This lab manual is dedicated to the students who are studying Parallel Processing systems and will help them to undersand concepts of data parallel programmning and shared memory multiprocessors programming. In the first chapter we describe Parallaxis, a structured programming language for data-parallel programming with a lot of examples included.. Parallaxis simulation environment allows studying of data parallel fundamentals on single processor systems and development of parallel programs which can later be executed on real SIMD systems. At the end of the chapter a list of assignments is given. The second chapter gives a theoretical background about interprocessor communication and communication in MIMD systems. The third chapter contains a description of BACI concurrency simulator which is used as a simulation environment for communication and synchronization in multiprocessor systems using binary and counting semaphores and Hoare monitors.At the end of the chapter a list of student assignments is given.