Using stable, reliable systems for mission-critical video walls
Ken Lin, Advantech
2/6/2013 12:45 PM EST
As mentioned, computers supporting video wall applications are no ordinary computers. A reliable, powerful dedicated video wall controller has to deal with the following problems from the design level:
(1) PCIe bandwidth and data switch rate provision
When images on a video wall are enlarged, reduced or moved across multiple monitors, it requires huge transient video data transfers between and among multiple Mura MPX cards. Especially for a dense system in a large scale video wall application, there can be many data inputs and outputs in combination, and data exchanges among these inputs and outputs are extraordinary. For example, a 1080p full HD video stream generates 0.5 GB/sec data throughput; when four such video streams are captured by a MuraTM MPX card and displayed through four output ports on a different card, a 2.0 GB/sec card to card (slot to slot) data transfer occurs. A video wall controller’s PCIe slot design must have not only enough bandwidth but also a data switch rate that ensures quick, smooth, no-latency display.
Because in most application scenarios a video wall controller needs to carry more than two Mura MPX cards, all Advantech AVS products are designed with server grade chipsets to have enough PCIe lanes from the CPU and high data switch rates between PCIe slots. Every PCIe x16 slot supports at least Gen 2.0 PCIe x8 bandwidth; BIOS is also tweaked to support multiple GPUs (a MuraTM MPX card can have up to two GPUs) and to maximize card-to-card transfer rate.
Advantech sends all video wall controller prototypes to Matrox headquarters in Montreal, Canada for validation; this ensures rock solid compatibility. Advantech video wall controllers driving Matrox cards can power video walls up to full 1080p inputs and outputs with zero latency.
(2) Thermal design
When multiple graphic cards are employed in a computer system to drive a multiple monitor video wall, the power consumption is huge and there rise system heat problems that need to be carefully dealt with in both board and system design levels. System cooling performance relies on the selection and installation of fans and efficient air flow design in the chassis.
Ordinary computer motherboards have their memory sets be positioned horizontally, perpendicular to CPU, PCIe expansion slots and other components on the board. This is to facilitate more economic PCB wiring, as PCIe traces can be more conveniently routed to the CPU.
However, when it comes to a dense system supporting video wall, ventilation becomes the priority. Advantech has employed a component placement call Rack Optimized Placement which places the memory slots parallel to PCIe slots on the motherboard in order to maximize the efficiency of the chassis airflow and cooling performance, effectively lowering CPU, memory, motherboard major ICs, Mura MPX GPUs’ temperatures to keep system very stable when operating with multiple Mura MPX cards. This poses challenges for PCB wiring and forces us to employ more PCB layers to complete needed wiring.
This is one of the reasons why a video wall controller is usually more pricy than other IPCs or ordinary computers. However, the price tag is worth it as system shutdown or failure due to overheat could be catastrophic in mission-critical applications.
(3) Remote management capability
Remote control and monitoring is also an important part for maintaining system health and operational reliability. When a computer system is going awry, abnormal signals will surface first in temperature, voltage or fan rotation speeds. Remote management allows operators to get their hands on all these figures related to system health via network connection. This feature is especially important for a video wall administrator because the video wall controller is usually put in the computer room where the operator usually does not seat in.
In addition to using a remote computer to access the video wall controller, operators can also use smartphone, iPad or laptop to monitor system status. When operators find the voltage in the system becomes unstable, temperature is rising or the fan rotation is slowing, they can immediately take actions to repair, and if in time, they can avoid a catastrophic system failure.
The remote management capability has almost become heritage for server-grade IPCs, especially for those used in critical missions. Many of these systems can automatically issue local alarms, send alerts or notifications to operators through e-mail or cell phone message when any abnormal situation is happening in the system.
There are technological or business options for remote monitoring and control: either software-based in-band solutions which operate utilities or application software under operating system like Windows, or hardware-based out-of-band solutions such as IPMI or iAMT that are enabled by a separate BMC circuits on motherboard or embedded controller inside Intel PCH chipset to allow remote administrators to have access to it regardless of whether the system power is on or off, in a dormancy or is failed. With out-of-band solution, administrators or operators can start, shut down or restart the system remotely; even when the system is powered off or the OS is dead, as long as that small unit is still “alive”, the operators can get access to that unit via the Internet to understand the status of the system.
Obviously, the software-based solutions are more economically appealing. The SUSI-Access remote diagnosis software developed by Advantech is even free and available for all its customers. However, for video walls used for mission-critical applications, hardware-based IPMI or iAMT solutions are strongly recommended.