And it is true that ATLAS can float. However, you would have to wrap it in Saran wrap (a lot of Saran wrap!) first…

The trigger for the LHC is a fascinating and, to some extent, scary topic. In my previous experiment at LEP, we accumulated about 4 million hadronic Z decays (among other events). That was essentially all of the produced Z bosons. We only missed a couple thousand. And we even have a pretty good idea why we didn’t trigger on those events. In other words, our acceptance was about 100%. At the LHC, the number of potentially interesting events produced will simply be too high: on the order of 10 to 100 thousand events per second. We only have the capability to record data at 100-300 Hz. Thus we have to throw away the least interesting events, while ensuring that we record the really exciting ones like the Higgs events (should they exist). A daunting task!

For the lay person like myself this compartive relation of information dropped down to “scale” is important. As it puts into perspective the “reality” around us.

The value of the Qubit, and the lesson we may learn on how computerization may now meet new ways to decipher LIGO INformation?

Many physical quantities span vast ranges of magnitude. Figures 0.1 and 0.2 use images to indicate the range of lengths and times that are of importance in physics.

So I find it difficult to image the relation in the complexity of the “rain drop” too a string? Yet, LHC serves it’s purpose from the bottom up?:)

# A gigabyte is about a billion bytes (actually 2^30 of them).

* 1 gigabyte: the human genome, or a pickup truck full of books.

* 20 gigabytes: a good collection of the works of Beethoven.

* 100 gigabytes: a library floor of academic journals.

# A terabyte is about a trillion bytes (actually 2^40 of them).

* 2 terabytes: an academic research library.

* 6 terabytes: all academic journals printed in 2002.

* 10 terabytes: the print collections of the U.S. Library of Congress.

* 40 terabytes: all books printed in 2002.

* 50 terabytes: all mass market periodicals printed in 2002.

* 60 terabytes: all audio CDs released in 2002.

* 80 terabytes: capacity of all floppy discs produced in 2002.

* 140 terabytes: all newspapers printed in 2002.

* 170 terabytes: the searchable portion of the World-Wide Web in 2002.

* 250 terabytes: capacity of all zip drives produced in 2002.

# A petabyte is about 10^15 bytes (actually 2^50 of them).

* 1.5 petabytes: all office documents generated in 2002.

* 2 petabytes: all U.S academic research libraries.

* 6 petabytes: all cinema release films in 2002.

* 20 petabytes: all X-ray photographs taken in 2002.

* 90 petabytes: the “Deep Web” in 2002.

* 130 petabytes: capacity of all audio tapes produced in 2002.

* 400 petabytes: all photographs taken in 2002.

* 440 petabytes: all emails sent in 2002.

# An exabyte is about 10^18 bytes (actually 2^60 of them).

* 1.3 exabytes: capacity of all videotapes produced in 2002.

* 2 exabytes: capacity of all hard disks produced in 2002.

* 5 exabytes: all the words ever spoken by human beings.

* 6 exabytes: information in the genomes of all the people in the world.

You may think you don’t need to look at my webpage now, but you’re wrong! You have to look at it to see how much information it takes to completely describe the quantum state of a typical raindrop.

The pdf by Paris Sphicas at
http://www-conf.slac.stanford.edu/ssi/2006/lec_notes/Sphicas072606.pdf
is very interesting, and I am sure that you heard much more at the actual talks and discussion, so I am looking forward to your post on triggering.

Will you also discuss cuts, another important stage of filtering what will actually be analyzed at LHC?

Tony Smith
http://www.valdostamuseum.org/hamsmith/

Beyond Einstein, and from Seti it was learnt? Why not use “other” computers?

You take the chance on blogging, to see the benefits later on?:) A new student , a lay person, who now can’t get enough. More then, just the “pizza guy” and or the “toppings” for sure. And we have this developing theory from what has already been produced in experimental research?

How appropriate.

http://pancake.uchicago.edu/%7Ecarroll/images/cms1.jpg

Sean Carroll:

As a theorist (and one who grew up in astronomy departments), one of the most fascinating concepts in high-energy experiments is that of a trigger. Each detector will witness approximately one billion collisions per second, which is a lot. You might imagine that you’re faced with two problems: simply recording all the data from each event, and then sifting through them for the interesting bits. You’re right, but it’s much worse than you think. That’s because each event isn’t just a few bytes if data; it’s of order one megabyte per event. There’s simply no way you could record all of the data.

I believe you’re a few orders of magnitude off on the event size. If I recall correctly, ATLAS events are about one megabyte each, corresponding to order of 100 MB of data being stored per second. This gives me 100*10^7 MB = 1000 terabytes a year. (Experimentalists usually call a year 10^7 seconds, rather than 3.15*10^7, because we’ll be lucky to collect data that fraction of the time.) That’s a pretty big strain on available computing power as it is—keep in mind that we don’t just need to store all that data, but make it accessible to all the collaboration members who want to analyze parts of it.

And what ever you do.. don’t lick the beam pipe

I’m not sure this is such a good idea. Word is a bit of a bloated format. How many bytes would 10,000 Encyclopedia Britannica’s be in ASCII??

Also, in response to spatulated (#28), according to Wikipedia 1 Library of Congress = 67,000 Britannica’s. I guess the data volume recorded at the front-end of CMS corresponds to about 9 Library of Congress’s per minute.

No it makes perfect sense to make this reference. A terabyte, even for the smartest people, is hard to conceptualize. It is like when someone says “American is 1trillion dollars in debt” that number is so huge its worthless and wasted on the brain.

But, people have seen the encyclopedia; they know its huge, and 10,000 is a number we can almost visualize (though a secondary size comparison might help — how many libraries of congress would that fill?)

Also, it attaches a sense of emotion to it. I have never encoded data, but I have written a paper. I have spent hours and hours writing 20page papers. And that is next to nothing compared to one letter in the encyclopedia. Now the whole thing? 10000 times? A SECOND?!?!?

Emotive, interesting, comprehendible.

Oh and, its 2006

Oh, and you spelled “encypledia” wrong. Its 2006 man, where is your spell check?