Military mass memory going solid state

Dec. 1, 2000
Despite its high cost, military and aerospace systems designers are carving out a niche market in solid-state mass storage systems because solid-state technology is inherently rugged, fast, consumes little power, and fits in tiny spaces aboard aircraft, ships, and ground vehicles

By J. R. Wilson

The Fast Flash Disk (FFD) from M-Systems is a solid-state SCSI disk based on Flash technology. It can be used as a drop-in replacement for standard 2.5-iinch and 3.5-inch magnetic disk drives with SCSI interfaces.
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Despite its high cost, military and aerospace systems designers are carving out a niche market in solid-state mass storage systems because solid-state technology is inherently rugged, fast, consumes little power, and fits in tiny spaces aboard aircraft, ships, and ground vehicles

Mass data storage for combat systems could be a poster child for overcoming the limitations of commercial-off-the-shelf (COTS) electronics in the harsh operational environment of military action. Two factors are converging to make COTS mass-storage an increasingly attractive option in military and aerospace systems: first, program managers are starting to relax environmental specifications, and second, some new mass-storage solutions are intrinsically immune to damage from environmental extremes.

As a result, military designers are being pushed toward new mass-memory technologies — primarily solid-state memory. The chief advantage of some of these new technologies: they are simply not susceptible to the environmental extremes that could defeat older technological approaches. Solid-state memory, for example, has no moving parts and by nature is far less susceptible to shock, vibration, heat, and cold than are memory systems that rely on spinning media.

Yet sometimes the devil is in the details as systems engineers learn that using COTS can confront them with troubling design tradeoffs. The need for high performance and low cost, as well as minimum weight and size, are more easily met by commercial components each year. Yet in addition each year, those same components tend to drift farther away from the environmental requirements of temperature, vibration, and shock. This inevitably raises concerns about component reliability in real-world conditions.

One problem is solid-state mass-memory technologies tend to be far more expensive than traditional hard drives or the more common tape systems, although the latter also are continuing to see performance improvements.

Of equal concern to systems designers are reliability issues. As environmental requirements are relaxed, testing hardware to strict military specifications, such as a temperature range from -50 to 125 degrees Celsius, is rarely, if ever, done. The military market is not large enough to justify either the testing or production standards that would pass them compared to a civil market that does not need such rugged design.

Creating demand

This has placed the military in what is today the unique position of creating a niche demand for some new technologies — primarily digital mass storage — that are too costly at the moment to attract a large commercial market.

"Aviation is leading the way on digital mass storage," says Ron Burnett, national sales manager for TEAC America's Airborne Products Division in Montebello, Calif. "With the cost of digital, civilian applications are very rare. The military is more interested, regarding the harsh environments in which they operate."

Burnett says designers of ground vehicles such as the General Dynamics M1A2 Abrams main battle tank and the United Defense LP M2A3 Bradley Fighting Vehicle eventually may start using digital mass memory, for example, to record video from new electro-optic sights. Digital recorders also may find use in submarines, long-range unmanned aerial vehicles (UAVs) or unmanned combat air vehicles, he says.

Burnett describes the TEAC solid-state mission data recorder (SSMDR) as "semi-COTS" — commercial design engineered for military applications — and the company's MDR series as a "true COTS" design.

TEAC's SSMDR, he says, is a good example of some of the benefits that military systems designers must weigh against cost factors as they move to upgrade such systems as the Low-Altitude Navigation & Targeting Infrared for Night (LANTIRN) system and the Tactical Air/borne Reconnaissance Pod System (TARPS).

The typical tape transport and electronic interface box weighs as much as 60 pounds, is larger than 2,500 cubic inches in volume, and consumes as much as 450 watts of power. Yet the new TEAC unit weighs less than 9 pounds, measures 8.7 by 6.0 by 3.75 inches (smaller than 200 cubic inches) and pulls less than 50 watts. Its 10,000 hours mean time between failures (MTBF) also far exceeds mechanical recorder systems, which are only as strong as their weakest moving part, Burnett says.

Evolving technologies

Even so, makers of mechanical systems say they believe there is still a place for the next generation of advanced tape drives in the military, especially in static, non-combat roles.

The Targa Series 3 DTU, which is now being used on the B-2 stealth bomber as the primary load device and data transfer unit.
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"The military is a very high-end focus customer, looking for high performance and speed," notes Tom Adams, director of government sales for Exabyte Corp. in Boulder, Colo. "Today's tape technology will back up in excess of 50 gigabytes per hour per drive, so the sheer volume of the data will keep tape alive because it is a very inexpensive way to store a lot of data. I can provide solutions to store data at one dollar per gigabyte, whereas disk drives are basically 100 times that configuration. The disadvantage, of course, is speed. A solid-state solution is very fast, very reliable, and high performance, but it's also very expensive. Even an optical solution, which is faster today, is still more expensive than tape."

New technologies are cutting into some of tape's longstanding advantages, such as the ability to move data physically from one place to another on an inexpensive medium.

"Solid state and these new memory cards probably will supplant tape on many platforms," Adams admits. "And a lot of that also has to do with moving parts — fewer moving parts is better from an engineering standpoint. But the ability to have 60 gigabytes on one cassette the size of an 8-millimeter videocamera cassette is still valuable."

Traditional hard drives probably will be the first complete casualties of new mass storage technology upgrades on combat platforms. Even the best mechanical drives eventually fail, especially in harsh operational environments. But even those competing for that market acknowledge they approach it from an industrial standards position.

"We don't sell militarized products, per se, but our fast flash disk product line, which are semiconductor-based hard disk drive replacements, are rugged enough to meet most military needs," says Chuck Schouw, president of M-Systems Inc. of Fremont, Calif. He says a mass memory system that meets most military needs is able to operate in temperatures of -40 to 85 C, can operate in altitudes as high as 50,000 feet, and has resistance to some shock and vibration.

"These parts are built with standard processes that theoretically can meet MIL-STD requirements, but we don't test them to that level," Schouw says. "Hard disk drives do fail, so we aim our product at mission-critical applications where you simply can't have a failure. Ours go from 3.7 million hours MTBF for 3.5-inch SCSI drives to 5.9 million hours MTBF for 2.5-inch IDE drives. That equates to about 30 years in normal usage."

M-Systems engineers design their solid-state devices to the size and weight of the hard disks the devices are replacing to make them a "drop-in" replacements in the same space. Still, they represent a considerable increase in cost. Today, a 1-gigabyte solid-state drive costs $10,000 or more, a 1-gigabyte flashdisk costs $8,800, a 1.2-gigabyte PC Card costs $5,500 (with a temperature specification of -40 to 85 C), compared to a few hundred dollars for a 10-gigabyte hard disk and even less for equivalent tape storage.

The 48-gigabyte SEAKR tape and rigid-disk replacement system replaces hard drives and tape.
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"I think it will be a long time coming just do to the cost involved," Burnett says of the prospect of solid state supplanting tape. "The media cost is very high compared to tape. For example, a $10 tape can record two hours of video, where the same capability in solid-state memory would cost about $16,000 to $20,000. You can get a lot of tapes for $20,000 — and you can run the same tape 50 to 100 times, depending on your environment. Of course, you can use the memory cartridge 100,000 times before needing to replace it, but that would be a couple of hundred years of use, which isn't likely to happen."

Schouw is more optimistic. He says he believes speed and capacity requirements will negate the cost difference, especially as solid state prices continue to decline.

"The military has finally come to understand they need to use solid state and get away from mechanical hard disk drives," he says. "So the market is expanding because of that. Processing power is becoming more and more an issue and as those needs go up, so do the needs for capacity and speed. In-flight data recorders, moving maps, fire-control systems, and image recording are the primary military applications we're seeing them used in. The higher speed and capacity lends itself to video imaging, as well as any kind of high-speed numbers crunching."

Schouw says the price per megabyte of solid-state mass memory will go down as speed and capacity goes up because manufacturers will take advantage of the latest flash chips on the market. "We will get the benefits of the semiconductor learning curve. The drive itself, as it gets bigger, will cost more, but the cost per megabyte will be less," he says.

Phoenix International of Orange, Calif., run by the father/son team of Amos Deacon Jr., CEO, and Amos Deacon III, vice president of sales and marketing, is another provider of solid-state hard disk replacements using flash memory.

"We provide a solid-state disk that looks like a hard drive to the host but is actually made up of flash memory," says Amos Deacon III, who also serves as the company's technical spokesman. "That typically is used as a very fast cache in front of the disk drive, although it also can been used now as a storage device at the gigabyte level. It is extremely rugged and has environmental characteristics that are very important for spacecraft or submarine applications, for example."

While agreeing cost has inhibited the technology's desirability in the past, Deacon also notes solid-state drives have dropped in price by a factor of four in recent years, a trend he expects to continue.

The dropping prices of solid-state drives have "opened up more applications for it anywhere there is high shock or vibration or extreme temperatures," he says. "It also is very small in size; we typically have it in the same form factor as a 2.5 inch disk drive used in a notebook computer."

Also looking to supplant standard hard drives and tape with solid state is SEAKR Engineering of Englewood, Colo., which offers its Tape and Rigid-disk Replacement System (TARRS) in configurations from 12 to 96 gigabytes.

"This product is typically slated for airborne data acquisition and storage requirements, primarily for the reconnaissance community," says Randolph Twogood, SEAKR's director of military electronics.

SEAKR's product is a DCRSI emulator, which operationally can fulfill applications that require data to be removed from an aircraft. "We offer a rapid remove and replace approach, where the entire recorder is removed from the airframe and taken to a data center for analysis," Twogood says.

SEAKR's second approach is a removable memory unit (RMU), which enables users to remove the memory from the recorder and replace it with another fresh RMU. Then users can take the removable cartridge to a ground support station for analysis, Twogood says.

The company's third approach involves "a concept we pioneered in 1997 called the data transfer system (DTS)," Twogood says. "The DTS is taken to the flight line and connected to the data recorder [it has its own power system, so the aircraft does not need to be powered up]. We transfer data from the solid-state data recorder using a Low Voltage Differential Signal (LVDS) interface at 100 megabytes per second. The next generation LVDS will double the throughput."

Evidence of the anticipated future growth of solid-state devices is in the number of companies, such as Targa Electronics Systems Inc. in Charlotte, N.C., that deal exclusively in flash disk drives, memory cards, and similar devices.

"As the commercial capacity of PC cards grows, the military will be able to buy that capacity without incurring additional developmental costs," says Targa marketing vice president Joe Fronsee. "Today, you can get up to 1.2 gigabytes on a PC Card and by early 2001 that will be doubled. The speeds of flashdisks today are faster than regular rotating hard disks, which is a significant turnaround; initially, they were slower. Today, flashdisks have sustained continuous read or write speeds of more than 9 megabytes per second."

Flashdisks are particularly appropriate for airborne applications because these applications rarely have temperature limitations, as do rotating disks do, and because flashdisks withstand shock and vibration much better than do rotating disks, Fronsee explains. "We have flashdisk drives in a lot of airborne applications, such as the development and test stage of the NASA X-38 space station personnel escape vehicle," he says.

Packaging is an important element in determining which technology is best for any specific application, especially when cost restrictions make the less environmentally capable mechanical systems more attractive, experts say.

"The primary starting point in the environmental characteristics of all our systems is the intrinsic capability of the device itself," Deacon says. "For example, a HD drive has better environmentals than a tape drive. Our package actually enhances the environmentals, but unless we do something extra special, that's as far as we go. Everything we do is COTS."

Phoenix offers a nine-bay chassis that is certified to a telecommunications standard called NEVS. "It's a very robust design that will take a million volt lightning scale and continue to operate at 10 on the Richter scale," Deacon says. "Everything is dual redundant, with no single point of failure. That's what I mean by 'package'. We take whatever disk drive we think is the best available; if we use something specified by the customer, we point out they get the capabilities of their choice."

Many storage systems chosen for high-performance, high-capacity military and aerospace applications are based on the VME or Compact PCI circuit card format and backplane, and use either a SCSI or FibreChannel interface.

"The VME and Compact PCI buses are incredibly fast and go into very small packages," Deacon says. "And VME is always backward compatible. We even have one of our VME hard drive modules going up on the space station. It isn't an enormous market — maybe $2 billion to $3 billion worldwide — but it is very high end, very elegant, and is heavily utilized by the military for such things as all of the tactical data systems."

The role of DVD

Digital video disk (DVD) and CD-Writable drives also are going into some military mass storage applications. Users can set up several different DVD drives in libraries, with hundreds of disks accessed by a robot. An old tape library system at Lockheed Martin Missiles and Space in Sunnvale, Calif., was replaced by a DVD library, for example.

"The benefits of going to a DVD system in an archival situation are much longer life expectancy for the media, which also is non-linear [the head can read anywhere on the disk almost instantaneously, opposed to fast forwarding and rewinding a tape] and the media are much smaller," Deacon says.

Even with new technologies available, there is an enormously large base of legacy mass storage systems throughout the military that work and are not wearing out. These systems represent not only hardware, but also a significant investment in software that would be extremely expensive to rewrite. Given tight budgets and more pressing needs elsewhere, the odds are legacy mass storage will not be replaced en masse in the near future.

Nonetheless, industry experts believe they can make some solid arguments for selective replacement.

"If someone has a big bank of old rotating tape drives and a lot of material archived, they can convert that into a DVD library, it just takes time," Deacon says. "It comes down to cost/benefit. Some of those huge old tape drives can be replaced with current technology at much less in terms of power and maintenance, often enough to pay for the new system. That opens a few eyes."

Environmental concerns often make solid state the medium of choice

Solid state mass storage providers find themselves fighting an age-old battle for any new technology: It may be faster and smaller (physically — larger in terms of storage capacity), but it is anything but cheaper.

Today, solid state costs hundreds of times as much as tape or mechanical hard disks for the same storage capacity. And while that cost has been on a dramatic downward curve, it will never match the per-gigabyte rate of those older technologies.

SEAKR Engineering's 6-gigabyte bulk memory module single-slot VME module.
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On the other hand, environmentally, a solid-state device is more robust than any mechanical device — tape or disk — because it has no moving parts. As a result, it could be more ideally suited to the harsh environments of many military applications.

And despite tight budgets, the ability to process, store, and forward a wide range of data quickly and efficiently is becoming more and more important. The higher the performance from sensors, for example, the higher the data rate requirement. Recorders also are becoming more of a hub than a single-purpose device, and must handle audio, video, sensor, and systems data, with compression and near-real time in-the-loop capability.

"Solid state provides some technology enhancements a tape system does not allow you to do, including random access, truncating buffer capability, a much higher rate of data scan, and the ability to go to an immediate address," says Randolph Twogood, director of military electronics for SEAKR Engineering of Englewood, Colo. "From a reliability perspective, over the lifecycle, because tape systems are mechanical in nature and a solid-state device has no moving parts, the lifecycle costs will be much less for solid state than tape."

What defines mass storage is not volume itself, but the ability to store all of the data required for a specific application. On a digital camera, for example, a few gigabytes would qualify as mass storage, while library archives are often measured in terabytes.

M-Systems Inc. of Fremont, Calif., offers flash disk mass storage, with built-in processors, at the lower end of the scale — 2.5 and 3.5 inch SCSI and IDE drives with capacities ranging from 32 megabytes to 2.4 gigabytes. In these sizes, speed is often more important than capacity; for the M-Systems drives, that ranges from 2 megabytes per second sustained write and 2.8 megabytes per second sustained read on the 3.5 inch SCSI to 3.4 megabytes per second read and 3.6 megabytes per second write for the 2.5 inch SCSI.

"We have a new product coming out — 3.5 inch SCSI, RISC-based — that has a sustained write of 18 megabytes per second and read of 22 megabytes per second," says M-Systems president Chuck Schouw. "It is being targeted for video applications. Engineering samples will be shipping by the end of the year, with production units available in the first quarter of 2001."

He says the M-Systems 3.5 SCSI will go to 11.5 gigabytes later this spring, the 2.5 IDE to 4.9 gigabytes and the 2.5 SCSI to 5.4 gigabytes. The new high-speed 3.5 SCSI will come out at 2.6 gigabytes and will grow to 5.1 gigabytes by this spring. It is set to go to 10.2 gigabytes by mid-2001.

"We expect to continue to increase speed and capacity," Schouw says. "We're limited by the size of the flash devices available and by the physical envelope of the unit, but, in theory, we could continue to double capability every year or so." He notes the earlier versions already have been designed into HMMWVs, tanks, landing craft, and other rugged-environment applications. "With more and more sensors, the military probably can use more and more storage, so I really don't see a limit to it."

The use of solid-state storage devices is increasing across a broad band of military applications, usually replacing slower, less robust mechanical systems. But a technology mix is likely to remain in place for some time, experts say.

"Will solid state completely replace tape? Within five years, probably not," Twogood says. "I would suggest that at some point the technology of tape will become obsolete. So by simple evolution, at some point down the road, it will be replaced, but that is many years away. During that time, because of obsolescence issues, tape products also will probably become more expensive." — J.R.W.

Tape memory technology steadily improving

The kind of tape drives now available for military applications, from static library archives to real-time combat platforms, represent significant technology advances over previous generations of tape drives.

"Our new Mammoth 2 tape drives give very high throughput; each drive exceeds 12 megabytes per second transfer rate, which is screaming fast in the tape world," says Tom Adams, director of government sales for Exabyte Corp. in Boulder, Colo. "Each library can hold up to ten drives, which gives a lot of bandwidth.

The 50-gigabyte TEAC solid-state mission data recorder is for aircraft applications.
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"We're involved in a number of military programs that back up Microsoft Exchange servers, including a lot of e-mail backup," Adams says. "The U.S. Air Force, in conjunction with TRW and EDS, has put together worldwide backups to the Microsoft Exchange servers on all airbases, including the Air National Guard."

One of the biggest changes for tape has been search capability. Traditional drives have required a search to begin at the start of the tape. The recent inclusion of partitioning, which can divide a tape into up to 260 segments, has made it possible to start anywhere.

"That is where software management really comes in," Adams explains. "You first go to the software to find out where the file is," Adams says. "In the future, the software will have partition addresses as well as file addresses, which will bring the search time down even more. And that makes us more competitive in terms of time. But you can't do it without software, which is very important to us, long term."

And therein lies the problem, according to tape systems manufacturers — the greatest improvements are yet to come, if they can get programmers interested.

"There's a lot of room for improvement in data management on tape, probably a five- to ten-fold increase in performance once the tape manufacturers and data manipulators come together and not only design their software to maximize the proficiency of the tape drives and data on tape but also to take the best advantage of the hardware design," Adams says.

"So far, no software company has even tried to take the best advantage of all the capabilities of the new tape drive technologies," he says. "Their job is to manage the data, which is a whole world unto itself and a very difficult job, so they haven't spent the time to try to understand the mechanics of tape technology. In truth, they don't care. So it is up to the tape manufacturers to work closely with the software companies to achieve that, but about as far as we can go is to build toolkits to help them."

He says it should be possible to access a data file anywhere on a 60-gigabyte tape in 10 seconds, "but it will take a lot of hard work."

Major technological improvements also are being made in the hardware. Ten years ago, a 160-meter tape would only hold about 2.5 gigabytes of data; today, it holds almost 50 gigabytes. That is because of such improvements as an advanced metal evaporative media and new head constructions on the drives themselves.

These faster, higher-capacity tapes also are for more than just data storage, including plans to port data, video, and audio to the same tape aboard jet fighters. Such tape systems would offer variable-speed manipulation tailored to the type of files being stored. Yet handling those tasks in the extreme environment of a jet fighter is going to take careful engineering, tape proponents acknowledge.

New communications modes, beyond SCSI and UltraSCSI, also are adding to the speed of tape systems. Fiber optic connections, for example, enable users to configure systems by plugging fiber switches and hubs directly into tape drives. This helps large networks of people communicate to individual tape drives in that network without a server managing that protocol. — J.R.W.

General Dynamics offers 18-gigabyte rugged disk drive for combat aircraft and ground vehicles

BLOOMINGTON, Minn. — Mass memory systems designers at the General Dynamics Information Systems division in Bloomington, Minn., are offering a new rugged disk drive, the RMS-1018 removable memory system, for use in severe-environment platforms such as tactical aircraft, surveillance pods, unmanned vehicles, and armored combat vehicles.

The General Dynamics RMS-1018 removable memory system is for use in severe platforms such as tactical aircraft, surveillance pods, unmanned vehicles, and ground mobile systems.
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The RMS-1018 disk provides 18 gigabytes of user storage in a rugged, sealed, pluggable cartridge. Using a FAST SCSI II interface, the RMS-1018 disk is for applications such as recording, file serving, digital map storage, or data buffering.

Company engineers tested the RMS-1018 disk to survive repeated drops from 30 inches and still operate reliably.

"Disk storage has continued to improve in ruggedness allowing it to be used in situations not dreamed of a few years ago," says Thomas Rent, a senior systems engineer at General Dynamics Information Systems. "We have flown our disk drives with great success in high G and high roll rate conditions on fighter aircraft, and have hundreds of our drives operating everyday in both U.S. and foreign tanks."

The RMS-1018 disk can operate at altitudes as high as 70,000 feet, in temperatures from -54 to 71 degrees Celsius, and in shock and vibration as strong as 125 Gs without external shock isolators, General Dynamics officials say.

The unit weighs 3.4 pounds, and uses less than five watts of power allowing it to be used in systems powered by batteries, such as mobile/backpack systems.

For more information contact General Dynamics Information Systems by phone at 952-921-6000, by fax at 952-921-6869, by post at 8800 Queen Avenue South, Bloomington, Minn. 55431-1996, by e-mail at [email protected], or on the World Wide Web at — J.K.

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