From: joel@wam.umd.edu (Joel M. Hoffman) Subject: Re: inb/outb babble.. was Re: Problem with inb and outb.. Date: Mon, 15 Jun 1992 12:55:04 GMT
In article <y8fl6kk@lynx.unm.edu> techs@pioneer.unm.edu (Erik Fichtner) writes:
>In article <1992Jun14.102604.11229@uniwa.uwa.edu.au> oreillym@tartarus.uwa.edu.au (Michael O'Reilly) writes:
>>techs@pioneer.unm.edu (Erik Fichtner) writes:
>>: Well, Here I am working on the dos emulator.... more things
>>: What's wrong here??!
>>
>>User programs CAN'T do arbitrary I/O to ports. You have to go via the
>>ioperm sys call to explicity allow it. In general you shouldn\'t need to
>>go to the ports as linux can get very confused if you do. Allowing the
>>dos emulator to do all the port I/O it wants is almost guarenteed to
>>crash linux.. ;)
>>
>Heheh.. Yes, a friend and I realize that this will probably defeat the
>purpose of Linux, but we're stubborn. I want it to run WWIV. that's
>the only program I have any need of from DOS. also need Turbo C to keep
>WWIV happy. these programs both requre heavy port io. anyway, this
>is the end goal I'm working towards. for ports that really destroy Linux,
If it's not too hard, I would suggest two compile-time options, one
with direct port access by the vm86 process, and the other with
emulation. Emulation is a MUCH better solution for many reasons. One
that comes to mind is that more than one vm86 process can run at a
time. The other, already stated, is that it won't compromise system
integr{ty.
>My friends's goal is to hack the kernel to allow switching between graphics
>consoles so that he can run X on one console and GeoWorks under the dos
>emulator. ;-) It'll be a cool hack if it works. so will the port stuff,
>i think.
CMU's Dos emulator has code for completely saving and restoring the
state of the VGA card. You might want to look at it.
-Joel