What is Virtual: Definition and 565 Discussions

In computing, a virtual machine (VM) is the virtualization/emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized hardware, software, or a combination.
Virtual machines differ and are organized by their function, shown here:

System virtual machines (also termed full virtualization VMs) provide a substitute for a real machine. They provide functionality needed to execute entire operating systems. A hypervisor uses native execution to share and manage hardware, allowing for multiple environments which are isolated from one another, yet exist on the same physical machine. Modern hypervisors use hardware-assisted virtualization, virtualization-specific hardware, primarily from the host CPUs.
Process virtual machines are designed to execute computer programs in a platform-independent environment.Some virtual machine emulators, such as QEMU and video game console emulators, are designed to also emulate (or "virtually imitate") different system architectures thus allowing execution of software applications and operating systems written for another CPU or architecture. Operating-system-level virtualization allows the resources of a computer to be partitioned via the kernel. The terms are not universally interchangeable.

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  1. P

    Virtual antiparticle pairs at event horizon

    One of my friend had asked me one question which I did not really have a good answer for. His question was: Why does the antiparticle counterpart of the virtual antiparticle pairs (those that appear due to uncertainty between time and energy) at the event horizon fall into the black hole...
  2. turbo

    Virtual particles and cosmological expansion

    I re-read parts of "Genius" by James Gleick earlier today after visiting a web-site that discussed steady-state cosmology. Apparently, Feinman felt that the creation and obliteration of virtual particles (diagramed by equivalent waves moving BOTH forward and backward in time) supported the idea...
  3. Ivan Seeking

    3D ads to put virtual beers on bars

    http://www.newscientist.com/news/news.jsp?id=ns99994807
  4. O

    Real photon - virtual particle collisons

    Seems to me that in deep space real photons collide often with virtual particles. Is that a reasonable theory? If so, what are the (approximate or ball-park) statistics? What does happen? Does the putative virtual particle involved in a collision with a real photon become real? What are the...
  5. arivero

    Exchange rate of virtual particles?

    Suppose two particles bound by electromagnetic interaction, kind of hidrogen atom. How do you calculate the number of virtual photons exchanged by unit of time? Has this frequency of exchange some meaning in usual textbooks?
  6. E

    Exploring Virtual Particles: Understanding the Concept

    Hi everyone! Time has come for my first thread in this nice forum: I wonder if someone could explain the concept of virtual photons (and virtual particles in general)? Have I understood it right that they are just a mathematical construction and are not in any way "real"? I have a lack of...
  7. W

    Virtual Displacement: Analyzing Langrange Equations

    hey, all i'm now studiynd analytical mechanics and the subject is Langrange equations. What i can't grasp is the meaning of virtual displacement term. The formal definition says that: it's a small displacement of particle with agreement to constraints in such a way that no time passes...
  8. M

    A Virtual Scanning Electron Microscope

    A Virtual Scanning Electron Microscope, the link is provided to me (and anyone who reads that Journal) by the People at the Journal Science, The AAAS... Click http://www.vcbio.sci.kun.nl/eng/fesem/"
  9. P

    Virtual Particles and Theoretical Physics: Exploring Time Travel and Wormholes

    my name is cory mccall and i live in spf mo. i am a junior in high school who is extremely interested in the fields of theoretical nuclear particle and astrophysics. for the first year I am going to submit a project to the science fair. over the course of about a month I am goin to be throwing...
  10. P

    Exploring Theoretical Physics and Virtual Particles: A Junior's Perspective

    my name is cory mccall and i live in spf mo. i am a junior in high school who is extremely interested in the fields of theoretical nuclear particle and astrophysics. for the first year I am going to submit a project to the science fair. over the course of about a month I am goin to be throwing...
  11. S

    Virtual particles and sorce theory

    Ok so if you can't see it then how do you really know anything about the effect or behavior on the unmeasured side? Isn't this dependent on the particular interpretation used, such as the Copenhagen Interpretation for instance? I mean what really is the "collapse of the wave function"...
  12. Tyger

    What's real and what's virtual?

    The issue arises whether virtual particles can be considered to be "real" in the same sense that photons of light can be. So exactly when is a photon real and when is it virtual, and do virtual photons have as much right to be thought of as existing as "real" ones? A real photon (free field...
  13. W

    Virtual particles and entanglement

    Are virtual particles entangled when they appear? If so then when one of the pair falls into a black hole and other flies off, do they remain entangled? If so, does this mean that by observing black hole radiation we can in principle 'see inside'?
  14. Saint

    Creating a Virtual CD on Your Hard Drive: Easy Autorun and Duplication

    Let say I have an installation CD of Microsoft office, which can autorun. How can I create a virtual CD on my hardisk , copy the whole contents of the CD onto my HDD. When I double click the virtual CD, it can autorun; and, I can also burn it onto a blank CD, duplicate it. What software...
  15. R

    Escape Velocity of virtual particles

    I know that the escape velocity for virtual particles being emitted from black holes is c2+ (in the black hole entropy formula, there is an escape velocity of c3). I also know that Hawking radiation and for that matter*(I don't mean matter in physics terms), any radiation being emitted from a...
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