Information technology virtualization
The usual goal of virtualization is to centralize administrative tasks while improving scalability and overall hardware-resource utilization. In other words, the major reason for virtualization is that it is cost effective. Para-virtualization[ edit ] Paravirtualization is another virtualization technique that presents a software interface to virtual machines that is similar, but not completely the same as that of underlying hardware. Most servers use only a small fraction of their overall processing capabilities. Such instances, called containers,  partitions, virtual environments VEs or jails FreeBSD jail or chroot jail , may look like real computers from the point of view of programs running in them. However, with a well-developed and maintained system, virtualization can still save money and increase efficiency. For example, the host operating system could run Windows, while the guest OS runs Linux. One is that it doesn't take advantage of modern server computers' processing power. Rather than interacting with a host computer directly via a keyboard, mouse, and monitor, the user interacts with the host computer using another desktop computer or a mobile device by means of a network connection, such as a LAN , Wireless LAN or even the Internet.
Virtualized memory Also evolving rapidly in the s was the concept of virtual memory, arguably just as important as virtual machines. One is that it doesn't take advantage of modern server computers' processing power.
Each self-contained VM is completely independent. Any requests by the VM for a location on its physical disk are transparently translated into an operation on the corresponding file.
Information technology virtualization
Video game console emulation[ edit ] Main article: Video game console emulator A video game console emulator is a program that allows a personal computer or video game console to emulate a different video game console's behavior. Virtual desktop infrastructure VDI After virtual machines and virtual memory, and the availability of these capabilities in low-cost microprocessors and PCs, the next advance was the virtualization of the desktop and thus the availability of applications, both single-user and collaborative. Sounding familiar yet? Again, we must return to the timesharing model introduced above, but in this case we are emulating the desktop of a PC on a server and essentially remoting the graphics and other user-interface elements over a network connection, to an appropriate software client and often to an inexpensive and easy-to-manage-and-secure thin-client device. Thus, the entire stack of snapshots is virtually a single coherent disk; in that sense, creating snapshots works similarly to the incremental backup technique. Software and services are installed to make channels of which are securely separate from each other and can be assigned to particular devices. Main article: Snapshot computer storage A snapshot is a state of a virtual machine, and generally its storage devices, at an exact point in time. As a consequence of these innovations, still hard at work today, hardware otherwise designed to run a single program or operating system could be shared among users even with simultaneous multiple operating systems and massive memory requirements beyond the real capacity provisioned. Based on the strategy of virtualizing much of IT into cloud-based services, virtualization is best thought of today as an alternative operating model with economic advantages that obviate the need for traditional implementations. As hardware became cheaper, more powerful, more cost-effective, and quasi-standardized, the focus shifted to applications running in essentially-standardized and virtualized environments, from PCs to browsers. This makes it possible to run multiple operating systems and applications on the same server at the same time, transforming the IT landscape and the way technology is utilized. Main article: Failover Similar to the migration mechanism described above, failover allows the VM to continue operations if the host fails. Run multiple operating systems on one physical machine.
Whereas computers and computing used to be at the core of IT, we have shifted to a focus on information and making that information available anytime and anywhere.
There are four main operating systems companies that control most of the market today.
By using specially designed software, an administrator can convert one physical server into multiple virtual machines. Find out in the next section. While it has often been described as such, virtualization itself is not a paradigm shift. Examples are the operating system, storage, disk drives, etc. Run multiple operating systems on one physical machine. Apple follows right behind Microsoft and Google for operating systems in desktops and smartphones. Operating Systems[ edit ] An operating system is a system that maintains a computer's software and hardware and allows the computer to do the simple task for its programs. For example, installing Microsoft Windows into a VM guest requires its licensing requirements to be satisfied. Reasons for Virtualization[ edit ] One of the main reasons for virtualization is to cut costs on the amount of servers that would be on a network.
Based on the strategy of virtualizing much of IT into cloud-based services, virtualization is best thought of today as an alternative operating model with economic advantages that obviate the need for traditional implementations.
Types of Virtualization Server Virtualization Server virtualization enables multiple operating systems to run on a single physical server as highly efficient virtual machines. Find out in the next section.
Types of hardware virtualization
Any requests by the VM for a location on its physical disk are transparently translated into an operation on the corresponding file. It is the simulated part of a computing device that cannot be touched. It also enables centralized control over what applications the user is allowed to have access to on the workstation. Hardware-assisted virtualization is a way of improving overall efficiency of virtualization. Much more so than the hardware which they are replacing. In theory, you could create enough virtual servers to to use all of a machine's processing power, though in practice that's not always the best idea. Each self-contained VM is completely independent. However, programs running inside a container can only see the container's contents and devices assigned to the container. Apple follows right behind Microsoft and Google for operating systems in desktops and smartphones. Hardware Virtualization[ edit ] This type of virtualization creates a simulation of a real computer with a working OS operating system. Main article: Failover Similar to the migration mechanism described above, failover allows the VM to continue operations if the host fails. Each virtual server acts like a unique physical device, capable of running its own operating system OS. Once such a translation layer is present, however, it is possible to intercept the operations and send them to different files, depending on various criteria. Software executed on these virtual machines is separated from the underlying hardware resources.
It also has the capability of moving from one machine to another which saves costs as well. Some have central processing units CPUs with multiple processors that give these servers the ability to run complex tasks with ease.
Security[ edit ] The fact that virtualization allows for full control of its environment means that it can be made much more secure. Virtual machines frequently use virtual disks for their storage; in a very simple example, a gigabyte hard disk drive is simulated with a gigabyte flat file.
In theory, you could create enough virtual servers to to use all of a machine's processing power, though in practice that's not always the best idea.
Any software that needed the hardware that wasn't simulated would need to be modified to be usable in the simulated environment.
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