Why use a virtual machine?

Why use a virtual machine? -- Linux general technology-Linux technology and application information. For details, refer to the following section. I. Students and beginners

Since the computer development is so fast, many students are learning from Windows 98 and Windows 2000 when learning computer science. They are not familiar with MS-DOS, Windows 3.x, and NetWare. In this way, when a student's computer fails, he or she does not know how to solve the problem, because he or she does not know how to solve the problem. For example, if a small fault occurs, the Windows 98 computer cannot be started because there is a non-boot disk in the soft drive. At this time, he did not know to take this disk out of the soft drive and then restart the computer.

Students may have learned some computer (History) knowledge, also know to start the disk, also know MS-DOS, also know to format the disk, also know that the hard disk before use partition, format, you also know that the software needs to be installed .......

The students learned too much from books, but few of them can practice it by themselves. Because:

1. the school data center is installed by the administrator of the data center. Generally, the machine in the data center does not allow students to install their own systems. Even more, students are not allowed to partition hard disks and Format hard disks, this is intolerable and unrealistic in schools.

2. even if students have their own machines, the configuration is very high, but few students partition, format, and frequently install new systems on their own machines. If they partition and format the hard disk, the machine will not be used for a long time. If you want to learn tools and software, you won't use your own machines to do experiments, especially some "dangerous" experiments.

3. Students only have one machine and cannot perform network experiments. At most, they can perform online experiments. Even if a few students put the machine together for an experiment, it is not easy to find the site, power supply, that is, Nic, switch and other things are not good configuration.

Nowadays, most of the students talk on paper, because if the learning knowledge has not been tested, they can only stay in theory. Not only do employers prefer those with practical experience, but they will also think that this is not the case. When I used to teach MCSE students, I heard that some students who passed the seven MCSE exams did not even know the NIC. This is not a joke.
"Practice is the only criterion for testing truth". Without practice or hands-on operations, you cannot learn, learn, or learn essence.

In a virtual machine, you can perform every experiment with confidence and boldness.

2. Computer enthusiasts

Because of our hobbies, we always like to use the latest software for the first time, use the new operating system for the first time, or try to use multiple systems. If you use the latest software on your machine, the system may be unable to start or be vulnerable to viruses. If new system software is used, it is more likely to be faulty, because it is easy to damage the hard disk and lose data when the new system is installed. You know, computer hardware is relatively valuable, but your data is priceless in many cases. Even if you are a computer expert, you may encounter errors when testing new systems.

One of my colleagues installed Linux on his machine to learn about Linux. Before installation, he found another hard disk and prepared to install Linux on the second hard disk. He inserted this hard disk into the main IDE port to set it as a slave device, and set the MASTER hard disk (its original hard disk, in the main IDE port, to MASTER) to none in CMOS. He uses a linux CD to boot the installation from the optical drive. However, during the installation, the Linux system "automatically" re-partitions the hard drive and "Format. Because, although the master hard disk is set to "NONE" in CMOS, Linux, Windows2000 and other systems will also detect the installation. His data in a few years was all over. At that time, he had a jump to the building .......
Now, with the virtual machine, you can install various software in the virtual machine. You do not need to install a new system every day to test the software. when testing the system software, you do not have to worry about our valuable data. Doing experiments on virtual machines is all true. The results are exactly the same as doing experiments on real computers. At the same time, you can be completely assured that you do not have to install the system carefully.

3. Network Administrator

Because it is a network management service, it is necessary to maintain the security of the enterprise network, so that the enterprise's network is not subject to external attacks. At the same time, we must make full use of the network function to serve and stand up for the enterprise. At this time, we need to often test some patches and some network software. If physical machines are used, hardware may be damaged, it may also reduce network security (If you test software on your computer, you may run Trojans or hacker programs ).

If I ask you whether you have performed network or network experiments, you will surely laugh at me. Who has not done network or network experiments in these years. In this sentence, I would like to ask one hundred people engaged in computers. at least 60 people have said that they have established networks. As long as they have been engaged in computers, most of them have established networks. So, I ask you, have you ever created a cluster, and have you ever performed any cluster experiments? If I use this sentence to ask one hundred computers or even 100 specifically engaged in computer networks, I can say for sure, no more than three people have performed cluster or cluster experiments.

We know that Windows 2000 Advanced Server supports the "cluster" service, but few people have conducted cluster experiments because the experiment costs too much (to do a cluster experiment, at least two cluster hosts and one shared SCSI memory cabinet are required, which requires at least two or 0.3 million RMB ). Now, you can perform cluster experiments on VMware virtual machines. This is the secret of VMware ", this book exclusively discloses this function, introduces the experiment methods, and provides corresponding tools.

4. diskless enthusiasts

Being a diskless workstation is once a symbol of a master, but it is not easy to become a master. Because: first, the experiment environment is hard to find, because in the process of creating a diskless workstation, you not only have servers, workstations, NICS, switches, but also boot chips. However, some NICs do not have the corresponding boot chip. Second, the quality of diskless workstation is better, because in some cases, after the installation and configuration of the same batch of diskless workstation are complete, some can be started, and some cannot be started. If this is your first lab and you happen to have a faulty workstation, you will be "miserable", because you may think it is a problem, it is not considered that the server or workstation is faulty.

Therefore, to become a master of diskless workstation, you must have a relatively stable network environment, a software and hardware environment, and correct installation and configuration instructions. The installation is successful for the first time, you probably know how it works. When you install and debug it, you will not make any mistakes.

In vmwarevirtual machine, can do PXE Windows 98, Windows ME diskless workstation experiment, can do BOOT-NIC diskless Windows 2000, diskless Windows XP, Windows Server 2003 experiments, you can perform experiments on diskless workstation of 3COM VLD and 3COM DABS, and terminal experiments of Windows 2000/Server 2003 and Citrix MetaFrame 1.8/XP.

V. Enterprise Users

Many enterprises, for historical reasons or other reasons, each department has a server, or several important departments have servers. These servers have a single function and fewer applications, but these applications are different. They cannot coexist on one server. Previously, you had to configure only one server for each of these departments, which virtually increased hardware investment and management costs. Now, enterprises are facing the upgrade problem. You cannot purchase another server for each department. But how can you save the original service? One-step upgrade is not realistic and requires a process. You can install the VMware gsx server or esx server on a high-end SERVER, and then install multiple virtual servers on the gsx server or esx server, assign a virtual server to each department. These virtual servers are no different from the real servers. In this way, hardware investment and management and maintenance costs are reduced.

6. software programmers, APS programmers, and web designers

A program compiled by a programmer needs to run in multiple environments and multiple systems. In the past, programmers can only find multiple computers or install different environments on one computer repeatedly (single-host environment, network environment, different IE versions, and other issues, database environment, etc) or multiple systems (such as Windows 98, Windows ME, and Windows 2000. After the webpage is uploaded to the website, the webpage designer does not know the end user's use environment (for example, IE5.0 or IE6.0 ), to avoid problems, before uploading a webpage, the webpage designer tests each IE version or between different surveyors. In the past, web page makers used to find different people and computers in different environments for testing. Now, with virtual machines, you can use them on a computer, you have installed Multiple virtual machines and configured multiple environments to perform tests on your own. This helps you identify and quickly report problems.

VII. education, computer writers, computer editors, etc.

When teachers make courseware, writers need a large number of pictures when writing. Some pictures can be captured directly under the system, but some pictures, such as entering the CMOS settings and restarting the computer, how to capture it? Shooting with a digital camera? This is not only troublesome but also ineffective. You can directly use the virtual machine to capture the Virtual Machine window. When editing a review, because there are a lot of content written by the contributor, you can verify the content in the virtual machine when editing a review, because the machine editing the review cannot be random.