Server stacks boards

Over the past decade, the PC architecture has become an accepted platform for far more than desktop applications.

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Over the past decade, the PC architecture has become an accepted platform for far more than desktop applications. Dedicated and embedded PCs are used as controllers within laboratory instruments, communications devices, and medical equipment.

"By standardizing hardware and software around PC architecture, embedded-system designers can accelerate development with reduced costs and risks, resulting in faster time to market," says Andrew Buglass, Active Silicon product manager (Uxbridge, UK; "Therefore, companies that embed microcomputers as controllers within their products seek ways to reap the benefits of using the PC architecture. However, the standard PC bus form factor (12.4 × 4.8 in.) and its associated card cages and backplanes are too bulky (and expensive) for most embedded control applications."

PC/104 and the PC/104-Plus specifications were developed in response to this need. The standards are particularly suited to embedded applications, offering full architecture, hardware, and software compatibility with the PC ISA bus, but in ultracompact (3.6 × 3.8 in.) stackable modules. Incorporating the PCI bus within the industry-proven PC/104 form factor, PC/104-Plus is a PCI-enhanced version developed by Ampro Computers (Sunnyvale, CA, USA;

Using the PC/104-Plus standard, Active Silicon has integrated an off-the-shelf frame grabber, CPU, and Ethernet board in its active video server. The server offers a means to capture, process, and communicate information and data from up to four cameras. This system is built from a stack of PC/104-Plus boards, comprising Active Silicon's LFG frame grabber, a processor board, and a wireless Ethernet board. "In the design of the product," says Buglass, "we chose to use Debian Linux ( because it can be customized for embedded systems and run as a read-only file system with wireless capabilities."

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Using its own PC/104-Plus frame grabber and off-the-shelf CPU and Ethernet cards, Active Silicon embedded video server is targeted at remote wireless video-monitoring applications.
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Reliability has been addressed through the use of a 300-MHz fanless CPU and a solid-state flash file system, so there are no moving parts. The software runs from a read-only CompactFlash-based file system, allowing the unit to be power cycled at any time without corruption.

At the heart of the system is a TP400B processor board from DSP Design (Chesterfield, UK; Based around the AMD (Sunnyvale, CA, USA; Geode GX1 MMX enhanced processor, the processor board has the standard PC/104-Plus footprint and built-in wired Ethernet.

Wireless Ethernet connectivity is provided though a PC/104-Plus PCMCIA adapter board from Aaeon Electronics (Limburg, Germany; and a wireless Ethernet PCMCIA card from Cisco Systems (San Jose, CA, USA; "This PCMCIA interface," says Buglass, "provides the flexibility to use different types of wireless Ethernet cards depending on the application."

Although the unit has many potential applications, the initial key target is wireless video security in areas requiring high reliability. The first major application has been in passenger aircraft security, for which the unit is currently undergoing US FAA trials for approval. To satisfy this area, Active Silicon has developed a complete video Web-server application, allowing images to be viewed remotely using 128-bit encryption over a wired or wireless Ethernet connection. Beyond the security markets, the company expects the video server to find uses in areas such as remote monitoring or adding vision to emergency vehicles.

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