DOS programs under "screen"

[Barry Kelly]

Andrew Schulman wrote:

> > In general, non-cygwin programs can't be run reliably inside of an
> > application that uses cygwin PTYs, including xterm, rxvt, and screen.
> 
> Maybe someone knows a solution to this, but I don't.  Although I maintain screen
> for Cygwin, I know almost nothing of the details of how terminals work.  I could
> imagine some kind of a DOS-to-Unix terminal wrapper program, but I've never seen
> one and have no idea how it would work.

Windows implements console mode as a client-server protocol between the
executable (ntvdm.exe for DOS apps) and winsrv.dll (hosted in
csrss.exe), but the protocol isn't easily hookable. I guess one would
have to hijack the console APIs, perhaps by stepping into the
application using debugging APIs and overwriting the DLL imports, but it
would be pretty painful.

I don't know how DOS programs that use graphics modes (in fullscreen)
are implemented, though these must be rare now given that Vista no
longer has a full-screen mode.

-- Barry

-- 
http://barrkel.blogspot.com/

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