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What is a virtual machine and what is it for?

A virtual machine is a program that allows you to emulate a real computer with all its components (BIOS, HDD, drive, etc.). Any operating system, software and drivers can be installed on this virtual PC. You can freely exchange data between your real system and your virtual one.

I will not say that absolutely every user needs a virtual machine, but an advanced user often needs it. A virtual machine is used for various purposes and tasks:

• To install another or a second same OS;
• For testing various software;
• To emulate a computer network;
• To run applications that cannot be launched from your OS.

To give a specific example, for example, your PC has Windows XP, and you can install Windows 7, Windows 8 or Linux on a virtual one.

In this article, I will talk about three popular emulators, their main features and the advantages of each of them. I will present as a bonus Android emulator for Windows and I will give an example of creating a virtual machine using one of the emulators as an example.

VMware is one of the most famous and widespread virtual machines. It is usually used large corporations... VMware comes in two flavors: Player and Workstation, the first of which is free and the second is paid.

VMware also supports 32 and 64 discharge systems, as well as USB 3.0 and various OS.

Key Features:

• VMware allows you to connect USB devices, CD / DVD disks, network interfaces, and others to virtual machines;
• Supports moving and copying files using drag and drop;
• You can connect new virtual machines using a step-by-step wizard;
• You can create a virtual machine using an installation disk or from a ready-made disk image;
• VMware Player supports virtual machines that were created on paid VMware.

Microsoft Virtual PC

Microsoft Virtual PC is a free virtual machine with a user-friendly interface and great functionality. The only small drawback is that only Windows operating systems are supported.

Key features:

• It is possible to select the hardware that is needed in the virtual machine;
• You can add or remove hardware on a virtual computer;
• You can copy virtual machines;
• I have an opportunity fast switching between virtual PCs using bookmarks;
• It is possible to drag and drop files from the main PC to the virtual one and vice versa;
• You can connect virtual and real computers over the network.

VirtualBox

VirtualBox is a free emulator on which you can install the most popular operating systems such as Windows, Linux, FreeBSD, Mac OS. Both 32 and 64 bit versions of operating systems are supported. Also VirtualBox can work with virtual computers that were created in paid program VMware Workstation.

The main features of the program:

• VirtualBox can be controlled both through the graphical interface and through the command line;
• VirtualBox allows you to connect USB devices to virtual computers and allows them to work with them directly;
• All parameters of the virtual machine are described in XML format and therefore do not depend on the physical PC on which the system is running;
• VirtualBox supports remote control;
• There is a special SDK for extending the functionality of the program.

After analyzing the reviews of all three emulators, we can conclude that VirtualBox is the most suitable program for creating and managing virtual machines. Therefore, we will consider the installation of a virtual machine using VirtualBox as an example.

Installing the VirtualBox virtual machine

Let's take a look at how to install VirtualBox, and in the next chapter, we'll see how to set it up.
Download the latest version of the program from the official website or from our Download the program
We launch the installation and see the first welcome window. Click “Next” and go to the next stage.

At the second stage of the installation, we see the components of the program that will be installed and the directory into which the program will be installed. The installation directory can be changed, but it is recommended to install all components. Even if not all components are needed right now, and in the future they will be needed, then you will need to reinstall the virtual machine.

At the next stage, a warning appears about the temporary disconnection of the computer from the network during installation.

Then a window will appear with a message that you can start the installation. Press the "Install" button and wait for the installation to complete.

During the installation process, pop-up windows may appear that say “Install software for this device? " Click the "Install" button.
When the installation is over, click the “Finish” button. The virtual machine will automatically start after the installation is complete.

Creating a VirtualBox virtual machine

In order to create a virtual machine, you need to in the window VirtualBox programs click on the "Create" button in the upper left corner.

At the first stage, enter the name of the machine to be created and select the type of operating system. For example, let's create a virtual machine with the Windows 7 operating system. Let's go further.

At the second stage, we set the amount random access memory which is required for the virtual machine. We install it based on the needs of the selected operating system. V system requirements Windows 7 is specified to require at least 1 GB of RAM. Let's specify, for example, 1.5 GB. Here you need to take into account that you cannot install more than half of the RAM of a physical computer to a virtual machine.

Now you can connect to the created virtual machine virtual hard disk. Let's create it first. Select the item "Create a new virtual hard disk" and click on the "Create" button.

Specify the type hard disk... If you are not familiar with the formats described there, you can leave it as it is and click “Next”.

Now you need to specify the format for storing data on the virtual hard disk. A dynamic virtual hard disk can expand, but a fixed one has a strictly defined size. Choose as you like best.

We indicate the name of the virtual hard disk and its size. Click “Create”.

Setting up a VirtualBox virtual machine

Let's see what settings the virtual machine has. Click the "Configure" button in the upper left corner of the program.
The settings window appears. Here you can change various parameters of the virtual machine (for example, the amount of allocated RAM, enabling 2D acceleration, device boot order, etc.)
All settings are divided into categories.

If you make a mistake in the settings, the program will inform you about this by appearing in the lower part of the settings window the inscription “Incorrect settings found”.

Usually the first 3 categories of settings are enough for the user. If the virtual machine is running slowly, you can increase the amount of RAM or use more processor power.

After completing the settings, click the "OK" button. To start (turn on) the created virtual machine, click on the "Start" button. Now we insert into the drive installation disk with the operating system, install and configure the operating system and your virtual computer ready to use.

That's all, we looked at 3 popular emulators, identified all of them strengths, chose the most suitable for us, installed and configured a virtual VirtualBox machine, and now the promised Bonus.

BlueStacks - Android emulator for Windows

BlueStacks Player is a program that allows you to run Android applications on a Windows or MacOS computer. BlueStacks allows you not only to get acquainted with the capabilities of Android, but also to fully test applications created for this operating system. By using emulator BlueStacks users will be able to install and run on their PC any of the many programs available in Google play, GetJar, Amazon Appstore, 1Mobile and other online catalogs of Android apps. Best of all, BlueStacks is completely free.

Key features of BlueStacks

The most important feature of the BlueStacks emulator is its support for LayerCake technology, which simulates an ARM processor. This technology allows Android applications run on x86 processors. The ARM graphics subsystem is also imitated, which makes it possible to run on BlueStacks the most modern games that are written for Android tablets. The finger navigation that tablet users are accustomed to can be done with the mouse on BlueStacks.

Unlike other virtual machines, BlueStacks does not need to install the operating system manually - everything Android functions available immediately after launch. One setting you need to do is change the interface language. The Russian language is fully supported.
BlueStacks runs on Windows 7, Windows Vista, Windows XP.

This is where our today's review ends. Good luck with emulation.

Virtualization allows you to encapsulate internal organization operating systems or parts thereof inside virtual hardware and software... In other words, create a virtual space that will be real from the point of view of the operating system running in that space. This is exactly what virtual machines for Windows 7, Linux and Mac OS X do. Virtualization also allows you to simulate devices that are not on your computer at all.

Note: In a sense, virtual machines allow you to create a computer inside a computer.

There are two important aspects of machine virtualization:

• interaction between physical host (computer) and virtual host
• interaction between the operating system running in the virtual space and the hardware used

Virtualization software, namely virtual machines for Windows 7 (Linux, Mac OS X), is usually a common application or operating system service that allows you to create hosts. Any physical machine (computer) is called a host. Inside virtualization software, the operating system runs in a similar or identical real host called a virtual machine. For convenience, the operating system running in a virtual machine is referred to as a guest operating system.

In addition, there are different ways virtualization, on which not only the implementation of applications for creating virtual machines depends, but also the provided capabilities for guest systems. There is the usual emulation, in which hardware and software calls go through the middle layer. There is also para-virtualization, where part of the actions inside the virtual machine takes place on real hardware, while the other part goes through the intermediate layer. And also there is virtualization at the system level, when each guest system is loaded in a special kernel, which allows you to run only similar versions of the operating system.

Some of these methods can be performed on the fly, without significant changes to the real host and its operating system. Others require rebooting the host into a special instance of the operating system that supports virtualization. Others use dedicated hosts that support and are designed for virtualization at the hardware device level. The latter are also known as virtualization techniques on bare metal (although this is not entirely true, since some software kernel is still used).

Virtualization software that manages the creation and operation of virtual machines, as well as the allocation and limitation of the resources provided, is often referred to as a hypervisor. Some virtualization applications can also use special processor extensions to improve the performance of virtual machines. The presence of such extensions is called hardware virtualization support. Examples of this support are VT-X (Intel) and AMD-V (AMD) technologies.

What is not virtualization and virtual machine?

Some people like to call virtualization programs (virtual machines) anything that creates a layer of abstraction between the operating system and some of the running processes. For example, there is Sandboxie, which allows you to isolate browsers from the system (see browser protection utilities). Some programs allow you to freeze the state of the system so that it cannot be changed. Others also allow you to use the so-called shadow mode, in which all programs run normally, but any changes are canceled when the computer is restarted.

Of course, all of these programs provide various benefits, but they are not considered virtualization technologies and are not virtual machines because they do not imitate system calls and they do not allow you to run guest operating systems on top of the current system. Such programs only create additional layers of separation, mainly to increase the level of security. Continuing the topic of security, then ...

Why use virtualization and virtual machines?

If security comes first for you and this is the first thing you think about in any situation, then virtualization (using virtual machines) can certainly help you with this. But, don't assume that virtualization is primarily used for security purposes. Its primary goals are testing, cost reduction, flexibility, legacy product support, and education. Increasing the level of security is only nice bonus, which has many pitfalls of its own.

Note: Although virtualization allows you to isolate one operating system from another, there are still ways to get from the guest system to the main one.

What does it take to run virtualization technology and virtual machines?

The first thing to consider is the physical host. Depending on the type of virtualization software (virtual machines), completely different hardware and operating systems may be required. Virtualization does not imply any one solution that will run wherever you need it. Virtual machines need to be selected for the system (Windows, Linux, Mac), and for the hardware (hardware). In addition, the host must have the requisites.

So if you are going to run guest operating systems on top of your system, you will need additional resources to run them, such as CPU and RAM. For example, if your computer only has 2 GB of RAM and you want to run the guest system on Windows 7, then you will have to severely limit resource usage on the real system for the virtual machine to function properly. Unless you're trying to run Windows XP with 256MB of memory, of course. However, if you have 16 GB of RAM, then you can run more than one guest system without feeling any lack of resources.

Pros: Easy to install and use.

Cons: Limited functionality. Doesn't support snapshots and general access to directories.

Virtual Machine for Windows 7, Linux and Mac OS X - VirtualBox

VirtualBox is another cross-platform virtual machine creation program for Windows 7 and higher, as well as Linux and Mac systems, currently owned by Oracle. VirtualBox is similar to VMware Player but has more features, including a more advanced networking stack, unlimited snapshots, some OpenGL and DirectX support, and much more. The app is easy to install and just as easy to use. You can also use the command line for automatic deployment. VirtualBox also supports USB and shared directories. In addition, there is a portable version of VirtualBox. However, there are also disadvantages. You cannot take screenshots of guest systems. Disk management is somewhat confusing.

Audience: beginners and advanced users.

Pros: Easy to install and use, many features.

Cons: No support for screenshots, importing existing machines is difficult, not intuitive disk management.

VMware ESXi hypervisor for creating virtual machines

ESXi is a bare metal hypervisor with reduced functionality compared to ESX. The application requires a host and can be controlled from the console (the console is locked by default, but you can manually enable it). You will not be able to take screenshots or capture video from the screens of your virtual machines. Guest migration and cloning is done manually only. But, on the other hand, you get memory sharing to improve the efficiency of the use of RAM, powerful control and management, and access to the command line via SSH (when unlocked). You can also install VMware Tools to improve the performance of virtual machines. Para virtualization is also supported by ESXi.

Pros: Powerful, advanced virtual machine capabilities.

Cons: Requires a host and a lot of resources. Not easy to install and run.

Virtual Machine for Unix / Linux - Kernel-based Virtual Machine (KVM)

KVM supports virtualization only for UNIX-like operating systems (Linux). The application can be run on any hardware or in emulation mode, however, without processor extensions, the performance will be terrible. KVM is intended to be used over the console. But, it has a decent management interface that lets you start and stop virtual machines, take screenshots, and more. The interface is known as Virtual Machine Manager (VMM) and is also used to manage Xen virtual machines (see below). Support for local and remote control... There is a known conflict with VirtualBox, but it can be solved relatively easily

Audience: advanced users and professionals.

Pros: Full control and flexibility, very high performance, under the right conditions.

Cons: Only UNIX-like systems. Requires virtualization hardware extensions to run properly. Emphasis on the command line. Not easy to install and run.

Virtual Machine for Unix / Linux - Xen

Xen is another application for virtualizing UNIX-like operating systems (Linux). It must be loaded in its own kernel instance. The emphasis is on the command line. But, you can also use VMM. Officially, Xen has been supported by OpenSUSE for many years and was recently added to the mainline kernel release. Xen can run in hardware-assisted mode or para-virtualization. However, for para-virtualization, Xen is highly problematic to install and run. In addition, Xen has limited support for cd-rom and network devices... It is also available as a bare metal virtualization hypervisor on a Live CD. There are numerous third-party extensions for managing Xen.

Audience: advanced users and professionals.

Pros: Full control and flexibility, very good performance, built-in kernel support.

Cons: Only UNIX-like systems. Steam virtualization mode is buggy. Emphasis on the command line. Several utilities command line which can be misleading. Not easy to install and run. You must load your own kernel instance.

Other solutions for creating virtual machines

There are many other solutions not listed here, such as Parallels Virtuozzo, OpenVZ, and VMLite-based VirtualBox. There are also a number of redesigned solutions, including examples of crossing virtualization and thin clients... Linux also has a huge number of its own modifications. And don't forget about cloud technologies with their virtualization applications.

Nevertheless, if you are a novice user, then you should not chase the possibilities and colorful modifications. Otherwise, an attempt to create a virtual machine to run a couple of three programs can turn into several sleepless nights.

A few words about virtualization programs

This review will be useful not only for novice users, but also for experts. The listed products cover a wide range of virtualization technologies at all levels. All solutions described are free for personal use. Choose what you want or need based on the available hardware, requirements for ease of setup and launch, as well as the presence of the required set of functions.

Typically, most people start learning about virtualization with VMware Player or VirtualBox. Linux users might prefer KVM and possibly Xen. Experienced users might want to take a look at ESXi.

To have several operating systems with a separate workspace and applications at hand, you do not need to buy a second (third, fourth, etc.) computer. Because it all fits into your only PC. How? Thanks to virtual machines (VM) - special programs that create (emulate) imaginary (virtual) computers inside the main operating system.

The virtual PC is almost like a real one. It has its own processor, memory, hard drive, network adapter and everything else. Of course it is not physical devices, but they are made in such a way that the operating systems consider them just like that - real.

On one physical computer several virtual ones can work simultaneously. How much depends on hardware resources: the faster the processor, the larger the RAM, the more spacious the drive, the more. A typical home PC with average performance Windows based The 10 handles three to five lightweight OSes running concurrently (like Windows XP, Android and Lubuntu + base system). Or two or three relatively heavyweight ones (for example, basic Windows 10 + virtual windows 7 and Mac OS X). As you already understood, virtual computer emulator applications allow you to install and run a wide variety of operating systems on them.

Virtual machines general purpose(as opposed to specialized ones, such as, for example, VM Java), use:

• To run applications that the main system does not support.
• To protect the system from the potential harm of unverified programs.
• As an additional barrier against viruses when visiting questionable web resources.
• To create an isolated environment for studying malware activity.
• As a testing ground for debugging your own developments.
• To master the technologies of building networks.
• For double authorization on some game portals and much more.

And of course, virtual machines are widely used to distribute server working resources.

Today we will not touch upon the industrial application of VM, but consider only what can be useful for home users of Windows.

Oracle Virtualbox

Let's take a look at the process of creating a new virtual machine and starting the installation of Windows 10 into it.

• Click the "Create" button in the top panel.

• In the first window of the VM creation wizard, we will indicate the OS name (it will be displayed in the list of guest systems), its type (Windows, Linux, etc.) and version. In our example, this is Windows 10 32 bit (you can also install 64 bit, but it will require more resources). Click Next to go to the next step.

• Next, we will indicate the size of the VM's RAM. By Windows default 10 x86 is allocated 1 GB, but you can increase this amount by moving the slider to the right. If your PC does not have a lot of RAM, do not give the VM more than 2-3 GB, otherwise the main system will slow down due to lack of memory.

• Next, we create a virtual hard disk. If you are installing the system for the first time, select the "Create new" option.

• Leave the default virtual disk type.

• A storage format is an area on your computer's physical storage that is assigned to a VM. It can have a constant or dynamically expanding volume within the limits that you define further. To save space, we will choose a dynamic format.

• Next, we will indicate the name of the volume (virtual disk C) and its size. The default is 32 GB.

• After clicking the "Create" button in the last window, a new virtual machine will appear in the list. Its parameters are shown in the frame on the right.
• To proceed to the Windows installation, click the "Run" button in the top panel.

• In the window that will open after that, a window will appear “Select boot disk". Click on the folder icon and specify the path to the system distribution kit. It can be an image in .iso format or physical media (DVD, flash drive). After selecting the distribution, click "Continue".

• The further course of OS installation into a virtual machine does not differ from its installation on a physical computer.

Some VM and guest settings

Clicking in the virtual machine window captures the mouse cursor (that is, it will only move within the virtual screen). Press Ctrl + Alt to return the cursor to the main OS.

To access the entire set of functions of the guest OS, you need to install special add-ons. Go to the "Devices" menu, click "Mount Guest OS Additions Disk Image" and follow the further instructions.

To connect a folder to the guest system for sharing files with the main one, click on the "Devices" menu item "Shared folders". Click on the "folder +" icon in the window that opens and through the "path to folder" field specify it in the explorer (it shows the directories of the main system).

If you want the setting to work all the time, check Auto Connect and Create Permanent Folder. a shared folder will be accessible from the explorer of the virtual machine as a network.

To change the order of the poll boot devices(for example, to boot a virtual machine from DVD), shut down the guest OS, open its settings (in the main Virtualbox window) and go to the first tab of the "System" section. In the Boot Order list, mark the media you want and use the arrow buttons to move it up.

VMware Workstation Pro

Some options for Hyper-V virtual machines

To take a snapshot of a running guest OS, open the top menu of its Action window and click Checkpoint. Or press the combination Ctrl + N.

Access to the settings of an individual virtual machine is opened from its context menu in the list of the main window of the dispatcher and is hidden behind the "Parameters" button.

Other features of the program are also very straightforward and are mastered without much difficulty.

Every PC user sometimes wants to try some other operating system, but hesitates to install it on his work computer. Indeed, installing an unfamiliar OS is a very risky act. One wrong command can lose all data on the disk. But today there is a way to test several operating systems on one computer at once, and, if desired, even simultaneously! This method is called - virtual machine or virtual computer... Consider three best programs that allow you to use virtualization technology at home.

Understanding virtual machines

Virtualization systems that exist today have a lot in common. In particular, each virtual machine recognizes a CD drive as well as a floppy drive. In addition, it is possible to work with virtual drives and disk images. Very useful is the ability to manually set the amount of RAM for each of the virtual machines, the list of connected devices, etc. Such flexible settings allow you to comfortably use the guest system. A very convenient feature is the ability to suspend a virtual machine at any time. This frees up the necessary hardware resources for the host system.

All the differences between existing virtual machines, in fact, are reduced only to the list of supported by them operating systems, and cost... Most common today VirtualBox systems, Windows Virtual PC and VMWare. How are they different?

ORACLE VirtualBox - versatile, free virtual machine

VirtualBox- very simple, powerful and free tool for virtualization, developing thanks to the support of the famous ORACLE corporation. Allows you to install as a "guest" almost any modern operating system, be it Windows, MacOS or any of the many representatives of the Linux family.

Creating virtual machines in VirtualBox is done with a step-by-step wizard. Any more or less experienced PC user can understand its work. The system supports networking, therefore, if desired, you can give the virtual machine access to the Internet.

VirtualBox allows you to take "snapshots" of the operating system. With their help, you can create "restore points" to which you can "roll back" the guest system at any time in case of errors or failures.

Windows Virtual PC - a virtual machine from Microsoft

Windows Virtual PC- a virtual machine to work only and exclusively with Windows. Installing Linux, MacOS and other operating systems are not supported.

Virtual PC allows you to run several different copies of Windows on one computer. In this case, you can set them a priority so that in automatic mode allocate more resources for the needs of a particular virtual machine, slowing down the work of the rest.

The monoplatform nature of the Virtual PC virtual machine is its main drawback. However, if you want to test only programs running on Windows, this is not relevant. Some disadvantage can be considered less functional and less convenient interface than in VirtualBox. Otherwise, Virtual PC is quite a reliable tool that allows you to create virtual machines with Microsoft Windows operating systems.

VMware Workstation - for serious tasks

VMware Workstation is a powerful, premium, premium virtualization software that supports Windows and Linux. For virtualization MacOS, this machine is not intended.

Due to its high reliability and the broadest functionality, VMware Workstation is often used not only for testing, but also for the permanent operation of virtual machines as servers, whether it be a firewall that separates an organization's network from the Internet or even a database server.

VMware Workstation is highly configurable, including many hardware options and options network connections to work with the Internet. This system is better than others we can reproduce on virtual machines graphic applications, since it has a special virtual 3D accelerator for obtaining High Quality graphics.

The interface of VMware Workstation is well organized, so it's pretty easy to get comfortable with all its rich functionality. The program fully supports the Russian language.

It should be noted that VMware Workstation has a free "little brother" - VMWare Player. The player does not know how to create virtual machines, but allows you to run previously created in VMware Workstation. This program will be useful in cases of testing, when, for example, a developer automated system will send it for review in the form of a virtual machine image. This practice is becoming more widespread, since it relieves the user of the need to deploy an unfamiliar program on his own.

You can argue for a long time about the principles of virtualization and its role in the IT industry, but the ordinary user will not be of any use. Therefore, I will say briefly. The virtual machine is your sandbox. You can install your operating system in it, install programs, run suspicious files as if it were another computer. Without fear for your main operating system.

So, a virtual machine is a program that can completely disguise itself as a separate computer (emulate). Under it, as on a separate computer, you can install Windows (Linux, FreeBSD, MacOS X) and they will not suspect anything. The operating system that runs in the virtual computer is called subsidiary... You, working with another OS in the program window, are well protected from viruses and your own errors. After all, a virtual computer will not burn out, there is no important data on it, it is easy to restore it at any time.

Child operating systems are much faster if your processor supports hardware virtualization. You can check this using a utility that you can download.

There are quite a few free virtual machines, but we'll take a look at the two most popular VirtualPCs from Microsoft and VirtualBox, recently purchased by Oracle.

VirtualBox

VirtualBox- a free virtual machine with a very wide range of features and excellent performance. VirtualBox officially supports most of the popular operating systems, such as various versions of Windows, Linux distributions, MacOS X, and other operating systems. By supporting hardware virtualization, you can achieve the speed of the child system comparable to the main one. A large set of additional utilities allows you to perform many useful actions, such as restoring the child OS, simply transferring files between the main and child systems, and even translating the program window into the main OS.
The big plus of VirtualBox is that it supports many mobile operating systems such as WinMobile or Android.

VirtualBox

Virtual PC

Virtual PC- a virtual machine from Microsoft, which they provide for free use. It will not work to install an alternative OS on this virtual machine (at least without dancing with a tambourine). There is no official Linux guest support, although many distributions work successfully. But there is simple solutions to install other Windows versions... For example, XP compatibility mode for later versions of Windows.
Virtual PC also supports hardware virtualization, which greatly speeds up the performance of the guest OS.
The archive contains 32-bit and 64-bit versions of Virtual PC. But remember that you can only install a 64-bit guest OS if your main OS is also 64-bit.