这里有一封信，令人激动，虽然是一封格式信，但是让我感到温暖，同在一片蓝天下，贡献一点点力量，帮助了别人，也在帮助自己
World Community Grid，IBM的一个Grid计算项目。我下面对Grid计算稍作解释，网格(grid)计算的基本想法是把尽量多的计算机通过网络连接，通过一些算法把整体的项目分解为一份一份的计算项目，让每台参与网格计算的计算机承担一份或者多份计算，最终由网格计算的主机汇总这些单独的计算得到最终的结果。理论上，参与计算的计算机越多，网格计算的整体计算能力越强大。
举个例子，比如说有A, B两台计算机参与了网格计算，题目(VB语法)是：
a=1:b=2:c=3
x=a+b:y=a+c:z=x+y
第一行算作参数传递，第二行算作计算过程，假设参数传递运行时间可以忽略，计算过程每一步时间消耗为1。
那么，作为一个单独的计算机，整个计算过程的时间是3
而如果我们考虑如下过程，
让A计算机计算x=a+b，B计算机计算y=a+c，然后把x,y传递给A或者B计算z=x+y，那么整个计算过程的时间是2。可以看到实际上网格计算是一种并行计算。
实际当中，参数通过网络传递一定有延迟，这个延迟会降低整体的计算性能。考虑大型计算的规模，实际网络传递的延迟可以忽略不计。并行计算带来了另外一个问题，如果改一下题目：
a=1:b=2:c=3:d=4
x=a+b:y=x+c:z=y+d
不管是不是用网格计算还是单机计算，计算时间都是3，也就是说并不是所有题目都能通过并行计算提高性能。
实际上，网格计算的优势体现在大规模的并行计算，比如在寻找素数的工作中，每个计算机可以独立承担验证一个数是否是素数的工作，甚至可以验证其中一段，比如验证3128312831是不是素数，一台计算机可能只需要计算这个数是否可以被2~1000整除。
在并行计算的项目里，网格计算是一种被看好的取代大型计算机的计算方式，因为理论上，大型计算机的计算能力的提高受到物理极限的局限，而且大型计算机成本巨大，而网格计算能力的提高取决于参与网格计算的计算机的多少，每台计算机都是普通的pc，提到计算能力所需要的成本远低于大型计算机。
IBM这个项目和现在世界上大部分网格计算项目都采取了一种相同的方式来扩展参与的计算机。他们推出一种客户端软件，客户端可以从服务器下载数据，并且向服务器传递计算结果。这个软件抢占所有空闲的CPU资源，或者集成在屏保程序中，利用计算机的空闲时间进行计算。对于每个人来说，安装客户端，That's all!。
如果觉得自己CPU够好，不会因为连续的100%的占用率而烧掉，就可以尝试一下这些网格计算项目。说不定我们微薄的力量汇聚成的计算能力能帮助人类找到克服癌症的方法。Try it!
Dear XX,
World Community Grid is pleased to announce that the Help Defeat Cancer (HDC) project is finished. The last work units have been sent out and when the final results are returned, the project will come to an end. This project, which launched on July 20, 2006, will have run for just over 9 months by the time the last results are returned. During this time 88,000 members will have donated 2,900 years of computer time on 138,000 different computers. This is a significant contribution to cancer research.
But the end of this project is really only a beginning. Based on the results, the researchers who are working on this project have a very aggressive plan to make Tissue Microarray technology an integral part of early cancer detection. World Community Grid's team will keep in close touch with the research team and will post updates on the website in the Research pages (http://www.worldcommunitygrid.org/projects_showcase/viewResearch.do ). The researchers will also continue to update their HDC website (http://pleiad.umdnj.edu/IBM/ ) with exciting updates about this project and the inroads it is making on cancer research.
On behalf of the research staff at the University of Medicine and Dentistry of New Jersey, World Community Grid's team wish to express our thanks to you for contributing your PC power to this project. With your contribution, this project was completed in a fraction of the time it would otherwise have taken.
We also want to inform you that World Community Grid has started work on a new cancer project to discover ways to accelerate the crystallization process used in studying cancer protein structure using X-ray Crystallography, which will help researchers identify proteins involved in cancers and lead to new drug therapies and cures. We plan to launch this new cancer project in the May/June 2007 time frame. You will receive more information on this project prior to the official launch date.
We still need your help with other ongoing projects! World Community Grid continues to run the FightAIDS@Home, Genome Comparison, Help Cure Muscular Dystrophy and Human Proteome Folding - Phase II projects. These critical research projects need your computer time as well.
IMPORTANT: If you have elected to participate only in the Help Defeat Cancer project (which has now been completed), you must take some action to prevent your World Community Grid agent from sitting idle on your PC until the next cancer project launches. Please sign in to World Community Grid, and from the "My Grid" page, select the "My Projects" link from the menu on the left. From the "My Projects" page, select one or more of the other projects in which you choose to participate. If no action is taken within the next 3 weeks, we will set your default to Participate in All Projects. You will then be automatically enrolled to participate in the next cancer research project when it is launched in May or June.
Again, thank you for your contribution to the highly successful completion of the Help Defeat Cancer project!
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Personal Statistics
- Registered: April 01, 2005
- Run Time: 1 day
- Points: 181
- Results: 1
- Registered: April 01, 2005
- Run Time: 1 day
- Points: 181
- Results: 1
If you no longer wish to receive the World Community Grid newsletter, click here: http://www.worldcommunitygrid.org/unsubscribe.do?memberId=74819&auth=61c20d888052bfa8fffc864ede10cb92
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