virt 101 - Day One: Introduction

Welcome to my virtualization 101 series of blog posts. This will introduce x86 server virtualization at a high level, and dig deeper into specific concepts. I will be posting regular updates in this series, and feedback is welcome.

Here are some of the concepts and terms that will be considered:

• Server Virtualization vs. Cloud Computing vs. Emulation
• When was virtualization introduced?
• How does virtualization work?
• x86 CPU Architecture
• Binary Translation
• Paravirtualization
• Hardware Assisted Virtualization
• Virtualized Memory Management
• Extended Page Tables or Nested Page Tables
• Virtualized I/O and Devices
• Benefits and Challenges of Virtualization

How does server virtualization compare to cloud computing, or emulation?

Cloud computing can be defined as the use of new or existing computing hardware and virtualization technologies to form a shared infrastructure that enables web-based value added services. The cloud is based on the efficient use of infrastructure to offer utility like services to customers.

Virtualization is not the same as cloud computing. Cloud computing offers a service that may utilize virtualization technology.

Server vIrtualization can be defined as a computing layer that enables one or more operating systems to function independently and simultaneously on the same compatible physical hardware.

Emulation is when one system behaves like another [1]. For example, running an ARM emulator on an x86 hardware platform. Virtualization utilizes emulation to a limited extent.

When was virtualization introduced?

Virtualization is not new. It was first realized in the 1960s using the CP-40 operating system on IBM's mainframe systems [1][2].

• 1960s - IBM released hypervisors on CP-40 and CP-67 operating systems [2]
• 1999 - VMware introduced virtualization to the x86 platform with VMware Workstation 1.0 [3][4]
• 2001 - IBM launched a hypervisor for midrange UNIX systems [2]
• 2001 - VMware release ESX Server 1.0 [5]
• 2003 - Public release of Xen [6]
• 2004 - Microsoft releases Virtual Server 2005 [7]

Many more vendors and enhanced solutions have been released since.

The broader definition of virtualization is evolving and taking on new meanings in this world of software defined everything.

That's it for the introduction.

Be sure to follow me to receive updates when more posts in this series become available. If you like this article, please share it with others.

the virtualization 101 series:

• Day One: Introduction.
• Day Two: Virtualization and x86 CPU Architecture

Keep on virtualizing!

References

[1] “Emulation or Virtualization? - Computerworld.” [Online]. Available: http://www.computerworld.com/s/article/338993/Emulation_or_Virtualization_. [Accessed: 02-Mar-2012].
[2] “IBM and HP virtualization.” [Online]. Available: http://www.ibm.com/developerworks/aix/library/au-aixhpvirtualization/index.html. [Accessed: 03-Mar-2012].
[3] “Virtualization History, Virtual Machine, Server Consolidation.” [Online]. Available: http://www.vmware.com/virtualization/history.html. [Accessed: 03-Mar-2012].
[4] “A brief history of VMware - Virtualization Pro.” [Online]. Available: http://itknowledgeexchange.techtarget.com/virtualization-pro/a- brief-history-of-vmware-2/. [Accessed: 03-Mar-2012].
[5] “VMware Media Resource Center - Company Milestones.” [Online]. Available: http://vmware.com/company/mediaresource/milestones.html. [Accessed: 03-Mar-2012].
[6] “Stephen Spector: ‘Over 300 companies and developers have contributed to Xen just for last year.’”[Online]. Available: http://www.freecloudalliance.org/news/tionews-Stephen.Spector.Interview. [Accessed: 03-Mar-2012].
[7] L. E. Carvalho, “Understanding and comparing the Hyper-V architecture.” [Online]. Available: http://social.technet.microsoft.com/wiki/contents/articles/understanding-and-comparing-the-hyper-v-architecture.aspx.