Showing posts from March, 2015

Internals of Read and write operation in hadoop

In previous post  we learned about HDFS building blocks namenode, datanode , secondry namenode. In this post, I will be discussing read and write operation in HDFS . It is the HDFS client (a library that exports the HDFS filesystem interface) which co…

Python Input and Output

In order to accept user input via console and display result, python has in built methods like raw_input() and print(). We have seen uses of print() in earlier post, reading input via console will be focus of this post. Along with console reading, Pyt…

Oracle JDK installation in Ubuntu

Since Oracle’s Sun Java JDK packages has been removed from the Ubuntu partner repositories. Now we are left with two option:  either go with Open JDK or Oracle JDK. The fundamental difference between open jdk and oracle jdk is OpenJDK is a reference m…

NameNode, DataNode and Secondary NameNode

In previous post we learned that, NameNode(NN) and DataNode(DN) are main building block of HDFS(Hadoop Distributed File system).In this post we will see NN and DN in details,interaction among and architecture in HDFS. NameNode and DataNode : HDFS c…

Git Commands Recap : Tagging, Branching, Merging

Git Tagging : git tag <tag_version> git tag command is used to tag a given commit with version/tag name. Below command open default editor and tag current commit with tag v1.0. (which can be validated with "git log" command ) ➜…

Arrays interview questions

Write code snippet for displaying matrix elements in a spiral order Create a matrix with alternating rectangles of O and X Find minimum element in rotated and sorted array Find an element in 2D sorted array or search target element in 2D sorted a…

Big data evolution - Relational model to Hadoop ecosystem

Database technologies has went through dramatic transformation from pre-stage flat-file system  to relational database system(RDBMS). Undoubtedly, RDBMS has been de facto database system for longer period of time for both small and large scale industr…

Git Commands Recap : Add, rm, commit, diff

Git Add : git add <file_name1>,<file_name2> If a file need to be committed to repo, it needs to be brought first to staging area(staging index) from working directory. The "git add" command is used to move files from working…

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