What is a virtual machine
Virtual machine refers to a complete computer system with the functionality of a full hardware system simulated by software and running in a completely isolated environment.
What can be done in a physical computer can be done in a virtual machine. When creating a virtual machine in a computer, some of the hard disk and memory capacity of the physical machine needs to be used as the hard disk and memory capacity of the virtual machine. Each virtual machine has a separate CMOS, hard disk, and operating system, and the virtual machine can be operated as if it were a physical machine.
Virtual machines can emulate other kinds of operating systems, which require simulation of the underlying hardware instructions, so they are much slower than virtual systems in terms of application runtime.
Popular virtual machine software includes VMware (VMWareACE), VirtualBox and VirtualPC, all of which can virtualize multiple computers on a Windows system.
Main uses of virtual machines:
1. Demonstration environments, you can install a variety of demonstration environments, which makes it easy to do a variety of examples.
2, to ensure the fast operation of the host, to reduce unnecessary garbage installers, the occasional use of the program, or test the program to run on the virtual machine.
3, to avoid reinstalling each time, the bank and other common tools, infrequent use, and the requirement of better confidentiality, run separately in an environment below.
What is a virtual machine
A virtual machine (VM) is one that allows you to run other operating systems within your current operating system, and the virtual operating system will run like another program on your computer.
Windows 10 or other Linux operating systems are often ideal for testing other operating systems, and can also use a virtual machine to run software on the operating system it was designed for, such as the ability to run Windows programs on a Mac with a virtual machine.
Details:
A virtual machine is a program that acts as a virtual computer. A virtual machine runs on the current operating system (host operating system) and provides virtual hardware to the user operating system. The user operating system can run in a window on the host operating system, just like any other program on the computer. It can be said that a virtual machine is a real physical computer from the point of view of the user operating system.
The virtual machine’s emulation engine (called a hypervisor) handles the virtual hardware, including the CPU, memory, hard disk drives, network interfaces, and other devices. The virtual hardware devices provided by the hypervisor are mapped to the actual hardware on the physical machine, manifested as the virtual hard disk of the virtual machine stored in a file on the hard disk drive.
Reference for the above: Baidu Encyclopedia-Virtual Machine
What is a virtual machine
Virtual machine: a virtual machine (VM) is an operating system that shares the physical resources of a server. It is a Guest on the host hardware, hence the name Guest VM.
Virtual machines consist of several layers. The layer that supports virtualization is the hypervisor. hypervisor is a software that virtualizes servers.
Virtualization technology has been with the operating system since its inception. Because of the limitations of hardware, people have wanted to use software to emulate hardware from the beginning, and this is the core idea behind virtual machines.
A virtual machine is an operating system that is virtualized under the local operating system, and the operations on the hardware in the virtual machine are converted to correspond to changes in the physical machine. You can think of a virtual machine as a real computer, because it provides the functionality equivalent to a physical computer for the user.
A virtual machine packages virtual hardware, a kernel (i.e., an operating system), and user space in a new virtual machine that can run on top of a physical device using a hypervisor. Virtual machines rely on a hypervisor, which is usually installed on top of “bare metal” system hardware, which leads to the hypervisor being considered an operating system in some ways. Once the hypervisor is installed, virtual machine instances can be allocated from the system’s available compute resources, with each virtual machine receiving a unique operating system and load (application). In short, a virtual machine needs to first virtualize a physical environment, then build a complete operating system, then build a layer of runtime, and then supply applications to run.
What is a virtual machine
What is a virtual machine?
What is a virtual machine? –A comprehensive analysis of virtual machine technology
A virtual machine, also known as a virtual computer, is a technology that creates multiple virtual computer environments on a physical computer. Virtual machines can run separate operating systems and applications and provide the same functionality as a separate physical computer.
The history of virtual machine technology in computing can be traced back to the 1960s, when multi-user operating systems required time-division multiplexing to accomplish support for multiple users, but due to the performance limitations of time-division multiplexing, the operating system performance was very low. The emergence of virtual machine technology breaks the limitations of time-division multiplexing technology, realizing the distribution of multiple users’ operating systems and applications on a single physical computer, which greatly improves the utilization and performance of computers.
Virtual machines are implemented through virtualization technology. Specifically, virtual machine software abstracts the hardware resources of a physical computer (such as the CPU, memory, and hard disk) and builds a virtual computer environment on top of it. Each virtual machine has its own operating system and application programs, which communicate with the physical computer hardware resources through the virtual machine software and are independent of each other and do not interfere with each other.
Virtual machine technology is widely used in today’s cloud computing and big data environment. In cloud computing, virtual machines can be dynamically created, started, and destroyed on individual compute nodes through services provided by cloud server providers. In big data environments, virtual machines can effectively isolate individual applications, providing better security and flexibility.
The development of virtual machine technology also faces a number of challenges. Performance and interoperability of virtual machine software are two major issues at present. The performance problem of VM software is mainly due to the fact that VM software requires additional computational resources to maintain communication between VMs and interaction between operating systems. The interoperability problem, on the other hand, manifests itself in incompatibility issues between different operating systems and applications, limiting the application scenarios of virtual machine technology.
In conclusion, virtual machine technology is an important computer technology with a wide range of applications, but there are also some challenges. With the continuous development of virtual machine technology, it is believed that it will become more and more mature and perfect, and make greater contributions to the progress of computer technology.