Qemu packages for Cygwin?

Qemu packages for Cygwin?

[Dan Shelton]

Hello!

Does Cygwin come with qemu packages?

Dan
-- 
Dan Shelton - Cluster Specialist Win/Lin/Bsd

Re: Qemu packages for Cygwin?

[Marco Atzeri]

On 18/12/2023 07:42, Dan Shelton via Cygwin wrote:
> Hello!
> 
> Does Cygwin come with qemu packages?
> 
> Dan

why should an "Unix Emulation layer" that run in "User Space"
trying to run a "Full-system emulation" (https://www.qemu.org/) ?



It seems like using square wheels

Regards
Marco

Re: Qemu packages for Cygwin?

[Dan Shelton]

On Mon, 18 Dec 2023 at 07:54, Marco Atzeri via Cygwin <cygwin@cygwin.com> wrote:
>
> On 18/12/2023 07:42, Dan Shelton via Cygwin wrote:
> > Hello!
> >
> > Does Cygwin come with qemu packages?
> >
> > Dan
>
> why should an "Unix Emulation layer" that run in "User Space"
> trying to run a "Full-system emulation" (https://www.qemu.org/) ?
>
>
>
> It seems like using square wheels

Nope. The Qemu packages on LInux have a much more wider functionality,
and more features, compared to the TUSBTADI "The User Should Be
Treated As Dumb Idiot" versions on Windows. It absolutely makes sense.

Dan
-- 
Dan Shelton - Cluster Specialist Win/Lin/Bsd

Re: Qemu packages for Cygwin?

[Brian Inglis]

On 2023-12-18 00:14, Dan Shelton via Cygwin wrote:
> On Mon, 18 Dec 2023 at 07:54, Marco Atzeri via Cygwin wrote:
>> On 18/12/2023 07:42, Dan Shelton via Cygwin wrote:
>>> Does Cygwin come with qemu packages?

>> why should an "Unix Emulation layer" that run in "User Space"
>> trying to run a "Full-system emulation" (https://www.qemu.org/) ?
>> It seems like using square wheels

> Nope. The Qemu packages on LInux have a much more wider functionality,
> and more features, compared to the TUSBTADI "The User Should Be
> Treated As Dumb Idiot" versions on Windows. It absolutely makes sense.

Cygwin has trouble providing some POSIX features under Windows due to its API 
limitations, using "documented" Windows APIs, allowing it to run under ReactOS, 
Wine, and similar emulators, with which there is some interchange.

It does not provide or support much in the way of privileged Unix or Windows 
features or access, except for providing emulation for running daemons as 
services, and some caching of SAM, AD, and process info.

It is totally inadequate as a platform to provide or support any x86 
virtualization or even virtual machine management features, as it can not 
provide access to any machine features that do not have "documented" Windows APIs.
Look at the /proc filesystem emulation limitations for examples of where Windows 
lacks APIs to get information available under Linux.

You complain elsewhere about performance: can you imagine how bad it would be, 
compared to Hyper-V, WSL, VirtualBox, etc.

You can build native Windows Qemu under Cygwin using its native Windows Mingw64 
cross toolchain and libraries, as well as under native Windows Mingw64 and 
Msys2. These provide the best possible performance available under Windows.

The current all volunteer group lingers about the same numbers, with some 
experienced members leaving due to lack of time or interest, and some newer 
members joining and helping out more as they get experience, but they never 
really have enough spare free time to keep up with Windows and POSIX changes, 
address and/or fix issues, improve the emulation, improve POSIX compatibility, 
as well as support much in the way of new features.
-- 
Take care. Thanks, Brian Inglis              Calgary, Alberta, Canada

La perfection est atteinte                   Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter  not when there is no more to add
mais lorsqu'il n'y a plus rien à retirer     but when there is no more to cut
                                 -- Antoine de Saint-Exupéry

Re: Qemu packages for Cygwin?

[Cedric Blancher]

On Mon, 18 Dec 2023 at 18:33, Brian Inglis via Cygwin <cygwin@cygwin.com> wrote:
>
> On 2023-12-18 00:14, Dan Shelton via Cygwin wrote:
> > On Mon, 18 Dec 2023 at 07:54, Marco Atzeri via Cygwin wrote:
> >> On 18/12/2023 07:42, Dan Shelton via Cygwin wrote:
> >>> Does Cygwin come with qemu packages?
>
> >> why should an "Unix Emulation layer" that run in "User Space"
> >> trying to run a "Full-system emulation" (https://www.qemu.org/) ?
> >> It seems like using square wheels
>
> > Nope. The Qemu packages on LInux have a much more wider functionality,
> > and more features, compared to the TUSBTADI "The User Should Be
> > Treated As Dumb Idiot" versions on Windows. It absolutely makes sense.
>
> Cygwin has trouble providing some POSIX features under Windows due to its API
> limitations, using "documented" Windows APIs, allowing it to run under ReactOS,
> Wine, and similar emulators, with which there is some interchange.
>
> It does not provide or support much in the way of privileged Unix or Windows
> features or access, except for providing emulation for running daemons as
> services, and some caching of SAM, AD, and process info.
>
> It is totally inadequate as a platform to provide or support any x86
> virtualization or even virtual machine management features, as it can not
> provide access to any machine features that do not have "documented" Windows APIs.
> Look at the /proc filesystem emulation limitations for examples of where Windows
> lacks APIs to get information available under Linux.
>
> You complain elsewhere about performance:

I am also complaining about performance, but it is NOT "performance in
general": What really sucks is the filesystem inode operations and
file name lookup, e.g. /bin/find&friends are absurdly slow because of
the link emulation and the inflation of syscalls caused by it - just
up to five times more accesses just to handle filename, filename.lnk,
filename.lnk.exe, filename.lnk.bat etc
Other areas have adequate performance, e.g. read/write performance is OK

> can you imagine how bad it would be,
> compared to Hyper-V, WSL, VirtualBox, etc.

No, qemu is called the "quick emulator", and has more functionality
than just being a hypervisor, like being able to emulate ARM and SPARC
platforms. Even if the x86 hypervisor cannot be used, there is still
lots of functionality.

If there are bugs in the POSIX emulation layer, then those bugs should
be 1) documented and 2) fixed.
Also please do not shoot down package proposals out of the FEAR that
"something" might not work.

Ced
-- 
Cedric Blancher <cedric.blancher@gmail.com>
[https://plus.google.com/u/0/+CedricBlancher/]
Institute Pasteur

Re: Qemu packages for Cygwin?

[Brian Inglis]

On 2024-01-03 02:10, Cedric Blancher via Cygwin wrote:
> On Mon, 18 Dec 2023 at 18:33, Brian Inglis via Cygwin <cygwin@cygwin.com> wrote:
>>
>> On 2023-12-18 00:14, Dan Shelton via Cygwin wrote:
>>> On Mon, 18 Dec 2023 at 07:54, Marco Atzeri via Cygwin wrote:
>>>> On 18/12/2023 07:42, Dan Shelton via Cygwin wrote:
>>>>> Does Cygwin come with qemu packages?
>>
>>>> why should an "Unix Emulation layer" that run in "User Space"
>>>> trying to run a "Full-system emulation" (https://www.qemu.org/) ?
>>>> It seems like using square wheels
>>
>>> Nope. The Qemu packages on LInux have a much more wider functionality,
>>> and more features, compared to the TUSBTADI "The User Should Be
>>> Treated As Dumb Idiot" versions on Windows. It absolutely makes sense.
>>
>> Cygwin has trouble providing some POSIX features under Windows due to its API
>> limitations, using "documented" Windows APIs, allowing it to run under ReactOS,
>> Wine, and similar emulators, with which there is some interchange.
>>
>> It does not provide or support much in the way of privileged Unix or Windows
>> features or access, except for providing emulation for running daemons as
>> services, and some caching of SAM, AD, and process info.
>>
>> It is totally inadequate as a platform to provide or support any x86
>> virtualization or even virtual machine management features, as it can not
>> provide access to any machine features that do not have "documented" Windows APIs.
>> Look at the /proc filesystem emulation limitations for examples of where Windows
>> lacks APIs to get information available under Linux.
>>
>> You complain elsewhere about performance:
> 
> I am also complaining about performance, but it is NOT "performance in
> general": What really sucks is the filesystem inode operations and
> file name lookup, e.g. /bin/find&friends are absurdly slow because of
> the link emulation and the inflation of syscalls caused by it - just
> up to five times more accesses just to handle filename, filename.lnk,
> filename.lnk.exe, filename.lnk.bat etc
> Other areas have adequate performance, e.g. read/write performance is OK
> 
>> can you imagine how bad it would be,
>> compared to Hyper-V, WSL, VirtualBox, etc.
> 
> No, qemu is called the "quick emulator", and has more functionality
> than just being a hypervisor, like being able to emulate ARM and SPARC
> platforms. Even if the x86 hypervisor cannot be used, there is still
> lots of functionality.
> 
> If there are bugs in the POSIX emulation layer, then those bugs should
> be 1) documented and 2) fixed.

There are some functions that are not implemented because they can not be 
emulated under Windows, or require far too much work, or code and space in the dll.

> Also please do not shoot down package proposals out of the FEAR that
> "something" might not work.

Rather knowledge from experience that MS supports certain features in their own 
products e.g. WSL/2, Hyper-V and does not provide docs for some of their 
proprietary interfaces to allow others to do the same, without e.g. writing 
their own drivers to bypass Windows.

As long as you are happy porting a software emulator to build under cygport and 
run atop a POSIX layer, let us see how well you can do, by your own measures.

-- 
Take care. Thanks, Brian Inglis              Calgary, Alberta, Canada

La perfection est atteinte                   Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter  not when there is no more to add
mais lorsqu'il n'y a plus rien à retirer     but when there is no more to cut
                                 -- Antoine de Saint-Exupéry

Re: Qemu packages for Cygwin?

[matthew patton]

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On Wednesday, January 3, 2024 at 04:10:56 AM EST, Cedric Blancher via Cygwin <cygwin@cygwin.com> wrote:
 
> general": What really sucks is the filesystem inode operations and
> file name lookup, e.g. /bin/find&friends are absurdly slow because of
> the link emulation and the inflation of syscalls caused by it - just
...>If there are bugs in the POSIX emulation layer, then those bugs should> be 1) documented and 2) fixed.

I think we look forward to your patches and rework to minimize all those link traversals. Maybe a CYGWIN env value that turns off all that legacy stuff? I'd welcome that - and replacing the default 'link' to be 'mklink' links instead of Junctions which some Windows programs do NOT like and fail.
For everything else there is WSL. Seriously. Cygwin has an incredible amount of coverage, but it could be pared down to 20 packages and I'd be perfectly happy. 

  

Re: Qemu packages for Cygwin?

[Richard Campbell]

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On Wed, Jan 3, 2024 at 12:42 PM matthew patton via Cygwin <cygwin@cygwin.com>
wrote:

> Cygwin has an incredible amount of coverage, but it could be pared down to
> 20 packages and I'd be perfectly happy.
>

I suspect most people are in this same position, except that they each have
a different list of 20 packages.

Best regards,

-Richard Campbell.