The Distributed Virtual Supercomputing workshop was held from June 25 - 27, 1997, in Santa Fe, New Mexico. The workshop was coordinated by Sandia in response to their new ASCI project devoted to distributed computing.

People from Sandia, ORNL, LANL, and a couple of Swiss groups participated. Pretty cool deal: build a big time computational machine using commodity parts. Plan for expansion. Plan for widely distributed computing platforms. Below is a partial description of what was discussed.

Some of the participants:

    Sandia: Bill Camp, Jim Tomkins, David Greenberg
    ORNL: Al Geist, Ken Kliewer, Tim Sheehan
    Swiss: Anton Gutzinger (ETH) and Ralf Gruber (EPFL)
    LANL: Richard Thomsen, Ian Philp, Mike Warren (Omissions are my oversight. Sorry.)

Sandia and ORNL described the type of applications they are interested in running on such a machine.

Sandia folks described their "Computational Plant" project. The '97 goal is to build a 100 GFlops peak/60 GFlops achieved machine. Here are some details:

Hardware (presented by Robert Clay)
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Tentatively:

• DEC chip (433 or 500MHz)
• Myrinet networking boards. Will explore topologies, but a mesh seems the likely candidate in order to allow for easier growth.
• Flexible partition a la ASCI Red: service, system, compute, I/O.
• 1 I/O node per scalable unit (16 cpus?)

• Lightweight operating system kernel (initially linux, then puma/cougar port to alpha)
• Portals for fast communication
• Big compiler effort.
• MPI (details below)

Other stuff:

Heterogeneity (Al Geist)
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Al showed that we have most of the pieces to allow for heterogeneity. They just need to be adapted/adopted/refined. Many presentors/participants shared this view. However, a homogeneous setup will be pursued in the initial phases.

Long distance message passing (Tim Sheehan)
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A collaboration between ORNL, Sandia, and the Pittsburg Supercomputing center involves running applications across widely distributed computing resources. With a lot of work, codes (CTH, LSMS) were executed in parallel on machines located at Sandia and ORNL. For details, see

Many argue that this type of computing is simply a political exercise. Regardless, the challenges involved in computing across the country are related to the challenges involving computing between two machines located in the same room.

Bill Camp: "The alternative to having two major computing resources located at two sites is to locate them both at one site. Which would you prefer?"

Answer: "If they are located at my site, I'm all for the single site model." (My argument for that site being LANL is that the speed of light is faster at altitude.)

A variety of subgroups will be formed in order to attack the multitude of challenging issues that must be addressed/conquered in order for this project to succeed. It could be argued that these issues are not applicable to us rich folk who can afford $150,000,000 machines, but I would counter that it is exactly these types of issues that must be addressed in order to kick us up to the 10/30/100 TFLOP machines, regardless of cost.

Details regarding how to get in on such discussions should appear shortly. Should be fun...

Richard Barrett
rbarrett@lanl.gov
667-6845

What is it?

"It's like a tree. It grows, and is pruned to achieve scalability."
    - Jim Tomkins

"You start with a tree. Then you get a forest. Then you have to deal with a continent."
    - Al Geist

"It's like a cow: we feed it, we milk it, then we slaughter it."
    - I ain't sayin'...

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