Re:A Virtual Machine
by chubot on Friday April 06, 2018 @05:14PM
(#16777516)
OK no problem, it would be interesting to see a comparison between the two styles of VM! I remember that there is at least one talk here which goes into the difference:
I forget what the different names he used. He distinguished between runtimes like the JVM and runtimes like Xen, which emulate an operating system too. A CPU emulator seems closer to Xen than the JVM.
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EDIT: The names were "system" and "process" VMs, mentioned here:
So I think you are talking about a "system VM", where this book is more about "process" VMs. They are related, but distinct -- it even says so in that book's title!
It's definitely true that in something like Xen you would want to avoid allocating memory more than in something like a JavaScript VM. (And it would be easier to avoid allocating, too.)
I don't like that terminology, but it's a useful distinction.
http://soft-dev.org/events/vmss16/
I forget what the different names he used. He distinguished between runtimes like the JVM and runtimes like Xen, which emulate an operating system too. A CPU emulator seems closer to Xen than the JVM.
-----
EDIT: The names were "system" and "process" VMs, mentioned here:
https://news.ycombinator.com/item?id=16777564
So I think you are talking about a "system VM", where this book is more about "process" VMs. They are related, but distinct -- it even says so in that book's title!
It's definitely true that in something like Xen you would want to avoid allocating memory more than in something like a JavaScript VM. (And it would be easier to avoid allocating, too.)
I don't like that terminology, but it's a useful distinction.