Evaluating Virtual Memory Algorithms in the UR-OS Simulator

The UR-OS operating system simulator is an academic tool designed to support the teaching and learning of concepts in the area of Operating Systems. This simulator incorporates a complex structure that emulates active elements of a computer system (processor, main memory, swap memory, interrupts) and of an operating system (process management, memory addressing, etc.). In its current version, UR-OS allows modeling virtual memory management algorithms, like First-in-First-out (FIFO), Least Recently Used (LRU), among others. The main characteristic of this simulator is that it is a very simple tool to work with and modify, and it is freely available for academic activities and research. In this work, two new virtual memory algorithms are introduced: Second-chance Least-Frequently-Used (SCLFU) and Least Recently/Frequently Used (LRFU). These techniques were tested over three distinct scenarios: sequential, random, and patterned memory accesses. Results show that mainly in random scenarios, both LFU and LRFU reduce the page faults in the testing scenario, compared to the rest of the algorithms.