Virtual Machine (I)-What is a virtual machine?

Due to work requirements, the leader requires that the virtual machine be installed on the same machine to split the application and database into two logical machines. So I began to learn about virtual machines.
First, you should understand-what is a virtual machine?

The concept of virtual machines is relatively broad. Generally, people are exposed to the concept of virtual machines, such as hardware simulation software such as VMWare, as well as hardware and compilation such as JVM. Program Software. 2. a virtual machine is an abstract computer. Like an actual computer, it has an Instruction Set and uses different storage areas. It executes commands and manages data, memory, and registers. This virtual machine provides a common interface for compiling programs on any platform. To compile a program, you only need to target the virtual machine to generate a virtual machine that can understand it. Code The interpreter then converts the virtual machine code to the machine code of a specific system for execution.
Virtual Machine Software Several PCs can be simulated on one computer. Each pc can run a separate operating system without interfering with each other. A single computer can run several operating systems simultaneously, you can also connect these operating systems into a network.

A part of the hard disk and memory is taken out on a computer to virtualize several machines. Each machine can run a separate operating system without interfering with each other, these "new" machines have their own separate CMOS, hard disks, and operating systems. You can partition, format, and install systems and application software like normal machines, you can also associate these operating systems into a network. After the virtual system crashes, you can delete it directly without affecting the local system. Similarly, the local system crash does not affect the virtual system. You can re-install it next time and then add it to the previous virtual system. It is also the only virtual computer software that can run on Windows and Linux host platforms. Virtual Machine software can use several operating systems on the same computer without re-boot, which is both convenient and secure. Virtual machines play a major role in learning technology.

Virtual Machine)
Virtual machines (VMS) are a system that allows multiple operating systems to run on a single physical server in parallel, providing more effective underlying hardware usage. In a virtual machine, the central processor chip divides a storage area from other parts of the system, and the operating system and applications run in the "protection mode" environment. If a program is frozen in a virtual machine, the operation of the program running outside the virtual machine and the normal operation of the operating system will not be affected.
Virtual machines have four architectures. The first type is "one-to-one ing", which is most typical of IBM virtual machines. The second type is composed of machine virtual instruction ing, which is the most typical Java virtual machine. The UNIX Virtual Machine Model and the OSI virtual machine model can directly map some commands, while others can directly call the operating system functions.
In a real computer system, a device driver in an operating system controls hardware resources and converts system commands into specific device control languages. If the ownership of the device is independent, the driver is formed, so that multiple operating systems cannot run concurrently on a single computer. Virtual machines include technologies to overcome this limitation. The virtualization process introduces the resource redirection interaction function of the lower-layer device without affecting the upper-layer application layer. Through virtual machines, you can run multiple operating systems concurrently on a single computer.

The Microsoft Virtual Server 2005 is based on the OSI Virtual Machine Structure and mainly consists of the following:
the host operating system, such as Windows Server 2003, controls the host system.
the virtual machine operating system, such as Virtual Server 2005, contains the vmm Virtual Layer that controls the virtual machine, providing the software structure for hardware simulation.
each virtual machine is composed of a set of virtual devices, each of which has the corresponding virtual hardware.
the customer's operating system and applications can run on virtual machines without the support of any interactive network adapters. A virtual server is only a software simulation device in the physical Ethernet.