Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!olivea!mintaka!spdcc!rbraun
From: rbraun@spdcc.COM (Rich Braun)
Newsgroups: comp.unix.sysv386
Subject: Re: DOS cross-development under SCO Unix?
Message-ID: <7004@spdcc.SPDCC.COM>
Date: 21 Mar 91 18:48:23 GMT
Organization: Kronos Inc., Waltham, Mass.
Lines: 30

bill@camco.Celestial.COM (Bill Campbell) writes:
>I am not real familiar with ``DOS extenders'' are these something
>like Hamburger Helper?

Heh heh, I suppose so.  I just got a piece of junk mail which reminded
me of the Unix/DOS wars.  It starts out "The NRA has 3 million members.
The HRCF has 30,000 members.  Does this mean 100 times as many people
are willing to fight for their right to own rifles as are willing to
fight for gay rights?"

The numbers are about 10 times higher for DOS and Unix:  there are
something like 30 million DOS systems in the world and probably under
1 million Unices.  But like the NRA, DOS isn't going away.  Hence the
invention of the DOS extender.

I'm not sure what all the DOS extender products look like, but ideally
they'd allow you to compile a program using 386 object code (rather than
8088) and a nonsegmented 32-bit (4 gigabyte) address space.  The system
interface to DOS then has to put parameters into the 640K low-memory
space and switch the processor into 8088 compatibility mode every time
you make a system call.

A number of compiler companies and others are creating these kinds of
products.  Xenix and Unix systems running on a 386 often provide
cross-compilation support (as compared, say, to using a DOS-native
product under a DOS emulator like VP/ix or Merge), but I don't know of
any which provide the extended address space characteristics needed to
port practically any large program to DOS.

-rich