In multiprocessing several processors require to communicate with one another. So synchronisation is needed between them. The correctness and performance of parallel execution relies on significant synchronisation amongst simultaneous computations in many processes. The synchronisation problem can arise due to sharing of writable data objects amongst processes. Synchronisation involves implementing order of operations in an algorithm by finding dependencies in writable data. Shared object access in MIMD architecture needs dynamic management at run time that is much more complex as compared to SIMD architecture. Low-level synchronization primitives are applied straight forward in hardware. Other resources such as Bus, memory unit and CPU too require synchronisation in Parallel computers.