Virtual Machines (VMs) Operating Systems are Software that allow the users to control the Hardware Windows, Unix, Linux, Mac OS, Solaris and many others Operating Systems also known as OS The Operating System that your computer came with, is called the HOST Operating System. The purpose of this writting is to easily explain what is a Virtual Machine, what is it used for, and how to install it. If you want detailed explanations about Virtual Machines, contact the corresponding manufacturers listed below. The most popular current (May 2025) Virtual Machines work on the following OS: VirtualBox Windows Linux Solaris Mac OS VMware Windows Linux Solaris Mac OS Hyper V Windows       Parallels Mac OS       UTM Mac OS         A Virtual Machine, also known as a VM, is a software system, that allows us to install multiple Operating Systems in a HOST computer, using the HOST hardware. Operating Systems installed inside Virtual Machines are called Virtual OS. You can install multiple Virtual OS inside a Virtual Machine (VM). You can also have multiple VMs inside your HOST OS. How Regular Computers Work A HOST computer contains its own OS, and its hardware such as Monitor, hard disk, mouse, keyboard, camara, etc. You can create multiple users in a HOST computer, such as you, your brother, your father, your mother, etc. The main problem with this setup is that if any user allows a virus into the computer, ALL users will get infected with the virus. Benefits of Virtual Computers 1) Cost. If you want to have multiple VMs in one HOST computer, you need to install a Virtual Machine software, and in it, you can install multiple Operating Systems, each independent of each other, all Virtual OSs use the same hardware that the HOST computer has, including the Internet access and printers accessible to the HOST. 2) Security. If any of the Virtual OS gets a virus, all other OSs including the HOST wil NOT be affected by the infected Virtual OS, unless you created tunnels/connecting paths between Operating Systems. 3) Maintenace. If a Virtual OS becomes unstable you can delete it without affecting all other Virtual OSs or the HOST OS. 4) Creation/Cloning. Installing your master copy of an OS can take hours, however once you have a Virtual Master OS created it can take less than 15 minutes to create a new installation from your master, by cloning it. All Virtual OS Can Be Cloned. Let`s install a Virtual Windows and name it WindowsMaster. Do all the OS updates and install all the basic software you need. Now use your WindowsMaster VM to clone/create new Windows Virtual machines. You can do the same for any Operating System. 5) Moving. VMs can be moved to other HOST computers to be used at their new locations. A Virtual OS is just a folder in your HOST computer, cloning simply copies the master folder to a new folder for the new Virtual OS. 6) Space. If you need to use Linux but you have a Mac or a Windows OS computer, you do NOT need to buy another computer, just install a Virtual Machine and a Virtual OS in one machine. If you are using a laptop then you would only need to carry one laptop with multiple Virtual Operating Systems. 7) Research. If you need to create a network with a server and multiple nodes to test systems, you do NOT need to buy multiple computers, you can create a Virtual network in one computer, like a laptop with multiple Virtual Operating Systems and Virtual Machines. Problems with HOST Computers 1) Lost of Power or Connectivity. If a HOST computer losses power or connectivity to the network, all Virtual VMs get disconnected. How do we Install the VM First find out if your HOST computer's OS is running in 32 bits or 64 bits Download your preffered Virtual Machine. I mostly use VirtualBox for many reasons, it always works, it also allows me to run VMware Virtual OS, and it is FREE. Install your Virtual Machine Now using your OS disk, install it in your Virtual Machine, the VM will ask you how much disk space and RAM you want to give to the new Virtual OS you are installing. Every Virtual OS can have different amounts of hard disk and RAM assigned to it. I have seen installations with 6 terabytes of hard disk storage and 128 gigabytes of RAM. In these HOST computers we can install dozens of Virtual OS/users allowing the users to connect to them from the outside via the internet or a local intranet. These installations provide great benefits to the owners and the users. The cost of one HOST computer/server is a lot less than having dozens of separate computers. The hardware maintenance, upgrades, and backups are a lot less expensive. The amount of space is much less, the electrical and air conditioning costs are highly reduced. Adding new users or replacing a damaged Virtual OS is much faster and less expensive. For the users being able to access their Virtual OS from anywhere at anytime is priceless. I believe that this route our industry is taking, will increase productivity at all levels and reduce costs greatly. This is a simplified view of what Data Centers do, and are known as "The Cloud" The current largest provider of Cloud services is Amazon, one of his clients is Netflex. There are other providers like Microsoft Azure, Apple, HP, Intel... If you have any comments please email me at: michael.robinson@cs.fiu.edu -Michael Robinson