This document highlights the topics required by Project 2 – Research – Memory Management and Virtual Memory for Operating Systems, Class from 2014. This article presents a case study of Microsoft. Windows 7 64-bit professional operating system.2. Memory2.1 Description: Main memory is the central hub where all programs are executed. It consists of a wide array of bytes, each with its own address. The amount of main memory is a limiting factor in a computer system, the more memory we have, the more addressable space the operating system has, increasing the number of programs that can be executed and the amount of information ready to be executed . When the instructions are ready to execute, the scheduler sends them to the CPU. This process may require several transitions between memory and processor. The memory unit only recognizes a stream of memory addresses, it does not understand how they are generated or what their purposes are. 2.2 Physical Memory: Most current operating systems today support 64-bit addressing, which includes our case study, Windows 7 x64 Professional. . The hardware and software limitations of 32-bit chips, limited to a maximum of 2 GB user-addressable or 4 GB of RAM access, hastened this transition. A 64-bit chip address space is increased to 2^64 bytes of RAM and can significantly increase system performance and the way programs can be written without having to consider the above constraints. - Windows 7 Professional 64-bit has a limit of 192 GB in address space.2.3 Virtual Memory: Virtual memory is a memory management technique implemented using hardware and software. It maps the memory addresses used by a program, called virtual addresses...... middle of paper ......e is assigned an age value consisting of three bits which determines the age of a page, thereby helping the operating system decide which memory page can be removed from physical memory. The reference counter used in the aging algorithm and the way in which it is used ensures that pages referenced more recently, although less frequently referenced, will have a higher priority over pages more frequently referenced in the past: thus, when If a page needs to be replaced, the page with the lowest counter will be chosen.3. Conclusion: Windows 7 is the first widely adopted 64-bit operating system in the Microsoft family. It fixed many security issues and significantly improved the performance and some features of its predecessors. It has evolved into a stable and reliable operating system and holds the majority share installed on most personal computers worldwide..