Mail Archives: djgpp/2009/01/12/09:00:38
Hi,
On Jan 12, 2:10 am, Jim Michaels <jmich DOT DOT DOT AT yahoo DOT com> wrote:
>
> My best understanding is that Windows 64-bit OS's do not come with
> command.com. instead they come with cmd.exe, a 32-bit or 64-bit
> native shell.
The COMMAND.COM that modern Windows use (e.g. XP) is from Windows ME.
> If you want to run MS-DOS applicaitons, you are out of
> luck on 64-bit versions of the OS.
AMD64 doesn't support 16-bit, so unless MS wants a cpu emulator a la
DOSBox or just to somehow emulate the 16-bit stuff, it won't work. I
wish they would, but NTVDM is deprecated, so they don't really care
anymore.
> try buying a 32-bit OS if you
> intend to do development or run MS-DOS applications. I am not sure,
> but I think Vista 32-bit *may* come with command.com - ask a friend
> who has it or ask someone on the 'net.
Yes, Vista 32-bit (which I'm running now, which is forced on everybody
these days) runs some DOS stuff, just not as much as XP and not as
stable. And since it's the same kernel as 2k3 or Win7, that doesn't
bode well for the future.
> Another possiblity to run DOS applications that was suggested is
> VMWARE or other VM (Virtual Machine) software that can run FreeDOS.
The problem is that V86 mode (which AMD64 lacks) is fast unlike full
emulation (DOSBox or BOCHS), which can be pretty slow. I've found QEMU
slower than VirtualBox, but at least the former allows "fat:/mydir/
mysub" access to host files (but not write). In short, even if it's
fast enough, compatible enough, or "free" enough, it might have file
sharing issues. And you need more and more RAM, which is why some
people are moving to x86-64 in the first place. (FreeBSD among others
supports PAE, not sure why that isn't more popular. Maybe driver
incompatibility, I dunno.)
http://en.wikipedia.org/wiki/Physical_Address_Extension
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