A process can have many threads

so to perform a task faster we break the process in threads.

Creation of new process requires new resources and Address space whereas the thread can be created in the same address space of the process which not only saves space and resources but are also easy to create and delete and many threads can exhists in a process.

Process is some job or task which is running in background.

while a thread is a single line of execution in a programs so many threads can be there in a program.

Threads share the address space of the process that created it; processes have their own address.

Threads have direct access to the data segment of its process; processes have their own copy of the data segment of the parent process.


Threads can directly communicate with other threads of its process; processes must use inter-process communication to communicate with sibling processes.

Threads have almost no overhead; processes have considerable overhead.

New threads are easily created; new processes require duplication of the parent process.

Threads can exercise considerable control over threads of the same process; processes can only exercise control over child processes.

Changes to the main thread (cancellation priority change etc.) may affect the behavior of the other threads of the process changes to the parent process does not affect child processes.

Both have an id set of registers state priority and scheduling policy.

Both have attributes that describe the entity to the OS.

Both have an information block.

Both share resources with the parent process.

Both function as independent entities from the parent process.

The creator can exercise some control over the thread or process.

Both can change their attributes.

Both can create new resources.

Neither can access the resources of another process.