Spark was introduced by Apache Software Foundation for speeding up the Hadoop computational computing software process.
As against a common belief, Spark is not a modified version of Hadoopand is not, really, dependent on Hadoop because it has its own cluster management. Hadoop is just one of the ways to implement Spark.
Spark uses Hadoop in two ways – one is storage and second is processing. Since Spark has its own cluster management computation, it uses Hadoop for storage purpose only.