Regardless of of the fact that a thread must execute in process, the process and its associated threads are different notion. Processes are used to group resources together and threads are the articles scheduled for execution on the CPU.
A thread is a single sequence stream surrounded by a process. Because threads have some of the aspects of processes, they are at times called lightweight processes. In a process, threads permit multiple executions of streams. In many value, threads are popular way to get better application through parallelism. The CPU switches quickly back and forth among the threads giving false impression that the threads are running in parallel. As a traditional process i.e., process with one thread, a thread can be in any of a number of states (Running, Blocked, Ready or terminated). Every thread has its individual stack. Since thread will generally call different procedures and therefore a different execution history. This is why thread necessitates its own stack. An operating system that has thread facility, the necessary unit of CPU utilization is a thread. A thread has or consists of a register set, program counter (PC), and a stack space. Threads are not independent of one other similar to processes as a result threads shares with additional threads their code section, data section, OS resources also recognized as task, such as open files and signals.