music. Most 64-MB flash memory cards cost about $99, or $1.58/MB. The Microdrive costs $0.50/MB. Limited quantities of the new drive will be available in July, with retail shipments scheduled for September. Companies that already have designed, or that plan to design, products compatible with the Microdrive include Acer, Casio Computer, Eastman Kodak, Fuji Photo Film, Hewlett-Packard, Minolta, Nikon, Psion, Ricoh, Sanyo, and more.

Due out about the same time is the newest megabyte mover on the block—the much ballyhooed, but never seen in public, DataPlay system from DataPlay Inc., Boulder, Colo. It is said to be the first of its kind to be both masterable (where the publisher can make the original recording in this format) and recordable by the consumer. Indeed a DataPlay disk could hold a CD's worth of music, video, photographic or computer data in a package about as small as a multimedia card, claimed Steve Volk, the company's founder, chief executive officer (CEO), and evangelist.

According to Volk, the company is hoping manufacturers will deliver DataPlay-based PDAs, music players, digital video cameras, and "unannounced surprises" to retail music and consumer electronic stores by this October. However, many of the third parties listed among its partners, when contacted by IEEE Spectrum, had seen only rough hardware and software specs on the system. With a price of less than $10 for two 1-GB blank disks, DataPlay's detractors are still calling it vaporware.

Still playing near you

Another rotating drive that came under pressure to deliver results is the MiniDisc, from Sony. It is much faster at retrieval than floppies and some Zip and CD drives, yet has been the company's least successful entry of recent years in data and entertainment media storage.

The six-year-old product has been heavily marketed and is now selling moderately well as a pseudo-MP3 player from companies like Sharp. Handicapped by a paucity of pre-recorded music media, it is used in a variety of audio, video, and PC data storage products.

The MiniDisc's single replaceable magneto-optical disk employs magnetic technology to store data and reproduces the audio portion through a confluence with optical technology similar to a conventional CD. The disk has a 2 1/2-inch (6.35-cm) diameter and rotates at 3000 rpm.

With both disks and players priced to this day over 50 percent above some analog and compact disk technologies, and still plagued by a dearth of third-party hardware and software, the MiniDisc had seemed fated to a niche market, of no compelling appeal to either consumers or manufacturers. But a price plunge to under $200 for some models and a heavy push by its entertainment parent, Sony Enterprises, has lifted sales to where it looks as if it will continue to be marketed.

Strictly magnetic is the recent Iomega PocketZip, which is fighting to become both a business and entertainment storage medium. The 2-inch (5-cm) PocketZip disks use a 4-inch (10-cm) player recorder, the HipZip, to read disks storing 40 MB—100 MB by fall. PocketZip is $299 for the drive and $10 per disk. Iomega has included some of the best recording encryption technology, but is struggling to persuade the recording industry to pre-record music in the HipZip format. Plugged into a USB port, the HipZip also saves computer data and moves the data easily from computer to computer, like its big brothers, the Zip and Jazz drives.

Experts suggest that most spinning magnetic storage drive systems created in the last five years have the density to last for at least 7 1/2 to 10 years under moderate use.

The final frenzied factor

And as the flashers try to gain market share from the cards and spinners, analysts predict a surprising turn of events. Rather than drive each other into the storage dump, these products may actually work together.

"Already IBM's Microdrive has a CompactFlash slot on some high-end video equipment," said IDC's Ron Glaz. In addition, the SD Memory Card has been designed to add the functions of storage, connectivity, and applications to other audio, video, and appliances when tethered to them wirelessly or by Firewire or USB, he pointed out.

Still, Glaz sees a very slow road to consumer acceptance as an everyday digital audio, photography, or PDA device. And he is skeptical of DataPlay. "Right now any device, real or imagined, that requires moving parts is destined to drain too much power and to be too costly to build into the existing digital consumer hand-held products," he claimed.

"You are asking manufacturers to add $50 to $250 to the cost of a digital camera, music player, or PDA for some of the drives—HipZip, DataPlay, and MicroDrive—so I am sure that the flash memory in one form or another will be the mainstay of portable storage for a few years," Glaz added.

Tekla S. Perry, Editor

About the Author

RICHARD M. SHERWIN was a syndicated business and technology columnist, then a marketing executive with Philips of North America and Lucent Consumer Electronics, before returning to journalism last year.

To Probe Further

Greater detail on hard-disk architecture is given in the white paper by Steven L. Kaczeus at

For an interesting Web site on compact flash, check out the Compact Flash Association data chart at

Using a search engine such as and typing in "All About Compact Flash" leads to a wealth of information, including that at Also try the SD Memory Card Association product showcase at

Discussions of Sony Memory Stick technology in different products are scattered throughout

The history of Zip drives is presented on the Web site

SanDisk Corp. posts a comparison chart of various memory devices at

For more information on the DataPlay device, take a look at "What's Playing on DataPlay," displayed at


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