Virtual machines - why?

There has been a lot of talk about having virtual machines in different threads lately.
I am not famileer with them. Can some one explain to me what they are, why would I want one, and how to get started with them?

Thank you.

Basically VMs give you a computer within your computer.

So if your VM craps out for some reason or another, you can recover really easy as your physical (host) machine is still alive and well.

If you create multiple VMs, say to isolate software then you can have different environments setup pending what you are need rather than putting everything you could possible need on your host machine.

Most will have the host machine just handle "business" type applications. MS Office, Autocad (performace reasons), anything else you need day-to-day. For development, you fire up your Rockwell VM, or your Wonderware VM, or any other VM you may need.

Downside, licensing. You need a license for the OS of the virtual machine. Just because you have Windows on your host doesn't mean you get run Windows in a VM for free (Exception, Windows 7 Pro users can run Windows XP).

And then there are website devolpers that get 90 days for free

https://developer.microsoft.com/en-us/microsoft-edge/tools/vms/

The biggest issue is managing OS licenses for me. To be 100% legal, one needs a OS license for every VM. AFAIK. The only exception is if your organization have enterprise volume license. While we do have VLP with Microsoft, a question to IT gets the "uh, you want to do what?"

Last time I checked, if you have windows enterprise, you can have up to four RUNNING VM's and unlimited not running VM's. Last time I checked though, I lost more than a few hair cells trying to work out the windows licencing model... I will start my own rant in my head about windows server licencing and CALs.

For me I use them to segregate different types of projects. For me I deal in Siemens 95% of the time, but we do have a few AB/Rockwell pieces of equipment.

The RS is all on a VM, because I rarely use it(obviously because AB stuff is way better ), and I don't want it running in the background unless I intend to use it.

VMware is pretty nice, if a VM is something you need/want, check them out.

We are using VM's to keep old equipment running. Our management doesn't understand the value of updating hardware or software. So when a Windows 98, or 2000 machine craps out, and we can't get the software to run on a newer OS, we resort to installing the old OS as a VM and running it that way, which opens a whole nother can of worms...

If I am using the VM on the host only. Then I should be able to use the windows license that is used on the host pc.

Some software insists on running processes in the background, some software insists on grabbing and holding on to the serial port and you have to find the process and turn it off so another set of software can access it, some software 'infects' the hard drive with a million files in all different places.
If these run in a VM when you shut the VM down problem solved without any issue.
the files that 'infect' the computer are also just contained within the VM and do not cause any issues with your main machine.
I also have a second hard drive where all my files are backed up - there is no rubbish on it and it is easy to backup.
I also do a clone of my c: drive every couple of weeks in case of a failure - this also backs up the VMs as well but I do not have a load of rubbish from VMs on the main c: drive.
Just easier.
The only disadvantage is the VMs generally do not support the high resolution of my monitors so I have to sort of work in a smaller window.

NetNathan said:

If I am using the VM on the host only. Then I should be able to use the windows license that is used on the host pc.

Click to expand...

This is where it gets tricky. Obviously MS wants you to pay for a Windows license on each one, but a lot of people have a VM for each piece of software. For example, different FT View versions. To license each one of these would be very expensive.

Here is Microsoft view on VM licensing...
file:///C:/Downloads/Licensing_Windows_Desktop_OS_for_Virtual_Machines.pdf

NetNathan said:

Here is Microsoft view on VM licensing...
file:///C:/Downloads/Licensing_Windows_Desktop_OS_for_Virtual_Machines.pdf

Click to expand...

We can't see files on your local hard drive. You need to upload it.

phuz said:

We can't see files on your local hard drive. You need to upload it.

Click to expand...

OOps...
Here is link to page...see bottom of page for License pdf.
https://www.microsoft.com/en-us/Licensing/learn-more/brief-windows-virtual-machine.aspx

As you read thru the licensing yes and nos plus all the scenarios....At the bottom of PDf there is this....which indicates to me that I can have up to 4 VMs running at the same time using my existing Windows License.
So I can have multiple VMs on my PC... but I can only run 4 at the same time. (It would be nice to have a laptop powerful enough to handle 4 VMs at once

Scenario:
Local Windows
Virtual Machines

Description:
An organization has a group of
developers who need to test an
application across multiple Windows
images running in local virtual machine
on PCs running Windows 10 Pro.

Licensing Solution:
The PC or the primary user of the PC needs
active Windows Software Assurance, which
permits running up to four virtual machines
concurrently.

Easily done. My W530 is no super computer, but its got an i7 and 24GB of ram. I've run 4 VMs on it in the past; however, using a virtual server (esxi) is a great way to go, and it can be done relatively cheap too. If interested, google ESXI, Intel NUC, and Synology.

At least...now we know that if you are running the VMs on your pc then you can use the Windows OS license that came with the pc?

Now...who makes the best VM? Of course this applies to ease of setup.