It's never going to be full speed nor perfect emulation. It's too
> tricky to emulate everything (esp. pmode). Anything to do with
> segmentation is probably lower priority (due to complexity and
> deprecation) than the bare minimum (686-ish pmode) that *nix and
> Windows require.

I'm aware an application running on FreeDOS inside of VirtualBox has to be
much slower.  That said, understand the future of most legacy operating
systems that ran on older hardware will be inside virtual machines.  I see
that as making FreeDOS and DOS applications immortal.  Moving to the Cloud
will make applications running on FreeDOS available on smartphones if they
aren't already.

Therefore getting to know these virtual products inside computers and in
the Cloud will be a good idea.

> I know I sound like a broken record, but having VT-X enabled (if
> possible, esp. nested page tables or whatever) is the only best setup
> I know of.

I'll see if that isn't already set to on, A.K.A "enabled". (An anti-jargon
statement :-)

> Probably best to try some (official or unofficial) benchmark, e.g.
> Dhrystone, doom -timedemo demo3 (for 1.9 shareware), or just timing
> some random cmdline program (runtime ..., esp. archiver or compressor)
> or DJGPP compile of something (redir -t gcc ...).
> I guess it depends on what you're trying to test (FPU, gfx, etc).

Since M$-Windozes 7 seems to resist DOS program setup, I can't benchmark
them outside VirtualBox.  The programs I have are all character based
display, that is not using bit-mapped graphics. Usually some compiled dbase
program with 10 to 20 open files.

> > Second, what steps should be taken to walk through application
> performance
> > issues within FreeDOS?  Is there a sequence that would narrow issues to
> > solutions?
> Not that I know of. You'd have to debug VirtualBox itself (or maybe it
> can optionally have a built-in debugger like some other emulators??
> dunno ...).
> Most of the issues are x86 emulation, then BIOS, then peripherals
> (mouse, keyboard, CD, etc).

Then for VirtualBox the test is the x86 machine level emulation.  How does
FreeDOS perform directly on hardware vs how it performs inside VirtualBox.

The other obvious test is how FreeDOS performs on the likes of Amazon's

John S Wolter
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