What is the antonym of 'virtual machine'?

A virtual machine (VM) is a piece of software pretending to be a piece of hardware. There can be virtual servers, virtual desktops...

I googled around a bit and did not find anything.

I am creating a list that has Servers, Desktops and Virtual Machines; where Servers & Desktops are understood to only include non-VMs, I need to add two more items to the list

  • Severs VM & (virtual machine antonym)
  • Desktop VM & (virtual machine antonym)

I need a word to replace "(virtual machine antonym)" I was thinking "Hard" but not sure that is appropriate.

The Audience is IT Professionals.

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    'Antonym' is ill-defined for an 'A-type B' (a virtual-type machine). Is it a non-A-type B? a non-A-type non-B? ... – Edwin Ashworth Sep 2 '14 at 14:33
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    Well a true antonym would be something like "actual person". What you want is likely more properly called the complement (or even converse) of "virtual machine". – RBarryYoung Sep 2 '14 at 18:36
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    @EdwinAshworth "Antonym" may be "ill-defined" in the general case, but how seriously did you consider the possibility that OP wanted a phrase that meant "physical things that are not machines"? – Kyle Strand Sep 2 '14 at 21:31
  • (Though I'll concede that @RBarryYoung's suggestion of "complement" is preferable.) – Kyle Strand Sep 2 '14 at 21:32
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    Not every word in English has an antonym. – LessPop_MoreFizz Sep 3 '14 at 2:43

Let's consider a definition of a virtual machine:

A virtual machine is a software computer that, like a physical computer, runs an operating system and applications. The virtual machine is comprised of a set of specification and configuration files and is backed by the physical resources of a host. Every virtual machine has virtual devices that provide the same functionality as physical hardware and have additional benefits in terms of portability, manageability, and security.

Out of this definition we explicitly see an antonym physical computer. But i would use physical machine instead. And if we surf the web, we find the usage quite common:

A physical computer (sometimes called a physical machine or a physical box) is a hardware-based device, such as a personal computer. The term is generally used to differentiate hardware-based computers from software-based virtual machines (VMs). (Source)

"Virtual Machine to Physical Machine Migration - VMware" (PDF document)

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    Yes, the usage P2V and V2P is quite widespread. – Ben Voigt Sep 2 '14 at 15:50
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    This is a bit blurry though, with modern hardware support for virtualization, and with minimal hypervisors. A virtual machine may actually be using a lot of the hardware directly (or almost directly) these days. I still agree with this answer, though. – Joshua Taylor Sep 3 '14 at 23:59
  • It is true that is much fuzzier today than maybe 10 years ago. It's very common anymore for an operating system to run on a hypervisor, even though the machine is dedicated to running that specific OS instance. Even real machines are unreal. – Hot Licks Sep 4 '14 at 19:38

Before the widespread use of VMs, in the context of server hosting, we used to call this simply a 'dedicated server' to differentiate between that and a 'shared server'.

Today, I'd be inclined to call it a 'bare metal server' if you were going to allow the customer to install whatever OS they wanted. (as 'bare metal' effectively means 'computer without an operating system'. (see the Jargon File entry)

Digging further into the Jargon File suggests 'real' as the antonym to 'virtual', but I'd be more inclined to use Matt Gutting and Othya's recommendation of 'physical' before I used 'real' in this context.

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    Among computing professionals, "physical" is the most common antonym of "virtual" and generally considered the formal choice. "Real" is rarely used formally, and is generally treated as more casual or even slang. – RBarryYoung Sep 2 '14 at 18:47
  • Virtual Machine Host and Virtual Machine Guest are antonym So it can be abbreviate as VM Host & VM Guest Turn the word "virtual" in VM into physical makes no sense in my opnion – WingTillDie Sep 3 '14 at 14:46
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    @user3268410 : "Virtual Machine Host" assumes that you're running a hypervisor ... when you're running a server OS without virtualization, it makes absolutely no sense. – Joe Sep 3 '14 at 15:21
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    I hear the term bare metal used frequently in the software industry. – Casey Watson Sep 4 '14 at 3:40
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    "Real" as an antonym of "virtual" applies to memory, traditionally. The very first virtualization to become common on computers was memory, and the terminology was pretty much always "virtual" vs "real". But, while this usage carried over to an extent for devices (eg, real vs virtual printers), not so much with processors (though there the distinction was often "physical" vs "logical"). – Hot Licks Sep 4 '14 at 19:41

The phrase I've most often used by engineers as the anytonym of virtual machine or virtualised environment is bare metal.

Though in practice, this is almost always used in a sentence which contrasts it with running in a virtual environment. The phrase also carries connotations of running on a platform without a hypervisor.

Example sentence: No, our app isn't running inside a virtual machine, it's running on bare metal.

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    I disagree with this use of "bare metal". IMO it means something like "without operating system" in the context of computer software, basically implying some kind of embedded system without OS, for example an Arduino board. So your example is kinda non-sequitur, sort of like "our car isn't running on a tarmac road, it is running on gasoline". – hyde Sep 4 '14 at 16:48
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    @hyde I've never heard that usage before. Perhaps it's a different usage for the same phrase? The usage I quoted is one I hear several times a week in the wild, so it's definitely normal in my idiolect. – Racheet Sep 4 '14 at 17:28
  • I guess language develops, "bare metal" is not a formal term anyway. But I think this "virtual machine antonym" usage illogical. It could be antonym of "emulated machine", but a "user space" application on a usual VM is running as much (or as little) on "bare metal" as same application without that extra virtualization layer. From application code perspective, the VM hypervisor isn't doing much more than virtual memory manager does on every modern OS. "Bare metal" to me means, application has access to the bare metal without the OS killing it if it tries. – hyde Sep 4 '14 at 18:08
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    To complement what I say above, I would agree with the usage "The operating system is running on bare metal, not in a VM". In that case the distinction is real: is the OS controlling the bare metal (memory mappings etc), or is it just controlling the VMs emulation of these. – hyde Sep 4 '14 at 18:21

You could consider real machine, taking a cue from the existing references to real memory and virtual memory.

Like a virtual machine, real memory is implemented in the most efficient way in terms of time performance. Generally this is done by using the RAM (random access memory) directly. Virtual memory is functionally identical to real memory (at some level in the software functionality) but it is implemented in a less performance-efficient way, using emulation, using other hardware, such as a hard drive (or even using a tape in the old days).

Both real memory and virtual memory use physical hardware.

A real machine is implemented in the most performance-efficient way, which is to have a processor and all of the related computer peripherals implemented as purpose-made to implement the required functionality. A virtual machine implements with less performance efficiency because there is added emulation functionality to implement the virtual machine in the hardware.

Both real machines and virtual machines use physical hardware.

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  • You could consider this, but it is not actually in use in this sense, while physical machine is. – reinierpost Mar 8 '17 at 11:27

Couldn't be simpler, "physical server"

(Or indeed just ...... "hardware". I hear ten times a day "Should we use parse.com or hardware, should we use a bAAs or hardware.") (I realise aws etc. is indeed implemented on, of course, hardware at some level :) but the sense is obvious.)

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  • PS Ben has already pointed out that P2V and V2P are widespread – Fattie Sep 2 '14 at 15:56

I believe physical machine is your best bet, but an alternative could be Host Environment. The Operating System that runs on a Virtual Machine is often called the Guest OS while the Operating System that runs on bare-metal is often called the Host OS. A Guest OS runs in a Guest Environment while a Host OS runs in a Host Environment.

This isn't as good as physical machine because it would only be understood in certain contexts, but it is an alternative.

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Sometimes we say "Native Machine" or "Native Architecture". Java bytecode is the Esperanto of programming languages as it has no native architecture and always runs on a "Virtual Machine". This is applied to emulation often as we have Qemu style synthesisation of legacy or cross-platform targets.

Some virtualisation is strictly speaking, containerisation (Docker, Xen, LXC, chroot). It is also possible for instruction sets to match and to run purely virtual.

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  • No ... native machine or native server is never used, native is a term reserved for code. (Native code is code executing on the physical machine rather than on a virtual machine.) – reinierpost Mar 8 '17 at 11:28
  • I may have meant for the -march=native switch and similar usage. But cross platform development still occurs, I suppose the correct term there is "target" machine. In the old days we would say "physical" for non-vm. It is getting harder to define virtual without a hypervisor. Is DosBox a VM ? What about Wine ? I withdraw the term "Native" as I concede the point. Besides cross assembly, GO64 was the first time I saw this at a consumer level. – mckenzm Mar 9 '17 at 2:33

Any software program, no mater how complex, can be written as a combination of these three boolean operators: AND, OR, and NOT.

And it just so happens that these operators have physical counterparts known as logic gates. These logic gates are in fact exactly how some micro processors work.

From this, we see that the previous answers given here by other people are actually correct: a physical computer can be thought of as the antonym of a virtual machine.

However, let's not stop at this simple answer. Let's take this knowledge further.

Since any program can be represented by the AND, OR, and NOT operators; and since these software building-blocks have physical counterparts; we can therefore say that it is possible to make a physical circuit with all the functionality of a given computer program.

And since a "virtual machine" is nothing more than a sophisticated program, it too can be modeled by an electric circuit — albeit a very big and unreasonably-expensive circuit.

In colloquial terms, one may suitably refer to such a circuit this as a "hardwired program".

This terminology bears allusion to devices like the [hardwired controlled unit][3] which, in the past, were used as faster alternatives to microprogrammed devices.

In short, we can say that a "hardwired program" is an electronic circuit which performs a particular function not by interpreting software instructions, but rather by being an exact physical representation of the software itself.

Essentially, it's a piece of hardware "pretending to be" a piece of software. :P

Some Notes:

Besides the improved performance, such hardwired devices can have improved security and reliability, which are important in some high-grade applications. For example in reliably generating a normal distribution of random numbers — which is, by the way, a more difficult problem than it may seem.

It's also worth mentioning that very early video games were actually implemented directly into the hardware due to the performance benefits that this provided.

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    I can see this does eventually answer the question. You might have gathered fewer downvotes if you had provided the result ("hardwired program") earlier and then explained how you got there. You don't need anything extraneous like your "Some notes" section. You may find that editing the answer will allow downvoters to revise their opinion, and/or additional upvotes to appear. – Andrew Leach Sep 4 '14 at 6:40

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