Difference between User Threads and Kernel Threads

User-level threads are managed by user-level software and are faster than kernel-level threads, as they do not require kernel mode privileges. These threads are created and managed by thread libraries like POSIX threads and Mach C-Threads. They are highly portable and useful in systems lacking native multithreading support. However, user-level threads face limitations in multiprocessing and blocking operations.

For more details, check out the full article here.