Thank you for the reply.
So it sounds like the content within this article is not accurate, regarding user space threads and "These threads follow co-operative multitasking where-in a thread releases CPU on its own wish ie the scheduler cannot preempt the thread." Is my understanding correct?:
User threads Vs Kernel Threads
Threads can exist in user space as well as in kernel space.
A user space threads are created, controlled and destroyed using user space thread libraries. These threads are not known to kernel and hence kernel is nowhere involved in their processing. These threads follow co-operative multitasking where-in a thread releases CPU on its own wish ie the scheduler cannot preempt the thread. Th advantages of user space threads is that the switching between two threads does not involve much overhead and is generally very fast while on the negative side since these threads follow co-operative multitasking so if one thread gets block the whole process gets blocked.
A kernel space thread is created, controlled and destroyed by the kernel. For every thread that exists in user space there is a corresponding kernel thread. Since these threads are managed by kernel so they follow preemptive multitasking where-in the scheduler can preempt a thread in execution with a higher priority thread which is ready for execution. The major advantage of kernel threads is that even if one of the thread gets blocked the whole process is not blocked as kernel threads follow preemptive scheduling while on the negative side the context switch is not very fast as compared to user space threads.