Introduction to virtual machines (7)-OSI Virtual Machine Model

OSI Virtual Machine Model

"Virtual" means that although an object or device does not exist at a certain time, people can see it.

The word "Virtual Machine" is easy for many people to think about. Pop Media and News Broadcasts often use the word "virtual" when reporting new developments in computer simulation and computer games. In any situation, the use of "virtual" means that although an object or device does not exist at a certain time, people can see it. This usage of virtual machines is a reasonable assumption about the development of virtual machines. The creation and continuous development of extended virtual machines are the Dual Logic Improvement of the computer operating system in terms of capability and flexibility.

To understand the extended Virtual Machine Model, the key is to understand how modern computers are designed and how operating systems control them. A modern operating system consists of a series of instruction sets, which are combined to form service routines. Service routines and data are combined to become applications submitted to the computer. Combining commands into a service routine is like Combining simple actions by office staff to complete a more complex task (such as the office supply directory. For example, a clerk has only one limited instruction set that can be executed in the memory. These commands are limited to computing, record the results of the previous operation, and archive some information for future use. Using these commands alone does not have much value, but these commands can be combined into a sequence, allowing clerks to complete an office supply directory. This command sequence may be: Number of output record paper, record result, number of pencils, record result, number of output paper clips, record result, archive and save. This sequence can be used repeatedly to complete directory service requests. The use of commands such as the number of records is assumed that the office clerk has the instinct to identify the records paper and the exact count. For humans, identifying objects and counting are the natural functions of the clerk's brain and eyes. For simulated office clerks or computers, these functions need to be designed at the hardware level and reflected in the circuit system. When investigating the actions of office clerks in detail, it is obvious that some basic functions frequently used in the circuit system need to be implemented, rather than Combining simple commands. Office clerks must walk around the office in person, check objects, and use Notepad and pencil to record counting results. These functions are implemented as a series of repeated hardware actions and software commands. For example, the "record the last result" command will include the following operations: accessing a storage part (such as a disk storage), locating the space for storing data, obtain the data to be recorded in the local register, transfer the data, and write the data to the hard disk. At the circuit layer, there is a basic layer where all commands are derived from this layer.

The underlying commands are the Zero-One code that is submitted to the computer. They generate mobile data, configure the system or create conditions for the next action. This level can be regarded as the machine command level, and the operating system-level commands are derived from this level. Now, we all know that any instruction set is a simple combination of the next instruction set. The tasks to be completed by office clerks are actually a series of sub-tasks. These subtasks are combined to form a more complex operation sequence. When the "directory" command is issued to the office clerk, the observer can only understand the meaning of the word "directory" and the overall action of the office clerk. The underlying instruction subset is invisible to the observer. Each successive command layer, including machine circuit, machine code, operating system commands, and application code, hides the underlying commands from its next layer. Combining commands and building more complex operations is the key to understanding how to expand virtual machines.

The ultimate goal of Virtual Machine scaling is to build capabilities and simulation devices that do not exist in the computer. For example, most computers have a hard disk to store data and program commands. This hard disk may actually be on another computer or may consist of multiple devices on the computer. In this case, the virtual machine extension method is to write a sequence of commands, making users feel that there is only one hard drive on the computer. The simulated single drive has the same storage capacity as the hardware drives on all computers. On the computer, you can only see one hardware drive. You only need to use a combination of commands to store and obtain data on a large hardware drive. User-called command access is a child routine composed of the underlying commands. The underlying commands in the subroutine process such details as what information is stored on which disk.