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.
Star topology networks generally have a hub in the center of the network that connects all of the devices together using cabling. When bits hit a networking device, be they hubs, switches, or routers, the devices will strengthen the signal and then send it on its way. A hub is simple a multiport repeater. There is usually no software to load, and no configuration required (i.e. network administrators donât have to tell the device what to do).