python 2.7.12 on Linux behaving differently than on Windows

Random832 random832 at fastmail.com
Tue Dec 6 10:05:57 EST 2016


On Tue, Dec 6, 2016, at 02:01, Larry Hudson via Python-list wrote:
> On 12/05/2016 06:51 PM, Nathan Ernst wrote:
> > IIRC, command.com was a relic of Win9x running on top of DOS and was a
> > 16-bit executable, so inherently crippled (and probably never support by
> > the NT kernel). Whereby cmd.exe coexisted but ran in a 32-bit context.
> 
> I know my 79-year-old memory is definitely subject to "senior moments"
> and not too reliable, but 
> IIRC it was Windows prior to 9x (Win 3 and earlier) that were 16 bit and
> ran on top of DOS. 
> Win95 was the first 32 bit version and was independent from DOS.

Yes but there was no* 32-bit windows command interpreter - it ran DOS in
a virtual machine inside it. Windows 3 did the same, actually - the real
architecture of Windows/386 was a 32-bit protected mode host kernel
called VMM32.VXD that ran all of Windows in one virtual machine and each
DOS window in another one, leading to the odd consequence of there being
cooperative multitasking between Windows apps but pre-emptive
multitasking between DOS apps [and between them and Windows].

The fact that Windows was launched at boot by running "win.com" (either
in autoexec.bat or manually at the command line) created a *perception*
that windows ran "on top of DOS", but running it really *replaced* DOS
in memory, putting the CPU into protected mode and everything. The
ability to boot into (or exit to) DOS was because people still did real
work (and games) in DOS and the virtual environment of DOS-on-Windows
didn't perform well enough to be sufficient.

*Well, I vaguely remember a version of cmd.exe that would run on Windows
98 floating around back in the day, but it certainly didn't come with
the OS. It might have been a pirated Windows NT component.


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