Talk:QEMU/Archive 1

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Archive 1

How?

According to the blog of a kernel hacker, [1], QEMU does some pretty interesting stuff to manage what it does. But I'm afraid her summary made little sense to me, and I could not get the paper she referenced. A 'how' section is a necessity, I think. --Maru 05:38, 1 September 2005 (UTC)

Hardware drivers?

It is noted as a disadvantage that it doesn't have special drivers for the guest system, but isn't it close enough that it emulates existing hardware, so its drivers can be used in the similar fashion? I've added that info, but I believe all that could be completely removed from Disadvantages because of that. However, as I am not sure about that, I won't touch it, and some more opinions would be welcome here. --Arny 14:44, 5 April 2006 (UTC)

Having special drivers for the guest system could provide better I/O performance. For example, drivers included in the guest system would probably have small delays between byte writes in order to accomodate speed requirements of real hardware. But the delays are not really neessary for hardware that is emulated, and just are wasting time. There are other types of inefficiencies that come from needing to emulate real hardware (the guest OS drivers encode and pack data into bit structures, then QEMU's hardware emulation layer needs to unpack and decode the data again to interpret it). -- Bovineone 05:23, 6 April 2006 (UTC)

Knoppix 4

Can somebody post "the string" to run Knoppix 4 in Qemu in Windows XP? renegadeviking

It would probably be something along the lines of qemu -cdrom knoppix.iso -boot d -m 128 – try running qemu without any options for the complete list. The examples provided here are intended mainly as very general examples, and they intentionally don't list any specific operating system distribution – don't want WP:SPAM, do we? (Note – those examples were posted based on how it works on my own Linux system, so I'm not sure if you'd need any extra options for Windows...) — Martin Ultima (multima)   •   talk   contribs   leave message 16:25, 6 August 2006 (UTC)

Paravirtualization?

Why the article said that KQEMU uses paravirtualization? As KQEMU is closed source who knows that for sure? And I'm personally doubt that it is. 217.26.163.26 11:43, 18 January 2007 (UTC)

  • Hmm, you're right. That was my brain fart -- it looks like KQEMU changes QEMU from a type 2 to a type 1 hypervisor. I'll remove the para* reference, but please feel free to add your own wisdom.  :)  ◉ ghoti 15:29, 18 January 2007 (UTC)

kqemu is now GPL

quite recent, but kqemu is now gpl 2... wish I could update and reword article, but *woosh* off to movie cinema I go... —The preceding unsigned comment was added by 203.214.42.225 (talk) 06:17, 6 February 2007 (UTC).

yes kqemu is open source now. The article is outdated.--Hasanidin 22:10, 6 February 2007 (UTC)

contradiction

"This is accomplished by running user mode and virtual 8086 mode code directly on the host computer's CPU"

"and should theoretically benefit from KQEMU's speedup, if KQEMU supported VM86 mode which is not the case."

which one is correct? Plugwash 12:43, 13 February 2007 (UTC)

Neither really. I've updated appropriately. AnthonyLiguori

license factual details

I don't know if this is true. http://fabrice.bellard.free.fr/qemu/license.html says QEMU is under lgpl, only the accelerator module is proprietary. --71.198.173.255 09:39, 4 February 2007 (UTC)

Even the kqemu (accelerator) module is GPL now. Robert Brockway 19:19, 15 February 2007 (UTC)

VMware uses virtualization

It says that VMware doesn't do virtualization, right? If so, then that's not correct. Boches and non-accelerated QEMU are emulated at the CPU level. VMWare Workstation and the accelerated QEMU try to run as much code natively as possible. If you want sources for this information, please go to the websites of QEMU and VMWare or just compare their speeds to Boches and plain QEMU! —The preceding unsigned comment was added by JWhiteheadcc (talk • contribs) 23:41, 11 March 2007 (UTC).

Merge Qemu-Launcher ?

Looks like an old tag; it would be nice to see it go. Anyone care whether Qemu-Launcher gets merged into this article? I lean towards a yes, but I'm not a quorum; if I can see three or four more votes that aren't a no, I'll do the merge.  ◉ ghoti 03:29, 16 January 2007 (UTC)

Yes - I feel that though they are a little different, they are really the same, so I feel that they should get merged. Voted by:TheEgolf 00:28, 18 January 2007 (UTC)

No - They are very different as one is an accessory of the other. I've been using Qemu for about 2 years and only heard of Qemu-launcher just now so it is hardly a necessary component. Qemu is a complicated tool and adding another tool in to the article would only confuse things. Robert Brockway 16:28, 15 February 2007 (UTC)

No - I really don't think it belongs in this article, and it's not as though this is the only front-end for QEMU. --StuartBrady (Talk) 18:07, 15 February 2007 (UTC)

YES - I don't think that it's notable enough on its own. I think what would be a good idea is to have a separate section on different QEMU front-ends (there's another KQEMU unrelated to the virtualizer that actually runs it from KDE, and then EWOK), and if any of them becomes significant in its own right it can be forked into a separate article. Martin Ultima [ multima - talk - contribs - leave message ] 04:04, 17 February 2007 (UTC)

YES - As per Martin Ultima's comment. --Witchinghour 15:50, 12 March 2007 (UTC)

YES But only as a link to an article with a list of frontends. Otherwise, NO. JWhiteheadcc 12:14, 13 May 2007 (UTC)

Yes - the launcher is pointless without the thing it launches, and in this case it's only notable (if it is at all) because of QEMU itself. I also agree with Martin Ultima's comment regarding front-ends.  ◉ ghoti 18:23, 27 May 2007 (UTC)

FMOD

I moved the comment about the Windows version using the FMOD sound layer from the shortcomings section and included it with the comment about the (L)GPL, where it belongs. I left the note that points to the FMOD site, though I'm not so sure it belongs considering I found no note of QEMU there. BioTube 14:49, 18 June 2007 (UTC)

Grammar

"Wine windows API reimplementation and DOSEMU are the main targets for QEMU in user mode emulation." -- The use of "targets" here is ambiguous. Could someone who understands what this sentence means please reword it appropriately? —Preceding unsigned comment added by 68.100.224.150 (talk) 02:29, 31 December 2007 (UTC)

qvm86 death

I believe the development ceased (even officially) much earlier than 2007 and before it was known that Vbox would be released.Balrog-kun (talk) 18:20, 29 May 2008 (UTC)

...and does not, therefore, fully qualify as free software.

In the first paragraph "It is free software, but when running on Windows uses the proprietary FMOD library, and does not, therefore, fully qualify as free software." Could someone familiar with various "free software" licences make this more specific? perhaps a citation or two? Cuvtixo 04:16, 19 September 2007 (UTC)

If you consider FMOD a component of QEMU on Windows, then you would surely also consider this is a GPL violation -> "and does not, therefore, fully qualify as legal software" :-) If you don't consider FMOD a component of QEMU, then QEMU for Windows, as a whole, is licensed under the GPL. The individual source files are under a variety of licenses, but QEMU as a whole is distributed under the GPL[2]. --StuartBrady (Talk) 09:46, 19 September 2007 (UTC)
Well FMOD isn't a major component of the operating system. So yes it is almost certainly a GPL violation (if you belive the FSFs interpretation of the GPL with regard to dynamic linking). Windows ports of OSS apps do this sort of thing all the time and generally noone cares too much (the linux versions are checked for freeness by the linux distros, but no such checking happens for the windows ports). Plugwash (talk) 04:01, 21 January 2009 (UTC)

Copy on Write feature listed

The page lists a feature known as copy-on-write. Here is what the page mentions:

"Implements Copy-On-Write disk image formats. You can declare a multi-gigabyte virtual drive, the disk image will only be as large as what is actually used."

This sounds a lot more like sparse disk images rather than copy-on-write. Is there any reason why I shouldn't replace "Copy-On-Write" with "Sparse"? If not, I'll make the change.

Blutrot (talk) 03:41, 21 January 2009 (UTC)

Afaict the format supports both Plugwash (talk) 03:59, 21 January 2009 (UTC)
In that case, I'll leave it for now. Blutrot (talk) 00:26, 22 January 2009 (UTC)

User mode emulation

Does the said section talk about user mode emulation at all ? --Jerome Potts (talk) 05:43, 6 August 2010 (UTC)

What programming language was QEMU written in?

I noticed that the infobox in this article doesn't mention the programming language that QEMU was written in. Will this information be added? Jarble (talk) 20:51, 11 February 2013 (UTC)

Why is SDL a shortcoming

Under “Shortcomings”, it is listed that it “only” supports SDL and Cocoa as video output.

I can’t thing of any reason why this shouldn’t be enough. — flying sheep 08:02, 14 June 2013 (UTC)

Hi. You are right but that's not the only problem. The whole section reads like a list of "things that I, the author, don't like". That's why criticism sections are for the most parts not allowed in Wikipedia. I suggest this section should be merged with the rest of the article when appropriate (e.g. in case of no UEFI support) and deleted when not appropriate (e.g. in case of "less-frequently used" weasel word).
Best regards,
Codename Lisa (talk) 09:00, 14 June 2013 (UTC)

Clarification to first sentence

The first sentence needs a touch more info to clarify the point. I suggest that it is a performance related issue, as suggested by the section in the article on hardware-assisted virtualization.

I suggest adding "which offers better performance" so the sentence should be:

QEMU (short for Quick Emulator) is a free and open-source hosted hypervisor that performs hardware virtualization (not to be confused with hardware-assisted virtualization, which offers better performance).

http://stackoverflow.com/questions/12597607/what-is-the-difference-between-hardware-and-hardware-assisted-virtualization

Phersh (talk) 18:39, 12 July 2015 (UTC)

That would be misleading. QEMU performs hardware virtualization and uses hardware-assisted virtualization where possible. --Stefan Weil (talk) 19:12, 12 July 2015 (UTC)

3D support

The article used to say that

As of 2014, QEMU does not support 3D acceleration (work-in-progress [1]).

However, in 2015-12-16 QEMU 2.5 was released with "support for interfacing with the VirtIO 3D GPU support for allowing accelerated OpenGL via guests" [3]. So I have edited out the excerpt above. I am not sure about this, however, because http://virgil3d.github.io/ (the reference for the excerpt I edited out) still says that

It is not ready for distribution.

Please someone more knowledgeable sort this out. -- Jorge (talk) 13:48, 13 January 2016 (UTC)

References

  1. ^ Airlie, Dave. "Virgil 3D GPU project". Virgil 3D github page. Retrieved 2014-10-13.

Integration with other virtualization solutions: WinUAE

Emulation of PowerUP (accelerator) cards in WinUAE (and FS-UAE) Amiga emulators is based on QEMU code. Is it worth/notable enough to include such information in this section?Pavlor (talk) 12:19, 27 February 2016 (UTC)

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How do you pronounce it?

Can someone add the good way of saying "QEMU"--195.137.113.186 10:31, 9 May 2007 (UTC)

I've always split it q emu and pronounced the q as the name of the letter and the emu like the first sylable of emulator but i've no idea if this is correct or not. Plugwash 13:53, 9 May 2007 (UTC)

I've always read it as "que(ue) emu(lator)" or "Queue-Ee-Em-You" (Q-E-M-U), but it would be nice to be sure. Have you tried looking here? http://kidsquid.com/cgi-bin/moin.cgi/QemuDict Or here? http://qemu-forum.ipi.fi/ If all else fails, you can post a new question there and leave a link here. JWhiteheadcc 12:11, 13 May 2007 (UTC)

This is answered in the QEMU FAQ.  ◉ ghoti 18:36, 27 May 2007 (UTC)
The faq is a little confusing to read in regards to the subject but it seems like [kyoo-EM-yoo] is how it is supposed to be pronounced. — Preceding unsigned comment added by Fsabelhaus (talk • contribs) 15:46, 10 April 2012 (UTC)

I pronounce kh-emju.5.47.46.40 (talk) 13:50, 19 January 2013 (UTC)

In the OpenStack cloud Nova team meetings I hear it pronounced 3 weeks: Key-Moo, Q.E.M.U., and Kwee-Moo. 2017-09-14 — Preceding unsigned comment added by Medberry (talk • contribs) 19:37, 14 September 2017 (UTC)

Quick Emulator

Timeline:

  • 2011-05-29: Claim that QEMU is short for "Quick Emulator" is added, with 2008 citation
  • 2011-09-29: Claim was removed as being "trivia"
  • 2012-03-27: Claim was re-added, without citation
  • 2018-01-18: [citation needed] is added; "Can't find an official source for this, only third party sites that may just use Wikipedia as a source. Additionally, some evidence that Fabrice has not said anything about the title."
  • 2019-10-01: A 2019 citation is added

I first went ahead and removed the 2019 citation--it smells way too much like citogenesis. I then dug through the page history, and found the original 2008 citation, and re-added it--ok, at least that citation predates the claim appearing in the Wikipedia article. But then I marked it dubious, because yeah, if it really were short for Quick Emulator, we should be able to find an official source for that, and we haven't.

https://web.archive.org/web/20030421114656/http://fabrice.bellard.free.fr:80/ is the oldest Wayback Machine snapshot of Bellard's homepage that mentions QEMU. Note that it identifies "QEmacs (for Quick Emacs)", but says nothing about "QEMU" being for "Quick Emulator".

~ LukeShu (talk) 16:57, 31 May 2020 (UTC)

Has been removed. 2406:5A00:B40B:3800:699B:E7BB:DFF:15B2 (talk) 14:34, 27 September 2021 (UTC)

Windows support

The article says "incomplete support for Windows" but I've found no problem at all installing and running multiple versions, including Window XP Professional using the latest QEMU on x86. Same with all the conventional apps. Of course, accelerator makes the performance tolerable. --Phil Smith

This problem I know existed in 0.6.1. CVS had the fix for a while, and now the 0.7.x series is perefectly able to boot XP. --Reub2000 21:43, 14 August 2005 (UTC)
I believe what the article means by "incomplete support for Windows" is as a host OS, not as a guest OS. I believe the free virtualization module does have a windows version as well, so I don't know if it holds true at the moment. Anyways, the non-fullsystem emulation (for running binaries) is Linux only as far as I know. Rvalles 08:11, September 1, 2005 (UTC)
I know it used to have incomplete Windows support – I think that's why it's there, the article was originally written when QEMU was still in its early stages – but since I haven't used Windows in well over two years now, I honestly wouldn't know... if it's running better, go ahead and change it (if you or someone else hasn't already). — Martin Ultima (multima)   •   talk   contribs   leave message 16:19, 6 August 2006 (UTC)
I use it with no problems on Windows since I started using QEMU at the beginning of the 2006. I do believe the mentioned sentence is unnecessary. --Arny 04:44, 29 December 2006 (UTC)
Maybe the phrase "incomplete support for Windows" was referring to the kqemu kernel accelerator module, in particular the '-kernel-kqemu' switch which can't do 16-bit processing causes Win9x to crash with a "Windows protection error." Yet qemu can run Win9x without the '-kernel-kqemu' switch. This information more properly belongs in the kqemu article. --AC 04:24, 23 September 2007 (UTC)
Ironic as it may seem, under newer versions of Windows 10 as a host, the only guest OS that run flawlessly in QEMU Windows builds, is Windows XP. Linux guests have many difficulties to install, and in many cases, the installations are inoperable. — Preceding unsigned comment added by 78.90.203.18 (talk) 07:06, 3 December 2021 (UTC)
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