Changes between Version 15 and Version 16 of Virtualization

Timestamp:

Jan 10, 2007 6:34:19 PM (17 years ago)

Author:

jose

Comment:

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Virtualization

@@ -1 +1 @@
 = Virtual machines = 
 
-When we describe !VirtualBox as a "virtualization" product, we refer to the particular kind of virtualization that allows an unmodified operating system with all of its installed software to run in a special environment on top of your existing operating system. This environment, called a "virtual machine", is created by the virtualization software by intercepting access to certain hardware components and certain features. The physical computer is then usually called the "host", while the virtual machine is often called a "guest". Most of the guest code runs unmodified, directly on the host computer, and the guest operating system "thinks" it's running on real machine.
+When we describe !VirtualBox as a "virtualization" product, we refer to "full virtualization", that is, the particular kind of virtualization that allows an ''unmodified'' operating system with all of its installed software to run in a special environment, on top of your existing operating system. This environment, called a "virtual machine", is created by the virtualization software by intercepting access to certain hardware components and certain features. The physical computer is then usually called the "host", while the virtual machine is often called a "guest". Most of the guest code runs unmodified, directly on the host computer, and the guest operating system "thinks" it's running on real machine.
 
 This approach, often called "native virtualization", is different from mere emulation. With that approach, as performed by programs such as [http://bochs.sourceforge.net/ BOCHS], guest code is not allowed to run directly on the host. Instead, every single machine instruction is translated ("emulated"). While emulators theoretically allow running code written for one type of hardware on completely different hardware (say, running 64-bit code on 32-bit hardware), they are typically quite slow. Virtualizers such as !VirtualBox, on the other hand, can achieve near-native performance for the guest code, but can only run guest code that was written for the same target hardware (such as 32-bit Linux on a 32-bit Windows host).