While solid state disk drives are by no means a new technology, their evolution is reaching a key tipping point where complete program and data storage can reside on rugged SSDs. This has interesting implications as storage media of significant densities can now reside in slot-card board-level systems or as mezzanines on SBCs.

Military storage implementations used in conjunction with embedded systems have historically fallen into two categories. One is low-capacity, low-performance embedded storage boards. The other is higher-capacity, higher-performance, but physically much larger and heavier external storage boxes or subsystems. However, current flash-based Solid State Drive (SSD) technology—combined with optimized storage controller architectures—has fueled the development of embedded storage blades that provide high levels of consistent performance, reliability and capacity. The latest crop of high-density, rugged solid state storage solutions is enabling military system developers to pack in system complexity without the burden of memory storage constraints.

Parallel to Serial

Just as computing interconnects have transitioned away from parallel buses toward serial interconnect schemes, so too have the interface technologies of the high-density storage realm. That trend is also fueled by the continued dependence on compute- and data-intensive software. With that in mind, Serial ATA has become the dominant interface technology for new storage subsystem designs. SCSI and Fibre Channel in contrast seem to be waning—although far from retreating. Meanwhile, the redundancy of RAID architectures is still a preferred way to ensure reliable mission-critical operations.

An ability to work in extreme rugged environments is a major advantage. TCS’ Galatea SSDs (Figure 1) for example meet the most extreme levels of ruggedness. They also feature AES-128 Encryption with automatic key management and extreme random small-block performance of over 47,000 IOPs. Power hold-up circuitry based on Tantalum capacitors is embedded to ensure reliable performance at high temperatures. These drives fit up to 200 Gbytes into standard 2.5-inch, thin (9.5 mm height) dimensions.

Also targeting the extreme rugged side of the market, SMART Modular Technologies offers a 2.5-inch SATA solid state drive. Called the Xcel-200, the drive delivers performance metrics of 500 Mbyte/s sequential read/write speeds and up to 60K/40K random read/write IOPS. The Xcel-200 is available in capacities ranging from 60 to 240 Gbytes, using highly reliable single-level-cell (SLC) NAND flash. The Xcel-200 was designed and tested per MIL-STD-810 to operate in high shock and vibration applications at industrial operating temperatures of-40° to +85°C. It is also certified for operation at altitudes up to 80,000 ft. 

Small Size Trend

A parallel direction for rugged SSDs is toward compact form factor solutions. With that in mind, STEC extended its enterprise-class MACH16 SSD technology to the embedded market in one of the industry’s smallest solid state form factors. The new MACH16 Slim SATA SSD (Figure 2) provides embedded system designers with the same advanced flash management technology as STEC’s enterprise SSDs. The device leverages industry-standard 22-pin SATA cabling (supporting JEDEC MO-297 and SFF-8156 specifications) and provides the highest data integrity, endurance and reliability available in this market segment. With these features, the MACH16 Slim SATA SSD is well suited for high-performance and rugged embedded systems.

The MACH16 Slim SATA embedded SSD leverages STEC’s patented SSD controller and firmware technologies that help optimize performance, endurance, data integrity and reliability. The device features the same advanced flash management capabilities as STEC’s leading enterprise SSDs. This includes CellCare Technology, which uses a combination of flash management techniques, digital signal processing, ECC methods and other technologies to increase NAND cell endurance and data retention, as well as performance. The drives are available with capacities of 25 and 50 Gbytes. 

Fully Sealed Terabyte NAS System

Today’s military system design is all about compute density and that often means storage density too. Storage systems as fully enclosed units fit nicely into this trend. Along such lines, General Micro Systems offers a fully sealed, rugged, ultra-small, low-power system with Quad Removable SSD. The SX401R-4 (“Depot”) is the industry’s smallest, lightest, total out-of-the-box data logger/recorder that supports all Network Attached Storage (NAS) protocols, and still offers superior performance as a fully functioning computer. It offers 1 Terabyte of data in only 63 cubic inches and 2.5 lbs, with sustained operation never exceeding 20W.

Up to four removable, sealed SSD drives (250 Gbytes each) in the unit are each accessed via SATA or a USB port when removed, which means users don’t need a system to read the data, just a USB cable. Because the drives are sealed, Depot and the drives can be dropped in water as well as withstand the forces of adverse weather conditions, making it ideal for handling by military personnel and critical field operations. Depot is compliant to MIL-STD-810G, MIL-STD-704E and MIL-STD-461F. It is available as a rugged, conduction-cooled and extended temperature (-40° to +85°C) package.

Removable NAS Solution

At the other end of the extreme are the large redundant box-level storage offers. Curtiss-Wright Controls Electronic Systems, for example, provides the Vortex Data Transport System (DTS) (Figure 3), a family of ruggedized DZUS form factor Network Attached Storage (NAS) File Servers (FS) designed for use in sea, air and ground vehicles, field stations and benign laboratories. Easily integrated into Network Centric systems, Vortex DTS servers speed and simplify the integration of NAS FS secure removable storage into military platforms. Applications for the Vortex DTS include cockpit data loader/recorders and data transfer systems.

Vortex DTS file servers provide military system integrators with an easy-to-use, turn-key, rugged NAS FS with optimized interoperability across the product line. All Vortex DTS FSs share a common hardware and software architecture. They feature multiple rugged 128 Gbyte flash storage Removable Memory Cartridges (RMCs). The RMC can be easily removed and installed to seamlessly provide full transfer of data between one or more networks in separate locations. The standard Vortex DTS is configured with three RMCs, with an option for a fourth RMC. Each compact RMC weighs only one half pound and is small enough to fit in a shirt or flight-suit pocket. 

Designed for use in harsh military environments, RMCs are built to withstand extremes in temperature, shock and vibration. To ensure the security of critical data, all data is passed through the DTS inline media encryption module prior to being read or written to an RMC. The DTS encryption capability is modular such that various schemes from no encryption to NSA Type 1 can be developed to meet program requirements. The standard DTS encryption module incorporates AES 256-bit cryptographic hardware that is NIST validated to FIPS 140-2.

Slot-Card Storage Solutions

Particularly in this era of defense budget cutbacks, VME is expected to maintain a steady business of tech upgrade activity. Fortunately, storage solutions based on slot-card VME have kept pace. Phoenix International’s VS1-250-SSD (Figure 4) Serial Attached SCSI (SAS)/Serial ATA (SATA)-based Solid-State Disk VME blade delivers high-capacity, high-performance data storage for military, aerospace and industrial applications requiring rugged, secure and durable mass data storage. This 6U, single-slot module houses one or two each 2.5-inch SAS or SATA SSDs of up to 256 Gbytes per device, and can be interfaced through its front panel connector or its P2 connector. The high-speed module will sustain read/write data rates of 120 Mbytes/s with an access time of 0.5 msec.

The VS1-250-SSD has an operating temperature range from -40° to 85°C and functions at an altitude greater than 80,000 feet. The VS1-250-SSD also complies with current defense department security standards providing multiple levels of secure erase techniques. As a drop-in replacement for a traditional hard disk drive, the VS1-250-SSD offers significantly lower power consumption and eliminates seek time, latency and other electromechanical delays commonly associated with conventional rotating media. The VS1-250-SSD’s performance and versatility is enabled by Phoenix International’s state-of-the-art technology, which provides very high transfer and I/O rates, enhanced endurance and maximum data integrity. A conduction-cooled version of the unit is also available.  

Curtiss-Wright Controls Defense Solutions
Ashburn, VA.
(703) 779-7800.
[www.cwcdefense.com].

General Micro Systems
Rancho Cucamonga, CA.
(909) 980-4863.
[www.gms4sbc.com].

Phoenix International
Orange, CA.
(800) 203-4800.
[www.phenxint.com].

SMART Modular Technologies
Newark, CA.
(510) 623-1231.
[www.smartm.com].

STEC
Santa Ana, CA.
(949) 476-1180.
[www.stec-inc.com].

TCS, Space & Component Technology
Torrance, CA.
(866) 264-0793.
[www.tcsspace.com].