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Virtualization techniques are commonly associated with operating systems, but they can significantly improve application deployment and management, as well.
Application virtualization is a deployment model that allows programs to run on various devices without conventional installation. Instead of depending on a device's operating system, a virtualized application is bundled with all the components it needs, and it executes on a target device in ways that simulate a fully installed application.
Application virtualization brings benefits to both administrators and users, including streamlined installations, minimized conflicts between applications, reduced migration costs, and improved support for mobile devices and remote work.
You can use XenApp to deploy applications to a full range of commonly used platforms, including Windows, Mac OS X, iOS, Android and HTML5-enabled browsers.
Virtual applications avoid certain device-specific complications, such as needing a specific version of an operating system. But virtual apps must still be able to address some integration issues, such as printing. XenApp includes a universal print-anywhere printing service, which lets users print from applications without requiring device-specific drivers.
XenApp supports broad classes of applications that include 16-, 32- and 64-bit applications, as well as apps designed for Windows Server 2008 R2, Windows XP, Windows 7 and Windows 8.
End users can take advantage of a self-service portal to find and run enterprise applications with XenApp, and application administrators have granular access controls at their disposal to limit applications to designated users.
Citrix XenApp is optimized for visualizations and multimedia redirection. There is also support for USB. Smartphone and tablet users benefit from optimizations designed to make Windows applications easier to use on touchscreen devices.
Users may experience improved application performance, too. For example, having both applications and data in the data center can improve performance over local installation. Deploying application virtualization infrastructure to multiple redundant data centers can improve availability. It also eliminates or reduces the time it takes to provision new hardware in a disaster recovery situation.
VMware's application virtualization tool, ThinApp, operates in user mode, so it presents no risk of disrupting the host operating system or breaking an existing installed system. It creates self-contained virtualized applications.
ThinApp uses an agentless deployment mechanism so there is no software to install on the host device, again avoiding risks associated with installing code on the host, such as altering the file system or making changes to the Windows registry. Another advantage of this approach is that the virtualized application is not subject to interference from other applications installed on the host device. The risk from malware is limited to damage that can be done in user mode.
As is the case with XenApp, applications virtualized with ThinApp do not require device drivers, which commonly cause management issues. ThinApp addresses security concerns, in part, by the fact that malware running in a virtualized application is subject to user-mode constraints.
ThinApp integrates with Active Directory (AD), and administrators can configure virtualized applications to use AD authorizations and group policies.
Applications can run from USB devices or optical disks and require only a small (approximately 400 KB) runtime. Other runtime optimizations include block-based streaming decompression and the ability to load DLLs and ActiveX controls over the network. ThinApp streams applications to allow faster load times -- only the code and data the app needs to start up are loaded at the beginning, then the other parts of the app travel over the network as users need them.
ThinApp supports 16-, 32- and 64-bit applications designed to run on a long list of Microsoft operating systems, including NT, 2000, XP, XPE, 2003, Vista, Windows 7 and Server 2008.
Microsoft's application virtualization platform offers many of the same features that the other major options listed here do, such as streaming applications on demand and integration with AD. As with those alternatives, administration is streamlined. For example, it's unnecessary to uninstall applications deployed with App-V.
App-V has features you might expect from a Microsoft system, such as administrative templates and a Windows PowerShell administration interface. In addition, administrators can optimize multiple virtualization tools. For example, App-V supports a shared content repository with VDI and remote desktop services. For organizations supporting users with poor or infrequent connectivity, administrators can deploy MSI-based application packages for remote users with intermittent connectivity.
Application virtualization is an effective tool for reducing application administration overhead while decoupling applications from specific user devices. System administrators and end users alike can benefit greatly from virtualized applications.
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