2. History The prototypical illustration of full virtualization is in the control program of IBM's CP/CMS operating system – first demonstrated with IBM's CP-40 research system in 1967, then distributed via open source in CP/CMS in 1967-1972, and re-implemented in IBM's VM family from 1972 to the present. Each CP/CMS user was provided a simulated, stand-alone computer. Each such virtual machine had the complete capabilities of the underlying machine, and (for its user) the virtual machine was indistinguishable from a private system. This simulation was comprehensive, and was based on the Principles of Operation manual for the hardware. It thus included such elements as instruction set, main memory, interrupts, exceptions, and device access. The result was a single machine that could be multiplexed among many users.
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6. Software Virtualization runs the virtualized operating system on top of a software virtualization platform running on an existing operating system.
7. Hardware Virtualization runs the virtualized operating system on top of a software platform running directly on top of the hardware without an existing operating system. The engine used to run hardware virtualization referred to as a hypervisor.
43. Its hypervisor is called ESXOracle (Oracle VM), Novell (Xen), Red Hat (Xen), IBM, Sun (xVM), Virtual Iron, and others also all offer their own hypervisors
44. Software Appliances A software appliance is a software application combined with just enough operating system (JeOS) for it to run optimally on industry standard hardware (typically a server) or in a virtual machine. JeOS is the abbreviation (pronounced "juice") for the concept of Just Enough Operating System as it applies to a software appliance. JeOS is not a generic, one-size-fits-all operating system. Rather, it refers to a customized operating system that precisely fits the needs of a particular application. The application's OS requirements can be determined manually, or with an analytical tool. Therefore, JeOS includes only the pieces of an operating system (often Linux) required to support a particular application and any other third-party components contained in the appliance. This makes the appliance smaller, and possibly more secure than an application running under a full general purpose OS.
45. FIREWALL Virtual Appliance CRM Virtual Appliance Linux Linux What is a Virtual Appliance Firewall SW Pre-built, pre-configured and ready-to-run software application packaged with the OS inside a Virtual Machine. Or packaged inside multiple Virtual Machines Linux Apache mySQL Tomcat Linux
46. Virtual Appliances Virtual appliances are virtual machine templates, sometimes in the Open Virtualization Format (OVF), that contain preconfigured operating systems and applications. Since VMs are self-contained and transportable, they can be delivered in a preconfigured state as virtual appliances. VAPs are most often designed to run on Linux operating systems because of the licensing cost. Few vendors have created VAPs based on Microsoft technologies because they have to become Windows resellers to do so. Some considerations that need addressable when we choose a VAP: Has the OS been hardened? Is the appliance upgradeable? Scalability Microsoft v/s Linux Licensing Custom OS?
