Difference between HBase and Hadoop/HDFS

This is kind of naive question but I am new to NoSQL paradigm and don't know much about it. So if somebody can help me clearly understand difference between the HBase and Hadoop or if give some pointers which might help me understand the difference...

Will Big Data and Apache Spark continue to be hyped in 2018?

How to use Alibaba Cloud OSS as a storage system in Hadoop？

Hadoop and MySQL

How is Hadoop compared to MySQL, are they competitors or can they supplement each other? Can I use Hadoop and Hive to process large data and serve it into a MySQL database that my application access?

Do I need a dedicated graphic card to run all IDE (Android Studio, NetBeans, Hadoop, etc.)?

Does Apache Thrift work to structure the datanodes in HDFS, MapReduce, or both?

It was my understanding that dfs-datastores were used to structure datanodes in HDFS. Where does Apache Thrift fit into Hadoop?

Hadoop giving error on avro tools concat

I'm trying to concatenate multiple avro files in an HDFS directory using avro tools. I'm following the approach as this question. However, I'm getting the following error: Exception in thread "main" java.io.FileNotFoundException: /user/myuser/output/...