What's a VM?

Yesterday I discussed the VM/ESA Handbooks and how I had a chapter in one of them. I confess it was a very proud moment when I got a copy of the book. I remember sharing the news with friends from church, not that they were really into VM/ESA, or even computers in general. One of my friends, a young  lady, in support of me picked up the book and declared that she would read my chapter, which started with:

VM is an ideal platform for understanding application performance.

Looking up from the book, she asked, "Ok, so what's a VM?".  Well, now isn't that question at the heart of things in these reflections? I admit that at the time, I really struggled to answer her question.  I was handicapped by not having a white board to use; and I wasn't quick enough to think to say, "You will need to read Chapter 1 for that." I believe her background was something like early childhood development, not electrical engineering. (Though, early childhood development could come in handy when dealing with unreasonable co-workers or customers).

We have lots of ways to explain VM these days. There's even whole presentations devoted to it. A virtual machine is an amazing thing and future posts will look at some of the things I find most exciting about them. But in ways, the amazement doesn't overwhelm until you learn about how it's used.


The analogy that comes to mind is from back in grade school when we learned about simple machines: lever, pulley, wheel, inclined plane, wedge, and screw. While interesting as individual items, the amazement grows exponentially when they are combined and enhanced. So with this model, I sometimes take a different approach and describe the complex first. Point out that their bank ATM transactions are validated on software in a virtual machine. The website they are surfing on runs in a virtual machine. That purchase they just made is getting routed through virtual machines. The processing of records for their court appearance next month will be with virtual machines. The paycheck they're cashing to pay for the court fee was connected to a virtual machine. In the end, they may not have a better understanding of what VM is; but hopefully it will help them understand the value of VM.



I don't want anyone thinking I'm calling VM simple. And simple should not be confused with unimportant. Take out all of the simple machines inside a Ferrari Enzo and it's not so impressive. Take VM out of enterprise solutions, and they won't be impressive either.


In case you were wondering, my friend never finished the chapter, but she still thought it was cool that I worked on something that had books devoted to it and that I was part of that. I have to agree.