From: poser@vxdsyc.desy.de (Till Poser)
Subject: Re: Supercollider "For" or "Against"
Reply-To: Poser@vxdsyc.desy.de
Organization: Deutsches Elektronen Synchrotron, Experiment ZEUS bei HERA
Date: Mon, 27 Jul 1992 15:12:06 GMT

In article <01GMUWFKMPZK001FEW@utarlg.uta.edu>, B645ZAW@UTARLG.UTA.EDU 
(Stephen Tice) writes:
|>I may type in a fuller treatment of the data-handling problem later in
|>the week. {Mr. Austern, will also want to take note.} I said that the
|>figure being "bandied about" is a "Terabyte per nanosecond," and

In all the below kvetching I fail to see how You arrive at the Tbyte/ns
figures.

|>submit the following teasers. From the Conference Record of the 1991
|>IEEE Nuclear Science Symposium and Medical Imaging Conference, Nov.
|>2-9, 1991, Santa Fe, New Mexico, USA, vol 2 of 3...
|>
|>  "Data Acquisition Studies fro the Superconducting Super Collider"
|>  by Milner, Booth, Botlo, Dorenbosch, and Wang of the Physic Research
|>  Division of the SSC, and Idate, Kappor, and Raj of the University of
|>  Texas, p. 929:
|>
|>    The collider will provide a beam crossing every 16 ns, with a mean
|>    of 1.6 collisions per crossing (100 mb cross section) occuring at
|>    the design luminosity of 10^33 cm^-2 s^-1, giving a 100 MHz inter-
|>    action rate. We can expect data for each event to be about 0.4
|>    Mbyte, giving a raw data rate of 40 Tbyte/s...

So what? In an earlier posting I gave a rough estimate of 300 TByte/s, 
which is definitely not unmanagable. The above figure is just a factor of
5 ~ 10 larger than ZEUS'. Where is the problem?

|>Perhaps Doctor Hallam-Baker would care to translate that, or he might
|>wish to refer to another paper from the conference...

Or Phill can just leave it. This googolplex bytes/femtosecond business
is not really a big focus. The key here is the phrase data locality, 
i.e. the parallelism of the data reduction, and the phrase data reduction.
The final output will be determined on how fast the "interesting physics"
can be recorded on mass storage. That's about 2 Mbyte/s for ZEUS, i.e. an 
event rate of 10 Hz. 

|>  "High Speed Data Transmission for the SSC Solenoidal Detector," by
|>  Branko Leskovar of Lawrence Berkeley Lab, p. 828:
|>
|>    ... Using an open architecture, the data acquisition system will be
|>    capable of processing data rates of several thousands Gbit/s from
|>    detector elements to the online processing system....

Still a far cry from You fraudulent Tbyte/ns. How about corroborating that 
statement, instead of waffling?

|>
|>And rather more amusing, though no less thought provoking, was the article
|>out of COMPUTERWORLD from (7-31-89), "Collider's colossal computing
|>conundrum," p. 4:
|>
|>    ...The lab expects 100 million collisions per second.
|>
|>    ..."Each time particles collide, something happens. But it's not
|>    necessarily something you're interested in," Gilchriese said.
|>    [Gilchriese was then associate director of the physics research
|>    division of the supercollider lab.] He said he expects reductions
|>    to be made from 100 terabytes "to 10, or 100 [megabytes] at most."

Still no Tbyte/ns. The 10-100 Mbytes figure is, I guess, the amount of
data he expects to be able to write to mass storage.

|>    No on yet knows how that filtering will be done. Artificial
|>    intelligence programming will not fit the needs of filtering
|>    information, although it can be used in machine control. Gilchriese
|>    said the lab's researchers were exploring neural networks to make
|>    heuristic decisions....

Did You understand what this gentleman has been trying to tell You?
The only thing that I see here that Gilchriese admits that there are no
readymade data reduction and trigger algorithms and methods, that fit 
immediately. Ho hum! So what else is new? This requires quite a bit of
simulation of machine and detector and the understanding of same. I'd 
consider him abolutely untrustworthy were he to tell us that they 
already had a solution. ZEUS didn't have, until one or two years ago. 
What seems to be Your problem?

|>I'm tempted to go pull back up your speculations =Doctor= Hallam-Baker,
|>to compare with the material I've presented thus far. ;^)

So why don't You just do that? Let me summarise: You apparently didn't 
understand the above paragraphs, You didn't understand Phills position
on the data processing at all (as to the financial matters, well, given
the examples of FNAL, CERN and DESY, a well-equipped lab with a certain
infrastructure, for computing, maintainance and otherwise, will cost 
something along the lines of 1/3 G$, with about 1/4th of that going into 
the direct operating of the machine) and You consistently misrepresented 
the amount of data expected. I have yet to come to a position, where I
respect Your statements more than Phill's.

|> /                 \     |     /  Of all sciences, there is none where  \
|>(  Stephen D. Tice  ) -- S -- (   first appearances are more deceitful   )
|> \                 /     |     \  than in politics.     - David Hume -  /
                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                                   So, You've got the right quote. Why don't
You just apply it to a) Yourself, b) the stuff I've just cut out. Throwing
quoted material into the discussion without apparent rhyme or reason makes
the particpants only feel mutlued, with predictable results.

Satan help me, lest I become abusive!

       Till Poser         Internet: poser@vxdsyc.desy.de
-F35- ZEUS DESY/Freiburg  Bitnet:   POSER@DESYVAX
bldg.1b-235, Notkestr.85  Hepnet:   VXDESY::POSER (13313::Poser)
   D-2000 Hamburg 52      Tel.: -49-40-8998-2004
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