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Re: Misremembered

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On Ma, 15 feb 22, 12:41:28, John Hasler wrote:
>  Andrei POPESCU writes:
> > When it loads a kernel or chain-loads another boot-loader it basically
> > hands over control completely,
> 
> Which is what DOS does.

That was possibly not the best choice of words from my side.

DOS was both very limited in capabilities and didn't implement any kind 
of access control or similar. Each application could basically take full 
control over the hardware[1], and any slightly advanced application did, 
because DOS didn't provide much for them to use[2].

But at any point the *same* instance of DOS was still in the RAM, and 
when exiting the application one would typically be back to the *same* 
DOS shell from where the application was started (unless it all crashed, 
of course).

When GRUB is chain-loading another boot-loader or loads an OS it's also 
being completely evicted from RAM. The only way I can think of to "go 
back" without rebooting is for another boot-loader to chain-load the 
"initial" GRUB (which is a new instance of GRUB and in practice is not 
much different then rebooting).

[1] This was probably the best breeding ground for computer viruses the 
bad guys could ever hope for, as they could "infect" (append themselves 
to) any file on the system and install themselves in the MBR.

[2] Apparently this also made applications much harder to port to other 
OSes, which in practice worked as a sort of platform lock-in.

Hope this explains,
Andrei
-- 
http://wiki.debian.org/FAQsFromDebianUser

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Stupid question Hans <hans.ullrich@loop.de> - 2022-02-12 10:10 +0100
  Re: Stupid question harryweaver@tutanota.com - 2022-02-12 11:40 +0100
  Re: Stupid question rhkramer@gmail.com - 2022-02-12 15:10 +0100
    Misremembered (was: Re: Stupid question) rhkramer@gmail.com - 2022-02-14 16:10 +0100
      Re: Misremembered (was: Re: Stupid question) Bijan Soleymani <bijan@psq.com> - 2022-02-14 16:20 +0100
        Re: Misremembered (was: Re: Stupid question) David Wright <deblis@lionunicorn.co.uk> - 2022-02-15 00:30 +0100
          Re: Misremembered (was: Re: Stupid question) David <bouncingcats@gmail.com> - 2022-02-15 02:30 +0100
            Re: Misremembered (was: Re: Stupid question) Curt <curty@free.fr> - 2022-02-15 12:40 +0100
          Re: Misremembered (was: Re: Stupid question) Andrei POPESCU <andreimpopescu@gmail.com> - 2022-02-15 19:30 +0100
            Re: Misremembered John Hasler <john@sugarbit.com> - 2022-02-15 19:50 +0100
              Re: Misremembered Andrei POPESCU <andreimpopescu@gmail.com> - 2022-02-15 20:20 +0100
                Re: Misremembered John Hasler <john@sugarbit.com> - 2022-02-15 21:50 +0100
                Re: Misremembered Emanuel Berg <moasenwood@zoho.eu> - 2022-02-16 00:10 +0100
                Re: Misremembered Stefan Monnier <monnier@iro.umontreal.ca> - 2022-02-16 00:10 +0100
                Re: Misremembered gene heskett <gheskett@shentel.net> - 2022-02-16 00:50 +0100
                Re: Misremembered "Andrew M.A. Cater" <amacater@einval.com> - 2022-02-16 10:50 +0100
                Re: Misremembered Cindy Sue Causey <butterflybytes@gmail.com> - 2022-02-16 11:40 +0100
            Re: Misremembered Stefan Monnier <monnier@iro.umontreal.ca> - 2022-02-15 20:40 +0100
            Re: Misremembered (was: Re: Stupid question) David Wright <deblis@lionunicorn.co.uk> - 2022-02-16 21:40 +0100
  Re: Stupid question David Christensen <dpchrist@holgerdanske.com> - 2022-02-12 19:30 +0100
  Re: Stupid question Chuck Zmudzinski <brchuckz@netscape.net> - 2022-02-13 08:50 +0100
    Re: Stupid question Andrei POPESCU <andreimpopescu@gmail.com> - 2022-02-13 17:30 +0100
      Re: Stupid question "Thomas Schmitt" <scdbackup@gmx.net> - 2022-02-13 18:30 +0100
      Re: Stupid question Andrei POPESCU <andreimpopescu@gmail.com> - 2022-02-14 22:00 +0100
        Re: Stupid question David <bouncingcats@gmail.com> - 2022-02-15 02:10 +0100
          Re: Stupid question Andrei POPESCU <andreimpopescu@gmail.com> - 2022-02-15 19:40 +0100
      Re: Booting with Grub, was Re: Stupid question David Wright <deblis@lionunicorn.co.uk> - 2022-02-15 00:20 +0100
  Re: dual booting, was Re: Stupid question David Wright <deblis@lionunicorn.co.uk> - 2022-02-13 18:10 +0100
    Re: dual booting, was Re: Stupid question Hans <hans.ullrich@loop.de> - 2022-02-13 19:00 +0100
      Re: dual booting, was Re: Stupid question David Wright <deblis@lionunicorn.co.uk> - 2022-02-15 17:20 +0100
    Re: dual booting, was Re: Stupid question Andrei POPESCU <andreimpopescu@gmail.com> - 2022-02-13 19:30 +0100
      Re: dual booting, was Re: Stupid question David <bouncingcats@gmail.com> - 2022-02-14 00:20 +0100
        Re: dual booting, was Re: Stupid question David Wright <deblis@lionunicorn.co.uk> - 2022-02-15 17:20 +0100
      Re: dual booting, was Re: Stupid question David Wright <deblis@lionunicorn.co.uk> - 2022-02-15 17:20 +0100

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