2012年3月26日 星期一

Apache Hadoop

Apache Hadoop






  • Hadoop Common: 在0.20及以前的版本中,包含HDFSMapReduce和其他项目公共内容,从0.21开始HDFS和MapReduce被分离为独立的子项目,其余内容为Hadoop Common
  • HDFS: Hadoop 分佈式文件系統 (Distributed File System) - HDFS (Hadoop Distributed File System)
  • MapReduce并行计算框架,0.20前使用 org.apache.hadoop.mapred 旧接口,0.20版本开始引入org.apache.hadoop.mapreduce的新API







[编辑]Hadoop與Sun Grid Engine

昇陽電腦的Sun Grid Engine可以用来调度Hadoop Job。[3][4]


威斯康辛大學麥迪遜分校的Condor計算機集群軟件也可以用作Hadoop Job的排程。[5]



  1. ^ Yahoo! Launches World's Largest Hadoop Production Application (Hadoop and Distributed Computing at Yahoo!)
  2. ^ PoweredBy
  3. ^ Creating Hadoop pe under SGESun Microsystems. 2008-01-16.
  4. ^ HDFS-Aware Scheduling With Grid EngineSun Microsystems. 2009-09-10.
  5. ^ Condor integrated with Hadoop's Map Reduce威斯康辛大學麥迪遜分校. 2010-04-15.


2011年11月30日 星期三


「網路星期一」(Cyber Monday)是一行銷專有名詞,指感恩節促銷「黑色星期五」過後的第一個星期一。在零售業者發現線上營業額會在這一天顯著增加之後,多通路零售業者協會Shop.org於2005年首次提出這個用語。2006年,Shop.org推出CyberMonday.com入口網站,讓消費者能一網打盡各樣網路星期一的折扣優惠。現在網路星期一已是每年最盛大的線上購物日之一。

2011年11月16日 星期三

Five Tips For Getting iPhone Reviews


Five Tips For Getting iPhone Reviews

Guest author Jim Bernard is the General Manager of MarketWatch.com and an iPhone marketing enthusiast. He can be reached at bernard.jim at gmail.com
Even though Mobile Orchard does not review apps, we get a surprising number of product pitches. Some are quite brilliant, others almost embarrassingly bad. This got us thinking: what makes a successful pitch-email?
To find out, we asked the experts at 148AppsAppCraverappstoreapps.com, and apptism to share the tips and tricks of creating a really excellent pitch. There was significant consensus among these sites, summarized here in five easy suggestions:
1. Provide complete information. Regardless of how great your program is, reviewers will not go to the app store and search around to find it. Every email, website, video should include basic information such as the app name, your contact information, company name, and link to the app store page. This may seem like a basic tip, but reviewers report that it is common to get inquires that are lacking basic information. “If I have to ask for something, I probably wonʼt and just ignore the app,” says Jeff Scott at 148Apps.
2. Start with a great description. Lead your inquiry letter with a precise description of what your application does, what segment it belongs in (games, productivity, etc.) and why it is unique or interesting. “Keep it simple and to the point,” said Rob Libbey at apptism. “Show the facts and differentiators of your app in short concise bullet points or sentences.” Stay away from anything not related to your app — reviewers do not respond well to calls for sympathy or other gimmicks.
3. Include promotion code. Reviewers want a promotion code with your request for coverage. “Immediately provide a promo code for publishers to try the app hands-on,” suggests Libbey. Make it easy for them to write about your application by giving them a chance to try it right away. This may require a more selective set of places where you go for reviews, but better to get a few mentions than none.
4. Make a great video. A short video that shows your application in action is perhaps one of your best selling tools. It allows reviewers to get a sense of the graphics, sound and interaction in just a few seconds. Videos should be no longer than two minutes–if you hook the reviewer youʼll do it right away. Also, pay attention to production quality, especially sound, image clarity, etc. “Itʼs unfortunate, but I donʼt have time to download and test every app that comes out,” said Barbara Holbrook, Editor in Chief, at AppCraver. “A video takes just seconds to watch and can be the difference in whether an app gets a longer look.”
5. Put your best app forward. “Most important of all” says Holbrook, “make sure your app is polished and superior to the competition before submitting it to the app store or to publishers.” Many aspiring developers submit apps that are by their own admissions incomplete. Publishers report getting submissions that say, “I created this app in 5 minutes. Itʼs not very good but your feedback would be appreciated.” If you canʼt take time to polish your application, why should a reviewer take time to provide feedback and encouragement?
Holbrook summed up the chase between developers and review sites this way: “Crafting your email to an editor is like creating a profile on a dating site. You want to do everything possible to get that editor to ‘wink’ back at you. Profiles with photos get more winks, but profiles with videos that show personality get even more.”
Thanks to Jim Bernard for contributing this article. Have an article, or an idea for an article, that might interest our readers? Contact us!

2011年11月15日 星期二


OpenGL(全寫Open Graphics Library)是個定義了一個跨程式語言、跨平台編程介面(Application programming interface)的規格,它用於生成二維三維圖像。
這個介面由近三百五十個不同的函式呼叫組成,用來從簡單的圖元繪製複雜的三維景象。而另一種編程介面系統是僅用於Microsoft Windows上的Direct3D。OpenGL常用於CAD虛擬實境、科學視覺化程式和電子遊戲開發
根據OpenGL官方網站,2002年6月的ARB投票成員包括3DlabsApple ComputerATI TechnologiesDell ComputerEvans & SutherlandHewlett-PackardIBMIntelMatroxNVIDIASGISun MicrosystemsMicrosoft曾是創立成員之一,但已於2003年3月結束)。


當獨立廠商建立一種新技術時,OpenGL標準允許它們透過「擴充功能」的方法提供所擴充功能的功能。然後一個擴充功能就分成兩部分釋出:包含擴充功能函式原型的表頭檔和作為廠商的裝置驅動。每個廠商有一個用於命名它們的新函式和常量的字母縮寫。例如,NVIDIA的縮寫(「NV」)用於定義它們的專有函式「glCombinerParameterfvNV()」和它們的常量「GL_NORMAL_MAP_NV」。如果多於一個廠商同意實作相同的擴充功能功能,那麼就用縮寫「EXT」。進一步,架構評審委員會可能「祝福」這個擴充功能,那麼這就被稱為一個「標準擴充功能」,使用縮寫「ARB」。第一個ARB擴充功能是GL_ARB_multitexture。根據官方擴充功能提升路徑,多紋理不再是可選實作的ARB擴充功能,它已經是OpenGL 1.4以後的核心API的一部分。
特別是,OpenGL Performer庫——由SGI開發並可以在IRIXLinuxMicrosoft Windows的一些版本上使用,構建於OpenGL,可以建立即時視覺化模擬程式。


為了加強它的多語言和多平台特性,已經用很多語言開發了OpenGL的各種繫結和移植。最值得注意的是,Java3D庫已經可以利用OpenGL(另一個選擇可能是DirectX)作為它的硬體加速了。OpenGL官方網頁 [1] 列出了用於JavaFortran 90PerlPikePythonAdaVisual Basic的多個繫結。




OpenGL進化自(而且風格很相似)SGI的早期3D介面IRIS GL
IRIS GL的一個限制是它只能存取底層硬體提供的特性。如果圖形硬體不支援例如紋理對映這樣的功能,那麼應用程式就不能使用它。OpenGL透過在軟體上對硬體不支援的特性提供支援的方法克服了這個問題,允許應用程式在相對低配置的系統上使用高階的圖形特性。Fahrenheit項目是Microsoft和SGI之間的聯合行動,為了統一OpenGL和Direct3D介面的目的。它一開始提出了一些把規則帶給互動3D電腦圖形API世界的承諾,但因為SGI的財政限制,這個項目後來被放棄了。
2002年微軟的DirectX 9提出了全新的Shader繪圖功能以及高階著色語言 (HLSL),OpenGL霸主地位開始被瓦解。這使得3DLabs了解到必須開發全新的OpenGL 2.0版本,但僅加入支援GLSL的功能。2006年Khronos接手OpenGL,立刻著手發展Longs Peak與Mount Evans。2008年推出OpenGL 3,但評價普遍不高。
2010年3月10日, OpenGL同時推出了3.3和4.0版本,同年7月26日又釋出了4.1版本。2011年8月8日釋出4.2版本。