Questions tagged [virtual-machine]

A virtual machine is an emulation layer between a program and the OS that presents to the application a specialized environment to run in, than the raw environment that the OS provides.

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Paravirtualization and process virtualization: with or without hardware support?

In Tanenbaum's Modern Operating Systems, fourth edition, about virtualization: Are Virtualization without HW support, Virtualization with HW support, Paravirtualization, and Process virtualization ...
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VCS a Vagrant box [closed]

I have two computers (1 Laptop with Ubuntu that I use for development in 99% of my time but I also have a pretty much unused PC with Windows. I also have an unused server machine at home. I would like ...
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If using a VM as a development environment, should tooling live inside the VM or on the host?

There are a couple of questions already here for whether or not a VM should be used as a development environment. I don't wish to answer that question here but I'm assuming that a VM should be used as ...
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Unique_ptr to hold memory for custom VM

I work for a company that use a custom DSL and my job is to port the VM to C++. I'm trying to do this in compliance with the C++11 standard so i use auto when appropriate, the new for syntax, etc. ...
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Why does a bytecode VM use stack or registers opposed to direct operations? [duplicate]

I'm working on a simple bytecode interpreter to learn how virtual machines work. I've read about VMs and it seems that all of them are either stack based or register based. At the time it made sense, ...
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Is the JVM “heap” inside the JVM software, or inside the physical computer?

I wanted to as this question about VMs in general, but focused it to JVM implementations only so this doesn't get closed as too broad. The JVM has a concept of a "heap". If my understanding is ...
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how to combine logs coming from multiple virtual machines for processing?

Scenario: Two virtual machines produce logs. I want these logs to be sent to a central server for processing (as soon as a line of these logs is generated-->streaming ). The condition here is that I ...
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Prevent product key from being used on multiple virtual machines

I have a software product. it will probably run on VMs that have no network connection at all. I want the user to pay for each VM the user runs. I thought to ask the user for some kind of hardware ...
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4answers
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Why do VMs not execute the assembly directly?

Many VMs execute a language of binary form, knows as 'bytecode', which is assembled down from a human readable 'assembly' language. For example the assembly instructions push 1 push 2 add are ...
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1answer
178 views

Is my 'variable-storing area' basically a 'heap'?

I'm planning to implement a simple VM/interpreter kind of thing for a simple language I'm making. The compiler of the language emits mostly stack-oriented instructions to be executed by the VM. The ...
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781 views

How does a stack VM manage with only one stack?

Lately I've been asking a lot of questions here about VMs. Here's another one: I understand that often stack based VMs use only one stack - the call stack - for everything. E.g. it is also used for ...
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What would the register-machine bytecode for this code look like?

I hope this kind of question isn't off-topic on this site. I'm finally getting the hang of what a stack based machine is, and how to compile code for it. For example, the following code: 2 * 5 + 1 ...
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2answers
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Do VMs use one stack for everything? [duplicate]

Most VMs have a "call stack" to keep track of where to return from each function that was called. This is often simply regarded as "the stack". However often a stack is needed for operations that ...
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1answer
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How do VMs implement function calling?

I'm reading a compiler textbook that compiles to some form of assembly. Since I don't know this assembly language I decided to invent my own simple "assembly language" and implement a basic "virtual ...
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2answers
905 views

If statements in “generic” assembly?

I'm reading a relatively 'friendly' and simple book about compilers named "Let's Build A Compiler" (originally a series of articles). The compiler written in the book generates instructions in some ...
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2answers
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Flaws in my PHP development setup - sharing sources causing lags

I have following development setup for my PHP projects: Working station running on Windows 7 with PhpStorm IDE. GIT for version controlling. CentOS on virtual machine (VirtualBox) with Apache and ...
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Modern.IE VM license

Microsoft provides some VMs for testing purposes (advertised on Stack Overflow) and I'm trying to understand the license terms. The one I don't really understand is 1.b. You may use the software ...
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Why do VMs need to be “stack machines” or “register machines” etc.?

(This is an extremely newbie-ish question). I've been studying a little about Virtual Machines. Turns out a lot of them are designed very similarly to physical or theoretical computers. I read that ...
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2answers
591 views

Does a vm implemented in garbage collected language need a garbage collector?

This is more of a theoretical question. If jvm is implemented in go which itself is a garbage collected language, then does that jvm need a separate garbage collector to be implemented for its own ...
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5answers
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What happened to VM based deployments?

Watched some MountainWest RubyConf 2014 talks and noticed an interesting theme. Many dynamic programming environments back in the old days used to be self-contained VM images, e.g. SmallTalk, GemStone/...
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Developing a virtual machine / sandbox

I'm interested in learning how a virtual machine/sandbox actually works. I have developed an 8051 emulator and also wrote a dissassembler for x86, so this part of a virtual machine is not really the ...
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Are there programming languages that their programs don't run on a VM or natively, but rather on an interpreter? [closed]

In this question I presented an idea I have for a simple programming language. The way programs written in this language will be run, is inside an interpreter written in Java, which will interpret the ...
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Would this interpreter be considered a Virtual Machine? [closed]

(I reworded my question to make it more specific). Consider a programming language, that it's programs may only be run inside a specific program that serves as an interpreter. The interpreter scans ...
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Virtual machine for a high level programming language vs an operating system

It struck me recently that a virtual machine for a high level programming language is very much like an OS. It manages resources, e.g. stack, heap, etc. similar to how an operating system manages ...
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4answers
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What exactly is Virtual Machine Bytecode? [closed]

I want to work on a very simple compiler for a very simple language. The compiler will compile the code to some basic bytecode. Later, a virtual machine program will run the bytecode, and execute the ...
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Speed difference between VM-based and compiled code [closed]

Not so long ago I was told by a senior academic that, these days, VM-based code could run nearly as fast as compiled code, but my own experience is that compiled code runs several orders of time ...
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How do I explain to my boss what a 'Virtual Machine' means? [closed]

Most probably my boss didn't write a single word on a keyboard in his entire life. He saw computers and he has a cell phone. He is a smart man. How can I explain to him what a 'virtual machine' is? ...
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Limitations of using Hyper-V Virtual Machine as .NET Development enviroment

I've been thinking of using a Hyper-V Machine as instead of physical computer for installing my .NET / Azure / Xamarin / ASP.NET / Windows Phone development tools. That way I could easily move from my ...
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2answers
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Is virtual machine image a good protection for source code?

We have developed an application that is sold as an online service. After some time we realized that some of customers would need/prefer/require to have it installed locally on their intranet. However ...
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Why not free memory as soon as its reference counter hits zero [duplicate]

A lot of languages like Java and C# have garbage collectors that free memory when that memory no longer has any reference. Yet they don't immediately free it after the reference counter hits zero but ...
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Interpreter or virtual machine that does not execute bytecode

The developers of the Dart language tell that there is a virtual machine that executes statements written in Dart language. What is the difference between an interpreter and a virtual machine that ...
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2answers
309 views

What is the advantage of a programmers VM apart from portability [duplicate]

I can understand the benefits of Java running on a JVM. Portability. Nice simple reason. But I have always been puzzled as to why Microsoft brought out their own version of a JVM - .NET. C# is ...
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What's the relationship between meta-circular interpreters, virtual machines and increased performance?

I've read about meta-circular interpreters on the web (including SICP) and I've looked into the code of some implementations (such as PyPy and Narcissus). I've read quite a bit about two languages ...
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What is the job of a language virtual machine, and creating one [closed]

Recently I have become incredibly interested in language development. The past few weeks I have written many language front ends (lexer, parser) including a calculator language/expression parser and ...
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1answer
441 views

Representing floating-point numbers in bytecode

How do interpreted languages typically go about representing floating-point numbers in their bytecode? For example, suppose I've got a Java program with the line double a = 3.0; What does 3.0 look ...
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Which are the alternatives to using a stack to represent function call semantics?

We all know and love that function calls are usually implemented using the stack; there are frames, return addresses, parameters, the whole lot. However, the stack is an implementation detail: ...
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How did the term “hypervisor” come into use?

I've read about the "hypervisor" in hardware virtualization. VMs are not my area, so I can't quite see where the term came from. THe wikipedia article talks about how "the hardware's supervisor ...
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Are there any reasons not to accept a software deliverable as a virtual machine?

This is a question about logistics, not a technical question. My company has outsourced some embedded software work. Specifically, we have payed a contractor to develop an embedded system for us ...
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1answer
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Setting up a development environment in the cloud? [closed]

I'm interested in transitioning my development environment onto the cloud. I currently use VirtualBox with Vagrant to manage separate virtual machines for each individual project. What would be the ...
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1answer
555 views

Difference between language virtual machine and emulating vm?

I'm having a hard time understanding the difference between an emulation virtual machine and a language vm. I started with the research and implementation of an emulation virtual machine. Primarily ...
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Which are the fundamental stack manipulation operations?

I'm creating a stack oriented virtual machine, and so I started learning Forth for a general understanding about how it would work. Then I shortlisted the essential stack manipulation operations I ...
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1answer
365 views

Is there a way to get the version of Ubuntu that Google uses for development? [closed]

Is there a way to get the version of Ubuntu that Google uses for development? Even better would be a full up VMWare or Virtual Box Virtual Machine image that might include a full complement of ...
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Why would more CPU cores on virtual machine slow compile times?

[edit#2] If anyone from VMWare can hit me up with a copy of VMWare Fusion, I'd be more than happy to do the same as a VirtualBox vs VMWare comparison. Somehow I suspect the VMWare hypervisor will be ...
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How to devise instruction set of a stack based machine?

Stack based virtual machines like CLR and JVM has different set of instructions. Is there any theory behind devising the instruction set while creating a virtual machine? e.g. there are JVM ...
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6answers
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Why aren't there other programming languages that compile to Python bytecode?

In Java, there are multiple languages that compile to Java bytecode and can run on the JVM -- Clojure, Groovy, and Scala being the main ones I can remember off the top of my head. However, Python ...
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671 views

Isolated environment for software stacks

I was sure that I would find this question, but I couldn't. How to create an isolated development environment? It other words, a sandbox, where I can install different combinations of web servers, ...
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1answer
595 views

Virtual Machines And Unit/Integration Testing Web Application

I am in the process of adding unit testing to a project I am working on at work and a suggestion came up that I should use VMs to populate the database with good data. This was suggested as an ...
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1answer
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Architectural considerations for a new black box program

I see an emerging trend in "cloud" computing to move work load to a third-party server and get charged pennies for amount of work done in this way. This could be anything from file hosting to user ...
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7answers
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Java IDE written in pure Java? [closed]

Is there a Java IDE written in Java? I just got my year 9 DET laptop today at school, and there are all sorts of restrictions set in place. Somewhat annoyingly, you cannot run any executable other ...
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1answer
358 views

How to deploy a heterogeneous server application to customers?

We have a bigger application server which customers would like to have deployed locally. It consists of an MySQL server database, a REDIS database, multiple Web servers for sub parts, a NGINX reverse ...