There is nothing sacred about electrons being called negative charge and protons positive charge.Itâs just a convention. You, can very well call electrons as positive charge and protons as negative charge!
Single Node or Psuedo-Distributed Cluster is the one in which all the essential daemons (like NameNode, DataNode, JobTracker and TaskTracker) run on the same machine. The default replication factor for a single node cluster is 1. A single node cluster is basically used to simulate a full cluster like environment and to test hadoop applications and unlike the Stand-alone mode, HDFS is accessible in this.
Oracle Clusterware is the software which enables the nodes to communicate with each other, allowing them to form the cluster of nodes which behaves as a single logical server.t provides the basic clustering services at the operating system level that enable Oracle software to run in clustering mode. In earlier versions of Oracle (version 9i and earlier), RAC required a vendor supplied clusterware like Sun Cluster or Veritas Cluster Server with the exception of Linux and Windows.