"The method of simultaneous operation of the same computer by the site and remote user without interfering with one another"

Two application requirements for operating remote computers

In a production environment such as deployment, diagnostics, and maintenance, there are scenarios such as:

Scene One: The field has operator a through the local login operation machine A, remote has the operator B need some way to also operate machine a.

The most common solutions are:

① Both sides login QQ, operator a request Remote Assistance, operator B accept the request for remote operation;

② through the team viewer and other remote control software, like QQ, the two sides to establish a session after consultation, remote operation.

Strictly speaking, the remote control via QQ and TV is actually a kind of remote assistance, the need to solve is:
Operator B assists with the current task of operator A, or it is the collaboration of both parties to complete the same task.

Therefore, for the following scenario, QQ, TV and other Remote Assistance means powerless:

Scenario Two: operator a B needs to perform different tasks separately. For example, a to see a movie, B to do Excel table.

Because a B to machine a control will conflict, at the same point in time, either a busy, or B wait.

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For scenario two, there are currently two solutions: Remote Desktop and virtual machine.

One, Remote Desktop solutions

1. What is Remote Desktop

Remote Desktop is a feature that Microsoft has introduced to make it easier for users to operate remote computers.

Currently, the Windows operating system that can use Remote Desktop features includes:
Windows Server
Windows XP
Windows Server 2003
Windows Server 2008
Windows Vista
Windows 7
Windows 8
Windows Server 2012

For the network (intranet, public network can) any one open the "Allow users to connect remotely to this computer" option of the computer, with the remote computer account and password users, you can use the "Remote Desktop Connection" program to access the computer, install software on it, run programs, perform various tasks, Just as on the remote computer on the spot.
More importantly, Remote Desktop differs from the aforementioned Remote Assistance in that Remote Desktop leverages the time sharing feature of the Windows system.
The working principle of time-sharing operating system is:
The operating system divides the CPU time into several fragments, called < time slices >. The operating system uses < time slice rotation > to serve each end user in < time slice >. When a host establishes a Remote Desktop connection with multiple remote users on the network, all computers that use the Remote Desktop Connection program become the terminal for that host, and each terminal has one user in use. The user interactively makes a command request to the system, and when the CPU polls the user for a time, the operating system accepts the user's command and displays the result interactively on the terminal to the user, who then issues the next command based on the results of the feedback to the terminal. Because each user takes turns to use their own time slices, each user will not feel the presence of a different user.
The time-sharing system has the following characteristics:
Multiplexing: Multiple users are using a single computer at the same time.
Macro view is that many people use a CPU at the same time, micro is a lot of people take turns using CPU at different time.
Interactivity: The user further requests a new request based on the results of the system response (the user intervenes each step directly, which is different from the batch processing system).
Exclusivity: The user does not feel that the computer is serving others, just as the entire system is exclusive to him.
Timeliness: The system responds to requests from users in a timely manner.

Learn how Remote Desktop works, and see how Remote Desktop Services and terminals communicate.
The RDP protocol (Remote Desktop Protocol) is used by the terminal. The RDP protocol, a proprietary protocol developed by Microsoft, follows and implements the ITU 128 standard of the International Telecommunication Union and extends it. The latest versions of RDP are version 8.0 (in Windows 8 or Windows Server 2012).
In the RDP protocol, a remote user can run an RDP client to connect to the computer over the network as a graphical interface, as long as one computer is running the RDP server software.
Although the RDP protocol is a private protocol developed by Microsoft, there are RDP client programs on each platform of the Windows,linux,unix,mac OS x,ios,android, and Microsoft's RDP Server software is built into the Windows system, But now there are RDP Server software on Linux as well. As a result, not only can Windows use Remote Desktop features, but other systems can also be used, and Remote Desktop functionality can be implemented on the same platform or across different platforms. By default, the RDP server listens on TCP 3389 ports for communication.
The RDP server software is now running as a "Remote Desktop service" service in Windows, formerly known as "Terminal Services", which is now known as the "Remote Desktop Connection ", formerly known as" Terminal Service clients ".

Referring to Remote Desktop, there is something more similar to it, that is, Telnet. Telnet is a command-line form of remote login tool, which, functionally speaking, is somewhat similar to, but in fact, a lot different.

Remote Desktop is very fast, even if the bandwidth is not high, but also good performance, the key is on this protocol, the RDP protocol is located on TCP/IP, but it itself belongs to the OSI layer of protocol. The lookup is not well defined, and it is estimated that the TCP protocol should be used directly at the transport layer.

The early development of computers in the case of many client hardware is not high enough to run the program independently, the Telnet protocol came into being, he is a C/s mode, the client can log on to the high-configuration server through Telnet, run the program on the server. When the program runs all the operations and storage are given to the server to complete, when the end of the operation of the server to return the results back to the client, so that the client can not be configured enough to complete the operation of the program, and the results of the operation is not slow.
Remote Desktop Connection is the development from the Telnet, the popular saying that he is a graphical telnet. So we'll talk a little bit about telnet when we explain the use of Remote Desktop connections.

2. How to use Remote Desktop

① Pre-condition

② use in the intranet

Use of ③ in public network (penetrate intranet)

3. Remote Desktop Web Connection

4. Security for Remote Desktops

5. Other platforms and 3rd party software

Second, the virtual machine program