Technology classification of virtualization technology

Mainstream virtual technology, the mainstream x86 virtual machine technology mainly has such categories: The virtual hardware model establishes an abstract virtualization platform between computer, storage and network hardware, so that all hardware is unified into a virtualization layer. Today, the typical products of such virtual machines are Vmware's Workstation, GSX Server, ESX Server and Microsoft's Virtual PC, Virtual Server and Parallels Workstation.

Virtual Hardware Mode Features: Virtualizes the Intel x86 platform, allowing multiple operating systems and applications to run simultaneously. Hardware-level virtualization is provided through the use of a virtualization layer, where the virtual machine provides a virtual set of Intel x86-compatible hardware for the operating system image running on the virtual machine. This virtual hardware virtualizes all the equipment that a real server has: motherboard chips, CPU, memory, SCSI and IDE disk devices, various interfaces, displays, and other input and output devices. And, each virtual machine can be individually encapsulated into a single file, allowing for flexible migration of virtual machines. In the ever-growing list of virtualization technologies, Xen is one of the most notable in recent times. xen was developed as a research project at the University of Cambridge, and it has gained a lot of traction in the open-source community. xen is a paravirtualizing VMM (Virtual Machine Monitor), which is a virtual machine that can be used to monitor the virtual machine's performance. Monitor), which means that the operating system has to be selectively modified in order to invoke the system hypervisor, but the applications running on the operating system do not need to be modified.Xen is a special kind of virtual hardware VM that has most of the characteristics of a virtual hardware VM, with the major difference that Xen requires modifications to the operating system kernel.

Today, Xen only supports Linux virtual machines implemented on top of Linux systems. However, a new version will support Intel's hardware virtualization technology, Intel-VT, a key technology that could be used to address Xen's difficulties in virtualizing Windows systems.

VMware is still the leader in virtualization technology, and it still has a clear advantage over XenSource in terms of product maturity. But many industry insiders believe that Xen will grow stronger as a result of open source. Today, open source giants Red Hat and Novell have begun to integrate the technology into their Red Hat Enterprise Linux 5 systems, as well as into Novell and SuSE Linux Enterprise Server 10 systems.