Re: Hard 64 bit. Will 32 bit still run in a VM?

From	Barry Margolin <barmar@alum.mit.edu>
Newsgroups	comp.sys.mac.system
Subject	Re: Hard 64 bit. Will 32 bit still run in a VM?
Date	2018-05-27 22:35 -0400
Organization	A noiseless patient Spider
Message-ID	<barmar-87133C.22354027052018@reader.eternal-september.org> (permalink)
References	<RGmOC.244790$1e7.184719@fx38.iad> <pefbs0$9h6$1@gioia.aioe.org> <YYGOC.252459$DS3.225190@fx42.iad> <pefp2i$rdh$1@gioia.aioe.org> <0001HW.20BBA085022597F87000048742CF@news.supernews.com>

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In article <0001HW.20BBA085022597F87000048742CF@news.supernews.com>,
 Wolffan <akwolffan@gmail.com> wrote:

> On 27 May 2018, Your Name wrote
> (in article <pefp2i$rdh$1@gioia.aioe.org>):
> 
> > On 2018-05-27 23:13:59 +0000, JF Mezei said:
> > > On 2018-05-27 18:35, Your Name wrote:
> > > >
> > > > As long as the emulator itself is programmed to run as 64-bit, what
> > > > runs on it is irrelevant to MacOS 10.14 and later.
> > >
> > > Whether emulated or not (Fusion lets Windows runs native without
> > > translation, but intercepts certain operations).
> > >
> > > The question to me is whether when Fusion intercepts a 32 bit operation,
> > > if it passes it to the equivalent 32 bit OS-X API or whether it converts
> > > this to 64 bit APIs and 64 bit addresses. (and there would be some
> > > fancy virtual memory footwork involved).
> > >
> > > This will dictate what happens when Apple pulls 32 bit APIs out.
> >
> > Technically Parallels and VMWare aren't emulators - they're
> > virtualisation apps, but a similar stance applies. What may happen is
> > that the developers simply change their "recommended" options to no
> > longer allow older non-64-bit OSes. It really depends on how difficult
> > it is for them to continue to support old OSes and whether there are
> > enough users of old OSes to warrant that effort.
> >
> > In some cases is might require changing from a virtulisation app to an
> > emulation app (i.e. one that does do on-the-fly translation of
> > everything), which may mean a drop in performance.
> 
> I remember Virtual PC. Emulation is gonna mean a _massive_ drop in 
> performance unless the devs are very, very, VERY good. And no-body’s _that_ 
> good.

The things that affect whether an *Operating System* supports 32-bit or 
64-bit mode are generally the data structures used in system calls. 
There isn't generally an issue with the execution of ordinary 
instructions that don't call into the kernel.

So when you're running another operating system under virtualization, 
the word size that matters is what the guest OS supports. I don't think 
any emulation should generally be necessary.

Of course, the virtualization software sometimes has to trap operations 
and pass them on to the host OS. As long as the virtualization software 
is 64-bit, it should continue to work.

-- 
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***

Thread

Hard 64 bit. Will 32 bit still run in a VM? Alan Browne <bitbucket@blackhole.com> - 2018-05-26 11:22 -0400
  Re: Hard 64 bit. Will 32 bit still run in a VM? JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-05-26 20:09 -0400
    Re: Hard 64 bit. Will 32 bit still run in a VM? Alan Browne <bitbucket@blackhole.com> - 2018-05-27 11:29 -0400
      Re: Hard 64 bit. Will 32 bit still run in a VM? android <here@there.was> - 2018-05-27 18:03 +0200
        Re: Hard 64 bit. Will 32 bit still run in a VM? Your Name <YourName@YourISP.com> - 2018-05-28 10:35 +1200
          Re: Hard 64 bit. Will 32 bit still run in a VM? nospam <nospam@nospam.invalid> - 2018-05-27 18:57 -0400
          Re: Hard 64 bit. Will 32 bit still run in a VM? JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-05-27 19:13 -0400
            Re: Hard 64 bit. Will 32 bit still run in a VM? Your Name <YourName@YourISP.com> - 2018-05-28 14:21 +1200
              Re: Hard 64 bit. Will 32 bit still run in a VM? Wolffan <akwolffan@gmail.com> - 2018-05-27 22:27 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? nospam <nospam@nospam.invalid> - 2018-05-27 22:35 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? Steve Carroll <frelwizzen@gmail.com> - 2018-05-27 20:52 -0700
                Re: Hard 64 bit. Will 32 bit still run in a VM? JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-05-28 18:33 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? Barry Margolin <barmar@alum.mit.edu> - 2018-05-27 22:35 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? Alan Browne <bitbucket@blackhole.com> - 2018-05-31 08:49 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? "Snit's dysautonomia http://bit.ly/2Jqpplk" <frelwizzen@gmail.com> - 2018-06-03 04:41 -0700
                Re: Hard 64 bit. Will 32 bit still run in a VM? "Snit's dysautonomia http://bit.ly/2Jqpplk" <frelwizzen@gmail.com> - 2018-06-03 08:20 -0700
                Re: Hard 64 bit. Will 32 bit still run in a VM? Your Name <YourName@YourISP.com> - 2018-05-28 19:30 +1200
                Re: Hard 64 bit. Will 32 bit still run in a VM? Steve Carroll <frelwizzen@gmail.com> - 2018-05-28 05:39 -0700
                Re: Hard 64 bit. Will 32 bit still run in a VM? nospam <nospam@nospam.invalid> - 2018-05-28 09:05 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? Steve Carroll <frelwizzen@gmail.com> - 2018-05-28 07:29 -0700
                Re: Hard 64 bit. Will 32 bit still run in a VM? JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-05-28 18:28 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? Steve Carroll <frelwizzen@gmail.com> - 2018-05-28 21:03 -0700
                Re: Hard 64 bit. Will 32 bit still run in a VM? Alan Browne <bitbucket@blackhole.com> - 2018-05-31 08:50 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? Alan Browne <bitbucket@blackhole.com> - 2018-05-31 08:47 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? nospam <nospam@nospam.invalid> - 2018-05-31 10:55 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? Alan Browne <bitbucket@blackhole.com> - 2018-05-31 14:03 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? nospam <nospam@nospam.invalid> - 2018-05-31 15:57 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? android <here@there.was> - 2018-06-01 06:16 +0000
                Re: Hard 64 bit. Will 32 bit still run in a VM? nospam <nospam@nospam.invalid> - 2018-06-01 03:01 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? android <here@there.was> - 2018-06-01 08:17 +0000
                Re: Hard 64 bit. Will 32 bit still run in a VM? Jolly Roger <jollyroger@pobox.com> - 2018-06-01 15:53 +0000
                Re: Hard 64 bit. Will 32 bit still run in a VM? nospam <nospam@nospam.invalid> - 2018-06-01 12:51 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? "Auric__" <not.my.real@email.address> - 2018-06-01 17:23 +0000
                Re: Hard 64 bit. Will 32 bit still run in a VM? nospam <nospam@nospam.invalid> - 2018-06-01 14:11 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-01 14:26 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? nospam <nospam@nospam.invalid> - 2018-06-01 14:35 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-01 17:29 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? Jolly Roger <jollyroger@pobox.com> - 2018-06-02 15:58 +0000
                Re: Hard 64 bit. Will 32 bit still run in a VM? ANTant@zimage.com (Ant) - 2018-06-02 11:37 -0500
                Re: Hard 64 bit. Will 32 bit still run in a VM? Your Name <YourName@YourISP.com> - 2018-06-03 12:13 +1200
                Re: Hard 64 bit. Will 32 bit still run in a VM? "Snit's dysautonomia http://bit.ly/2Jqpplk" <frelwizzen@gmail.com> - 2018-06-03 05:59 -0700
                Re: Hard 64 bit. Will 32 bit still run in a VM? ANTant@zimage.com (Ant) - 2018-06-03 23:10 -0500
                Re: Hard 64 bit. Will 32 bit still run in a VM? Your Name <YourName@YourISP.com> - 2018-06-04 19:22 +1200
                Re: Hard 64 bit. Will 32 bit still run in a VM? ANTant@zimage.com (Ant) - 2018-06-05 03:39 -0500
                Re: Hard 64 bit. Will 32 bit still run in a VM? Your Name <YourName@YourISP.com> - 2018-06-06 09:29 +1200
                Re: Hard 64 bit. Will 32 bit still run in a VM? Steve Carroll <frelwizzen@gmail.com> - 2018-06-04 02:49 -0700
                Re: Hard 64 bit. Will 32 bit still run in a VM? Steve Carroll <frelwizzen@gmail.com> - 2018-06-04 07:16 -0700
                Re: Hard 64 bit. Will 32 bit still run in a VM? Lewis <g.kreme@gmail.com.dontsendmecopies> - 2018-06-02 01:37 +0000
                Re: Hard 64 bit. Will 32 bit still run in a VM? JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-02 01:29 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? Your Name <YourName@YourISP.com> - 2018-06-02 19:10 +1200
                Re: Hard 64 bit. Will 32 bit still run in a VM? dempson@actrix.gen.nz (David Empson) - 2018-06-02 23:32 +1200
                Re: Hard 64 bit. Will 32 bit still run in a VM? nospam <nospam@nospam.invalid> - 2018-06-02 09:03 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-02 14:34 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? nospam <nospam@nospam.invalid> - 2018-06-02 14:35 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? Lewis <g.kreme@gmail.com.dontsendmecopies> - 2018-06-02 14:31 +0000
                Re: Hard 64 bit. Will 32 bit still run in a VM? Jolly Roger <jollyroger@pobox.com> - 2018-06-02 15:49 +0000
                Re: Hard 64 bit. Will 32 bit still run in a VM? JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-01 14:23 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? nospam <nospam@nospam.invalid> - 2018-06-01 14:35 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? Alan Browne <bitbucket@blackhole.com> - 2018-06-02 13:47 -0400
                Re: Hard 64 bit. Will 32 bit still run in a VM? Lewis <g.kreme@gmail.com.dontsendmecopies> - 2018-06-05 09:16 +0000
          Re: Hard 64 bit. Will 32 bit still run in a VM? Alan Browne <bitbucket@blackhole.com> - 2018-05-31 08:46 -0400
        Re: Hard 64 bit. Will 32 bit still run in a VM? Steve Carroll <frelwizzen@gmail.com> - 2018-05-27 16:31 -0700
          Re: Hard 64 bit. Will 32 bit still run in a VM? android <here@there.was> - 2018-05-28 06:52 +0200
            Re: Hard 64 bit. Will 32 bit still run in a VM? Steve Carroll <frelwizzen@gmail.com> - 2018-05-27 22:09 -0700

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