Talk:Comparison of virtual machines/Archive 1

What counts?
What counts as a "Virtual Machine". Does something where it is separated from the main operating system, but is still the same operating system and kernel, like chroot, does that count? What about something like user mode linux? Reub2000 19:43, 10 Mar 2005 (UTC)
 * I was debating putting user-mode linux on the list, just for completeness' sake. I created this comparison just to expose similar-purpose products to an apple-to-apples comparison as much as possible, for my benefit as well as others'.  Based on what I know, it looks like user-mode linux would not be out of place here. MARQUIS111 2:47 EST, March 10, 2005
 * To answer your question about what is a virtual machine, to my mind, it is method of running an OS in a protected/isolated environment with virtual hardware created on another OS. There is, of course, a vast crowd of VM's fitting that description, from MAME, to Commodore 64 emulators to CHARON.  This list could have them all, but I'm not adding them. :-) I just put on the ones I'm interested in.  Let someone else add them to this or another table. —Preceding unsigned comment added by MARQUIS111 (talk • contribs) 20:16, March 10, 2005
 * Virtual code execution environments such as the Java or .NET runtime engines might also count as virtual machines. Actually, the Java runtime is often called "JVM" - "Java Virtual Machine". Just a matter of perspective. --80.108.109.173 18:02, 5 September 2007 (UTC)

Confusing section
"Native speed because nothing is running under emulation or any different as it would natively without being under a VM." Am I the only one that finds this confusing? 18:53, 19 December 2005 (UTC)

I don't like the split
I think the comparision should exactly like it was, since so many of the emulators do a lot of archs. Like qemu, which is on both lists. —Preceding unsigned comment added by Reub2000 (talk • contribs) 22:15, March 11, 2005
 * I didn't like it either, the more I looked at it. Just reverted it back. —Preceding unsigned comment added by MARQUIS111 (talk • contribs) 22:18, March 11, 2005

Win4Lin missing
Could somebody who knows about this stuff integrate Win4Lin? —Preceding unsigned comment added by 213.23.130.234 (talk • contribs) 11:24, April 2, 2005


 * Whoever does this needs to bear in mind there are two Win4Lin product lines based on rather different technology. The original Win4Lin for running Win9x/ME uses a very different strategy to the new Win4Lin for running Win2K (which is based on QEmu). Mark Williamson

Supported guest OS drivers
What does the "Supported guest OS drivers" column actually refer to? Drivers provided by the virtual machine vendor? Mark Williamson
 * My intent in putting that column in was to address mainly the Dynamic Recompilation/Virtualization/Emulation camp, wherein dwell VMWare, VirtualPC, BOCHS, QEMU (without kqemu), etc. They offer drivers for selected OS' to speed up performance.  Non-supported arbitrary OS' can run, but not as well. For the Porting-style camp, like XEN and Denali, this would likely be a n/a entry in that field.  I'm not familiar with the others, so I leave that to those who know those products.--MARQUIS111 16:51, Apr 17, 2005 (UTC)
 * Thanks for the response. Either n/a or plain "Yes" (since they not only support but actually rely on custom guest OS drivers) would make sense to me.  I'll probably go through and update the table at some stage (if nobody beats me to it). Mark Williamson 13:45, 19 Apr 2005 (UTC)

USB Support
It would be nice if there was a column for USB support. VMware, for example, supports USB Full Speed rate of 12 Mbit/s (commonly mis-referred to as 1.1), but not Hi-Speed USB. --Elvey 16:28, 19 October 2006 (UTC)

Thankyou !! I fully agree, I just added a new column for people to fill in the details for each VM (I did the first one "BOCHS" myself) but one of the bots removed it ! :-(. Anyway, I added it again as a vein attempt to make it stick :p -- Jonathan Casey (University of Warwick - Computer Science UG)

User Mode Linux is missing
I think User Mode Linux ( http://user-mode-linux.sourceforge.net/ ) deserves some mention here. —Preceding unsigned comment added by 84.131.122.204 (talk • contribs) 18:01, July 14, 2005


 * True, i vote for inclusion, too.
 * Creator=Jeff Dike/Community project; Host Processor=x86 (x86_64 beta?); Guest Processor=(Same as parent); Host OS=linux>=2.4, Officially supported guest OS=linux>=2.4; Guest OS SMP available?=no(?); Runs Arbitrary OS=no; Drivers for supported guest OS available?=yes; Method of operation=??; License=GPL; Typical use=Hobbyist, Developer, Server/Service Isolation; Guest OS speed relative to Host OS=slow, better with SKAS patch on host.
 * &mdash;Nils Toedtmann 12:35, 10 November 2005 (UTC)


 * BTW, what about including Cooperative Linux ( http://www.colinux.org/ )?
 * Creator= Dan Aloni/Community project; Host Processor=x86; Guest Processor=(Same as parent); Host OS=Win2k, WinXP, linux 2.6; Officially supported guest OS=linux=2.6.10; Guest OS SMP available?=?; Runs Arbitrary OS=no; Drivers for supported guest OS available?=yes; Method of operation=??; License=GPL; Typical use=Hobbyist, Developer; Guest OS speed relative to Host OS=slow.
 * &mdash;Nils Toedtmann 12:57, 10 November 2005 (UTC)

coLinux is supposed to be near-native speed, it's not an emulator. from my experience it -is- very fast. —Preceding unsigned comment added by 69.181.176.167 (talk • contribs) 07:18, December 16, 2005

If we start listing emulators, why listing so few...
If we start listing such things as PearPC, why not other emulators, like for example SheepShaver, Basilisk II, or even any emulator existing? I mean, what's the difference between PearPC and Basilisk II that makes that one is listed here and not the other? --SuperBleda 23:29, 13 September 2005 (UTC)

Virtualisation vs emulation and confusion
I thought I understood what virtualisation means. From reading this and related articles I'm now quite confused. I was under the impression the virtualisation is different from emulation and basically means you're running the code as native code on the processor. For this reason, you can only virtualise the native processor. Bochs for example emulates (or something similar) but does not virtualise. This is supported in this page somewhat. But in the virtualization page, it lists Bochs as virtualization software! Furthermore under the entry here for Virtual PC for the Mac, it claims it uses dynamic recomplation and/or virtualisation. I believe dynamic recompilation is possible but virtualisation is not (obviously things will change when we get x86-64 Macs but thats a different issue). If this is correct, this needs to be reworded to make this clear.

Furthermore, the Virtual PC page suggests Virtual PC has always been virtualisation software. Yet virtual PC started off as Mac software, it was only later they brought it to the x86. If my understanding of virtualisation is correct then clearly Virtual PC did not used to be virtualisation software, despite the name and it needs to be made clear. If I am correct, the Virtual PC article also needs to make clear that Virtual PC for the Mac is not virtualisation software. I think Virtual PC for the PC/x86 is virtualisation software but I'm not certain. If it is, obviously the difference between the Mac and PC version needs to be emphasised.

This is quite a technical issue and I clearly don't know enough to correct it. This is why I tagged all 3 needing expert attention. I hope this was okay, it's my first tag. BTW, I think SuperBleda's question is also quite relevant Nil Einne 17:52, 22 October 2005 (UTC)


 * I've just modified Virtual PC, Bochs and this article.
 * I think I've just solved the confusion.
 * &mdash;Claunia 21:50, 22 October 2005 (UTC)

Three tables

 * Virtualization is not the same thing as emulation. This table confuses things by putting them in the same table.  Virtualization is hardware-based.  Emulation is software-based.  Paravirtualization is the term for the stuff inbetween.  I think we need three tables.  That should also help with the columns, since some apply to emulation and some to virtualization and some to where the line is drawn in the hybrid case (paravirtualization). --Treekids 20:32, 24 July 2007 (UTC)

Splitting "xen" into "xen<=2" and "xen>=3 w/ VT"
The actual description of xen is correct for xen <= 2.0.x or any xen on a CPU not supporting Virtualization_Technology. But xen >= 3.0 on a VT-enabled CPU should run any guest os, and it's real virtualization, not paravirtualization. So i vote for giving xen two rows. Nils Toedtmann 11:06, 10 November 2005 (UTC)

AnthonyLiguori: I've updated the page to reflect Xen 3.0 and some recent changes in QEMU. I don't think it's work splitting the Xen section into a 2.0/3.0 since 2.0 doesn't really have a large user base anyway. One thing I removed was part of the footnote about Xen's performance. It compares it do an "advanced chroot" which is really wrong. Paravirtualization is doing at compile time what something like VMware does at run-time (replacing sensitive instructions with something else). Plus, with the recent HVM support, it just leds to more confusion. —Preceding unsigned comment added by 70.116.12.56 (talk • contribs) 15:50, December 17, 2005