Virtual Machine Simulator was an Operating System lecture project.This simulator holds up to 5 operating systems in itself and each operating system has its own weight. (this weights are used as priorities to schedule all operating systems in virtual machine).Each operating system may have up to 10 processes each with its own arrival time and burst time. Also each operating system has its own scheduling algorithm to schedule the processes (First Come First Served, Shortest Job First, Round Robin), This simulator may run for a random based simulation or user defined values. It draws ganth charts associated to operating systems and the virtual machine itself. This was the first main part of this project, second part of this project includes memory paging algorithms for processes, each operating system has its own memory paging algorithm (Least Recently Used, Optimal).