What is exactly meaning of disconnected and connected approach in ADO.NET

Question

I am learning ADO.Net. I read this line:-

DataReader is \"connected\" approach and dataset is \"disconnected\" approach

From this

Answer 1

Connected Architecture : For Every request , Hit the Database , Fetch the DATA and bring Back. you can perform only Read Operation.Connection should be always OPEN.Uses Data Reader

Dis Connected Architecture : Fetch the Entire Data at once and now perform whatever operation you want to perform. Isert / Update / Delete. No need for the connection to be always OPEN.Uses Data Set , Data Adapter