Technology Focus Solid State Drives
Flash Drives Take Over Rugged Storage Solid state flash drives are winning the battle for attention from military system integrators, due to their ruggedness, reliability and ease in protecting sensitive data. Ann R. Thryft Senior Editor
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lash solid state disks and drives are becoming the medium of choice for high-performance, reliable, rugged, secure storage in military environments. As the number of embedded computers in military electronic systems keeps rising, so does the amount of data that must be acquired, processed and analyzed. But that data is also becoming increasingly sensitive and subject to theft or falling into the wrong hands. Depending on which military platform is involved, the operational needs of data storage systems—and the media they use—can differ. Ground systems, such as combat vehicles and tanks, must withstand high temperatures up to +85°C or more, as well as shock and vibration. Aircraft such as fighter jets, for example, require the ability to operate in high-jerk environments and 10g linear acceleration (Figure 1). MIL-STD 810F defines specific operating requirements. These are a temperature range of -40° to +85°C, a humidity range of 5% to 95%, altitudes of up to 80,000 feet, shock conditions of up to 1,500g half-sine and random vibration of up to 16.3g (10 Hz to 2,000 Hz).
New Interfaces, Form-Factors The optimal mix for each platform differs somewhat, but they all have in common the need to handle more data faster, more reliably and more securely. For storage systems, this means larger capacities, faster sustained transfer rates, more rugged hardware and the ability to quickly erase or even entirely destroy the data. It also means a growing variety of interface options. As standard interfaces multiply for hard disk drives, they are also becoming available for flash solid state drives (SSDs). They enable easy data transfer to commercial computers and allow standard computer backup practices, enabling lower-cost solutions. Fibre Channel, SCSI, SATA, IDE and Ethernet have become common. Fibre Channel, for example, is a favorite of military engineers because it provides high-reliability, continuous operation and flexible location, requiring only lightweight cabling. Flash SSD form-factors are also expanding. This year’s crop of SSDs includes CompactFlash, VME modules and PMC/XMC cards. Flash SSDs on PMC cards, for example, can take advantage of the PMC slots typically available on rugged embedded boards and the small PMC form-factor is naturally rugged. Flash [ 46 ] COTS Journal December 2006
Figure 1
The inherent ruggedness and reliability of solid state flash drives, as well as the ease of securing their data, make them ideal storage solutions in many high-performance military designs. Flash drives are found in a growing number of military environments, including aircraft, and many operate at up to 80,000 feet. The U-2 high-altitude multi-intelligence reconnaissance aircraft flies at 70,000 feet or higher, providing nearreal-time imagery and signals intelligence to warfighters and national authorities in support of Operation Iraqi Freedom. Photo by Staff Sgt. Matthew Hannen, Courtesy of U.S. Air Force
chip density is now high enough that a PMC can store an OS and performance is high enough to rival that of hard drives. When it comes to security, flash SSDs outperform hard drives hands down. Flash SSDs can erase data on the media before it is reused, either protecting the data (clearing) or not protecting it (sanitizing) first. They can also damage the media physically so that data retrieval is impossible (destroy), and all three types can be performed at the push of a button. Hard drives, by contrast, require large, heavy, power-hungry degaussers that are susceptible to operator error and that cannot be used quickly in emergency conditions. As flash memory prices continue to decline, so does the price of flash SSD media, promising a lower total cost per recording system than the cost of traditional hard drives.