Read the paper "PARACACHE: Educational Simulator for Cache and Virtual Memory". It compares three existed educational simulators (Camera [1], ECS Cache Simulator [2], and Cache-Sim [3]) with the proposed PARACACHE simulator. Follow the reference [1]-[3] to find out current status of these three simulators and write a report to describe them. Run these three simulators with a sample block reference string with at least 20 blocks if you can, or write a report to describe the issues that encountered during your simulation