Is this VM needed if I'm using Linux? I'm not sure what I'm gaining from doing this.

VM is a shortcut for Virual Machine and it is a way of executing code for high level languages such as Ruby, Python, and for instance Java.

High level languages are characterized by the fact that they are much slower in execution than the low level ones (such as C), that is manly due to the fact that, example, by VM they are compiled to bytecode, instead of binary code.The advantage of that is they are easier to use, and more understandable (overally, that kind of a language is more human readable).

In other words, the high level way of doing things is a bit longer to be executed, and the chucks of information are bigger, harder to be processed, need to have fictional virtual machine, to use something machine doesn't use. Because, unlike binary code, bytes don't directly go to the CPU's Arithmetic Logic Unit that crunches these numbers. The kind of a binary code that low-languages use, on the other hand, is compiled by compilers, there is no dynamic way of doing things, you write the code, and need to use compiler; no interpreter or virtual machine allows you to do that on the runtime, dynamically. This is why C is a static programming language, it is not run on runtime by virtual machine.

The way Virtual Machine works, for instance, is:

---> SOURCE CODE ---> BYTE CODE ---> VIRTUAL MACHINE

Moreover, The difference between Virtual Machine and Interpreter is that Interpreter executed/interprets the code one line at the time from the source. It is opposite to continous work done by Virtual Machines, that reduces the initial interpretation lag. In short, VM is a fictual machine that runs the programming language environment on runtime to compile byte code, using instructions by method known as just-in-time, also called as dynamic translation. It is designed to combine interpretation with premature code execution, which is called ahead of time compilation.

So, explaining the above arrow example of how VM works; Source code is compiled ahead of time to the bytecode, and then undergoes just-in-time compilation to the code readable by machine (virtual machine code). On the runtime, only a specific, small portion of a progoram is executed this way, this reduces performance lag, compared to running a program all over again, line-by-line execution of Interpreter.

VM aims to improve performance of a given language, when compared to an ordinary Interpretation.

Hope that it helped.

I'm pretty comfortable in figuring things out on my own and I have Rails version 4.1.5 installed. So I'll go ahead and just do without the virtual machine (I know what one is).