Lee Brown, Curtis-Wright Controls Defense Solutions, Mil-Embedded.com

Network Attached Storage allows system designers to take advantage of increased security, storage and better SWaP mitigation over direct attached storage alternatives.

The pervasive use of standard network fabrics such as Ethernet on military platforms has joined with recent cost and density improvements in solid-state non-volatile memory, fueling significant growth in demand for Networked Attached Storage (NAS) devices the past couple of years. On today's military platforms, on the ground and in the air, the use of Ethernet to connect various parts of avionics architecture or crew stations, smart displays, and controls to the platform's local network has become nearly ubiquitous. System designers have found that Ethernet enables them to easily attach devices together over the network. Once networked, the platform's subsystems can take advantage of the high-speed, high-volume data storage; Space, Weight, and Power (SWaP) mitigation; and enhanced security options that NAS makes possible compared to direct attached storage alternatives.

NAS: Flexible storage in net-centric environments

Today's devices are incorporating network connectivity as system designers embrace net-centric architectures. Legacy subsystems built with older technologies – such as RS-232, 1553, and CANbus – are being bridged to Ethernet so they can communicate with other systems on the network. Now, using NAS, designers can more fully exploit the Ethernet-based LAN to centralize data storage that was formerly available only to individual devices through direct attached devices. While direct attached storage devices enabled system designers to dedicate private storage of the speed and size required by each particular subsystem, NAS provides the significant advantage of supporting easy and dynamic reallocation of available system memory. With NAS, if a new system requires storage capacity, the needed memory can be easily allocated from existing memory without incurring the additional cost, weight, and maintenance of a new storage device.

NAS benefits: Security, version control, and SWaP

Another significant advantage of NAS over direct attached storage is that NAS enables easy removal of stored data, especially classified data, so that it can be protected remotely when the platform is not in operation. Direct attached stored data is located throughout a vehicle, making it difficult to remove for security purposes. With NAS, the user can remove individual cards or the entire NAS box. To further ensure data security, today's NAS devices also incorporate encryption technology, such as 256-bit Advanced Encryption Standard (AES) encryption. Vendors such as Curtiss-Wright Controls Electronic Systems (CWCEL) are also incorporating secure-erase technology to zeroize the encryption key on the NAS device that causes the data to become declassified as it can no longer be decrypted. This approach allows terabytes of data to be sanitized within milliseconds, versus the many hours it could take to zeroize terabytes of solid-state memory data.

NAS devices ease software configuration control because the entire platform's processing elements boot from the NAS. The use of standard protocols enables all of the platform's processing systems to boot from a common storage device. The boot software and related binary programs can be loaded onto a single box, ensuring any system software updates occur simultaneously. This eliminates the risk of any single device getting updated while others are overlooked.

The need for SWaP mitigation also makes NAS attractive to military system designers. By packaging the solid-state storage into rugged, high-bandwidth 3U VPX modules within the storage device, lightweight compact NAS devices can be built. CWCEL offers the Compact Network Storage (CNS), a very compact, half-ATR-wide NAS device. It deploys one-half TB of memory on 3U VPX cards such as the VPX3-FSM (Flash Storage Module). The use of solid-state memory eliminates rotating disks' susceptibility to shock and vibration.

Solid-state memory densities rise as costs drop

It is only recently, though, that the cost of solid-state memories has made this approach economically practical. The cost of 500 GB of solid-state memory has dropped from $1 million (with 80 MBps throughput) to $35,000 (with 800 MBps throughput) in just seven years. Furthermore, that same 500 GB once required a full ATR-sized box, but today can be deployed on two 3U VPX-based cards.Asmemory density increases, it will be possible to deploy much more storage in the same footprint. For example, the CNS 0.5 TB is expected to increase to 1 TB by the end of the third quarter of 2010. With the higher-density networked storage made possible with NAS, system designers can capture and store more information – such as streaming data – than was possible before.

To the user, the NAS appears as a local drive on the system. Because NAS operates as a standard file server, it runs standard operating systems and major network protocols. It facilitates network architectures in military platforms in a way not possible with direct attached storage. It provides access to many network standards and communications mechanisms, bringing state-of-the-art networking into vehicles.

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