Hi all..

i read in the FAQ's that MS_DOS is dead...but Dos is not..

What dos comes with XP.....

or should I be downloading something New


John

Wikipedia says NTVDM runs a mod'ed DOS 5 http://en.wikipedia.org/wiki/DOS#With_Microsoft_Windows

If you want to use a DOS-like OS for some reason, FreeDOS is probably the most up to date one you'll find. Dex4u has a toy OS named miniDOS that is supposed to mimic DOS and it's APIs. You could run either in Bochs.

Hi..

Thanks for that.......now..If I wanted to put freeDOS in an old win95 computer....what effect would that have to the computer..

Depends, I don't know if the FreeDOS installer can partition disks, so about the worst that could happen is that it could format the hdd without asking first, or it could blow up... whichever happens first...

You should probably try it in a VM before installing it though. There plenty of good, free virtual machines, Bochs is used a lot by OSdev'ers, but is suitable for real use too.

The worst possibility, sorry for the crappy ad, it's worth it though.

> What dos comes with XP.....

None at all (there is NTVDM ...)

> or should I be downloading something New

* If you want to develop for DOS, get DOS

* If you want to develop for something else, get that one (and use appropriate subforum)

> wanted to put freeDOS in an old win95 computer....what
> effect would that have to the computer..

None at all (waste 0.3 to 300 MiB of HD space).

Be warned that FreeDOS distros are obsolete and the installer isn't good, also the 2039 kernel has a bad regression. If you want to get FreeDOS, download kernel 2038 and latest versions of the other stuff, and install manually. You can drop FreeDOS instead or besides Windaube 95/98/ME, use the METAKERN thing to multiboot

> http://www.metacafe.com/watch/1022826/exploding_computer/ The worst possibility, sorry for the crappy ad, it's worth it though.

B.S. (entirely black screen)

Hi all

Tell me if I am totally wrong here....but does DOS work better as such when wanting to talk to the real world.
My question resulted from not being able to run a piece of code, given on another part of the forum to get the CPU frequency.... would not work on my old Toshiba Satellite 220CDS laptop...I think the conclusion was that its not seeing the rdtsc instruction.....From my reading, which at time can be a dangerous thing....the rdtsc came out of being protected to being able to be used in programs in pentium with mmx of similar....which I dont think mine is.....so as it does have a TSC it seems it cant be read...

Is there any way to change this......I Think it is CR4 that has a bit that controls this.

> was that its not seeing the rdtsc instruction.
> I Think it is CR4 that has a bit that controls this.

YES, but AFAIK neither Windaube nor Linux do set it, and even worse, in DOS you have real mode so this bit is irrelevant and RDTSC will work if present (Pentium, maybe late 80486's too).

Maybe in V86 mode RDTSC will not work on late 80486's or early Pentium's, that's why FreeDOS EMM386 and JEMM386 do "emulate" this instruction.