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.
A node is a point in the circuit at which connections among components meet. In the circuit of Fig. 4C there are two nodes, one at the top of the circuit and one at the bottom. In the circuit of Fig. 4B, there are three nodes, two between the voltage source and the two resistors (top and bottom) and one.