2/27/2013
IT109
Inst. Bomani

VMware, Inc. is an American software company, founded in 1998, providing cloud and virtualization software and services on desktop platforms such as Microsoft Windows, Linux, and Mac OS X. Its founders were Diane Greene, Mendel Rosenblum, Scott Devine, Edward Wang and Edouard Bugnion. By the use of virtualization, VMware hides the physical computing platform by showing another abstract computing platform to the users. VMware developed a range of products, most notable of which are their hypervisors (virtual machine manager).
A virtual machine (VM) is a simulation of a machine that is usually different from the target or host workstation using a Virtual Player; which provides the means of running the virtual environment. Virtual machines emulate the computer architecture and functions of a real world computer. Virtual machines are separated into two major classifications, based on their use and degree of correspondence to any real machine: * A system virtual machine provides a complete system platform which supports the execution of a complete operating system. These usually emulate an existing architecture, and are built with either the purpose of providing a platform to run programs where the real hardware is not available for use (for example, executing software on otherwise obsolete platforms), or of having multiple instances of virtual machines lead to more efficient use of computing resources, both in terms of energy consumption and cost effectiveness (known as hardware virtualization, the key to a cloud computing environment), or both. * A process virtual machine (also, language virtual machine) is designed to run a single program, which means that it supports a single process. Such virtual machines are usually closely suited to one or more programming languages and built with the purpose of providing program portability and flexibility (amongst other things). An essential characteristic of a virtual machine is that the software running inside is limited to the resources and abstractions provided by the virtual machine—it cannot break out of its virtual environment.
The operating systems, that are able to run VMware, are Microsoft Windows, Linux, and Mac OS X. VMware software virtualizes the hardware for a video adapter, a network adapter, and hard disk adapters. The host provides pass-through drivers for guest USB, serial, and parallel devices. In this way, VMware virtual machines become highly portable between computers, because every host looks nearly identical to the guest or virtual environment.
There are disadvantages to using virtual machines are: * a virtual machine is less efficient than a real machine when it accesses the hardware indirectly * when multiple VMs are concurrently running on the same physical host, each VM may exhibit unstable performance (Speed of Execution, and not results), which highly depends on the workload imposed on the system by other VMs, unless proper techniques are used for temporal isolation among virtual machines.
Sun Microsystems developed their own virtual run-time environment called Java virtual machine (JVM) is a virtual machine that can execute Java instructions (bytecode); the code execution component of the Java platform. The most widely used JVM is “Hotspot”, and is written in C++ programming language. The VMware virtual environment accommodates several programming languages such as C#, Visual Basic .NET, J#, and C++/CLI. Although the JVM was primarily aimed at running compiled Java programs, many other languages can now run on top of it. VMware software does not imitate an instruction set for different hardware not physically present. This boosts performance, but can also cause problems when moving virtual machine guests between hardware hosts using different instruction-sets.
In 2009, TechTarget Virtualization prepared the Decisions 2009 Purchasing Intentions Survey of 666 IT professionals that had deployed or were evaluating virtualization. Data was collected between June and September 2009. Survey results indicated survey respondents reported using VMware Inc. over other virtualization software by a wide margin: 72.4% identified some VMware edition as their primary virtualization platform. VMware and Microsoft continue to play heavily in IT managers' future plans as well. Among the respondents planning to evaluate an alternative virtualization platform, a quarter is looking to the latest version of VMware.

References: 1. "How does VMWare Work?". Extremetech.com. 2009-06-22. Retrieved 2009-07-01. 2. Tulloch, Mitch (February 2010) (PDF). Understanding Microsoft Virtualization R2 Solutions. Microsoft Press. pp. 23–29. Retrieved February 18, 2010. 3. Vizard, Mike. "Desktop Virtualization sans the Hypervisor". IT Business Edge. 4. International business machines corporation; patent issued for controlling java virtual machine component behavior on a per-classloader basis. (2013). Journal of Engineering, , 585. Retrieved from http://search.proquest.com/docview/1289090209?accountid=27655 5. "The Java Virtual Machine Specification." American Scientist 85.4 (1997): 389. Opposing Viewpoints In Context. Web. 1 Mar. 2013. 6. “VMware, Hyper-V virtualization leave others in the dust”, Alex Barrett, News Director; Published: 23 Sep 2009. http://searchservervirtualization.techtarget.com/news/1369150/VMware-Hyper-V-virtualization-leave-others-in-the-dust