[AG-TECH] Scaleable video wall (fwd)

[John Shalf]

We run our AG on our tiled display wall.  We use an Extron switch to  
select between the AG box (a single machine with several PCI video  
cards installed) and the systems that are more tuned for vis (a Linux  
cluster and an SGI multipipe Onyx).  It all works out quite well to  
have a dual-use facility.

We find that using the Extron switch to select between specialized  
systems much more effective than using Xdmx.  With Xdmx, the video ends  
up having to take two hops:  One hop to get onto the system and then  
another hop to push the uncompressed/decoded image out to the correct  
display in the matrix of systems.  As slow as PCI bus is for driving  
multiple video cards, the GigE or Myrinet interconnection fabrics video  
card is even slower with regard to pushing uncompressed video streams  
out to the video cards.  So until Vis clusters be coupled together with  
an interconnect fabric that is *faster* than PCI/PCI-X, the single host  
with a bunch of cards crammed into the PCI bus appears to be the clear  
performance winner (sadly).

-john

On Mar 26, 2004, at 10:47 AM, Steve Gallo wrote:
>
> Hi Allan,
>
> We have both a tiled display wall and AG node (in the same room)
> but haven't really thought of running the AG on the tiled display
> wall.  Since the cost of the tiled display was much more than the
> AG node, I'm not sure that many sites would be able to go that
> route.  Being able to display hi-res images on the AG would be
> a bonus, though.
>
> Steve
>
>
>> -----Original Message-----
>> From: owner-ag-tech at mcs.anl.gov [mailto:owner-ag-tech at mcs.anl.gov]On
>> Behalf Of Allan Spale
>> Sent: Friday, March 26, 2004 11:53 AM
>> To: ag-tech at mcs.anl.gov
>> Subject: [AG-TECH] Scaleable video wall (fwd)
>>
>>
>> Hello,
>>
>> I was just curious to hear if people are thinking about adapting the  
>> AG to
>> tiled displays using clusters of computers for driving the displays.
>> There is an interesting project called Xdmx that runs on Linux that
>> permits a bunch of tiled displays to behave as one cohesive display.   
>> This
>> might renew interest in all-Linux AG nodes.  Imaginge running your AG
>> session and having some high-end viz apps on the same display (or  
>> really
>> hi-res photos :) ).  Using Adobe Acrobat as a PowerPoint viewer  
>> (assuming
>> the PowerPoints were exported to that format), using a Linux-based  
>> tiled
>> display might be an interesting direction for the AG.
>>
>>
>> Allan
>> EVL @ UIC
>> Research Assistant
>>
>> ---------- Forwarded message ----------
>> Date: Thu, 25 Mar 2004 10:45:57 -0600
>> From: Steve Slocombe <s-slocombe at northwestern.edu>
>> To: AG-TECH at mcs.anl.gov
>> Subject: [AG-TECH] Scaleable video wall
>>
>> Hi All,
>> Something way out of our budget, but interesting none the less.  A  
>> scaleable video wall using flat screens
>> with no seams:
>>
>> http://electronicproducts.com/ShowPage.asp? 
>> SECTION=3700&PRIMID=&FileName=HLAP04.MAY2004.HTML
>>
>>
>> Steve
>>
>>
>>
>