Lecture

Memory Virtualization: Address Space Abstraction and Management

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In course

CS-202: Computer systems

This course will teach operating systems and networks in an integrated fashion,emphasising the fundamental concepts and techniques that make their interaction possible/practical. Core lectures will be coupled with C programming lectures and assignments for ...

Description

This lecture introduces the concept of memory virtualization, focusing on how the operating system creates the illusion of infinite memory for applications. It begins by discussing the role of the operating system as both an illusionist and a referee, managing resources and ensuring process isolation. The lecture emphasizes the address space abstraction, detailing the logical view of a process's memory, which consists of four segments: stack, heap, data, and text. The instructor explains the management of the stack and heap as dynamic data structures, and makes a case for virtual memory, highlighting its implementation through segmentation. The lecture also covers the memory management unit (MMU) as a crucial component that provides a level of indirection, allowing the CPU to interact with virtual rather than physical memory. Additionally, the principle of indirection is presented as a fundamental design approach in systems, with examples of batching and caching as other important principles in operating system design.

Instructors (2)

Edouard Bugnion

Edouard Bugnion joined EPFL in 2012, where his focus is on datacenter systems. His areas of interest include operating systems, datacenter infrastructure (systems and networking), and computer architecture. Before joining EPFL, Edouard spent 18 years in the US, where he studied at Stanford and co-founded two startups: VMware and Nuova Systems (acquired by Cisco). At VMware from 1998 until 2005, he played many roles including CTO. At Nuova/Cisco from 2005 until 2011, he helped build the core engineering team and became the VP/CTO of Ciscos Server, Access, and Virtualization Technology Group, a group that brought to market Ciscos Unified Computing System (UCS) platform for virtualized datacenters. Prof. Bugnion is a Fellow of the ACM. Together with his colleagues, he received the ACM Software System Award for VMware 1.0 in 2009. His paper Disco: Running Commodity Operating Systems on Scalable Multiprocessors" received a Best Paper Award at SOSP '97 and was entered into the ACM SIGOPS Hall of Fame Award in 2008. At EPFL, he received the OSDI 2014 Best Paper Award for his work on the IX dataplane operating system

Jean-Cédric Chappelier

Jean-Cédric Chappelier is currently senior researcher and lecturer in Computational Linguistics at the Ecole Polytechnique Fédérale de Lausanne (Switzerland). He holds an Ms.Sci. and a Ph.D. in Computer Science from the Ecole Nationale Supérieure des Télécommunications de Paris (France).

Official source

Ontological neighbourhood

Computer engineering

High-performance computing: Real-time computing

Computer architecture: Topics in computer architecture

Related concepts (32)

Memory paging

In computer operating systems, memory paging (or swapping on some Unix-like systems) is a memory management scheme by which a computer stores and retrieves data from secondary storage for use in main memory. In this scheme, the operating system retrieves data from secondary storage in same-size blocks called pages. Paging is an important part of virtual memory implementations in modern operating systems, using secondary storage to let programs exceed the size of available physical memory.

Hardware virtualization

Hardware virtualization is the virtualization of computers as complete hardware platforms, certain logical abstractions of their componentry, or only the functionality required to run various operating systems. Virtualization hides the physical characteristics of a computing platform from the users, presenting instead an abstract computing platform. At its origins, the software that controlled virtualization was called a "control program", but the terms "hypervisor" or "virtual machine monitor" became preferred over time.

Application virtualization

Application virtualization is a software technology that encapsulates computer programs from the underlying operating system on which they are executed. A fully virtualized application is not installed in the traditional sense, although it is still executed as if it were. The application behaves at runtime like it is directly interfacing with the original operating system and all the resources managed by it, but can be isolated or sandboxed to varying degrees.

CPU cache

A CPU cache is a hardware cache used by the central processing unit (CPU) of a computer to reduce the average cost (time or energy) to access data from the main memory. A cache is a smaller, faster memory, located closer to a processor core, which stores copies of the data from frequently used main memory locations. Most CPUs have a hierarchy of multiple cache levels (L1, L2, often L3, and rarely even L4), with different instruction-specific and data-specific caches at level 1.

Virtual machine

In computing, a virtual machine (VM) is the virtualization or emulation of a computer system. Virtual machines are based on computer architectures and provide the functionality of a physical computer. Their implementations may involve specialized hardware, software, or a combination of the two. Virtual machines differ and are organized by their function, shown here: System virtual machines (also called full virtualization VMs) provide a substitute for a real machine. They provide the functionality needed to execute entire operating systems.

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Virtual Memory

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Memory Virtualization: Page-Based Management Techniques

Discusses page-based virtual memory, focusing on its mechanisms, benefits, and address translation techniques.

Virtual Memory: Principles and Mechanisms

Covers the principles and mechanisms of virtual memory in computer systems, focusing on isolation, efficiency, and the role of the Memory Management Unit.

Virtual Memory: Memory Organization & Virtualization

Explores memory organization, virtualization, dynamic memory allocation, stack, heap, and memory virtualization techniques like base register and segmentation.

Virtualization Principles: Mechanisms and Applications