Path: utzoo!telly!attcan!uunet!odi!ed
From: ed@odi.com (Ed Schwalenberg)
Newsgroups: comp.windows.ms
Subject: Re: QEMM, Windows, and Winfract
Message-ID: <1990Oct24.144154.27665@odi.com>
Date: 24 Oct 90 14:41:54 GMT
References: <568@nih-csl.nih.gov>
Organization: Object Design, Inc.
Lines: 20
In-Reply-To: bert@helix.nih.gov's message of 23 Oct 90 23:10:50 GMT

In article <568@nih-csl.nih.gov> bert@helix.nih.gov (Bert Tyler) writes:

  Of course,
  given that a WinApp running in protected mode isn't supposed to be
  *able* to fling you out of Windows and back into DOS, I suppose that
  you are looking at some sort of co-operative effort in the bug
  department <grin>.

It depends on what you mean by "isn't supposed to."  Since all Windows
applications share a common address space, it's possible (and quite probable)
that a wild pointer can clobber any other application, including the kernel
routines themselves.  Less probable, but still possible, a protected-mode
application can modify any memory location, by modifying system data
structures like the LDT, which are not protected from application access.
So a buggy or malicious program can do anything it pleases, such as crashing
Windows, DOS, or locking up your machine.

Operating systems are "supposed to" prohibit applications from clobbering
one another.  Windows 3.0 doesn't try very hard.  There are strong hints in
the SDK and DDK documentation that future releases will try harder, though.