Hadoop on Mac with IntelliJ IDEA-11 Hadoop version derivation

The recently read material always mentions Hadoop 0.20, 0.23, and so on, causing individuals to be quite surprised by the version of Hadoop: 1.2.1 is still behind the 0.23, you are kidding me. Curiosity, a search, found a document, the following are from the document, here to make a backup.

Excerpted from Dylan. Advanced applications for Hadoop Big Data Solutions-Hadoop 2.0 (1).

1. First Generation Hadoop:hadoop 1.0

• Contains three large versions, 0.20.x, 0.21.x, 0.22.x, and CDH3, respectively
• The 0.20.x finally evolved to 1.0.x, becoming a stable version.
• 0.21.x and 0.22.x Add new major features such as Namenode ha

2. Second Generation Hadoop:hadoop 2.0

• Includes Apache Hadoop 0.23.x, 2.x, and CDH4, both with HDFs Federation and Yarn Systems
• 2.x adds two major features of Namenode ha and wire-compatibility

3, Apache software release method: According to the new features extended version
4, independent generation of Hadoop version of the major features

Append
Support File Append function
Raid
Build Drfs to reduce the number of data blocks by introducing checksums, with the assurance of reliable data
Symlink
Support for HDFs file links
Security
Security authentication and authorization mechanism
MRv1
Mrv2/yarn
NameNode HA
HDFS Federation

Hadoop on Mac with IntelliJ IDEA-11 Hadoop version derivation