Path: utzoo!mnetor!uunet!husc6!ncar!oddjob!gargoyle!ddsw1!karl
From: karl@ddsw1.UUCP (Karl Denninger)
Newsgroups: comp.unix.microport
Subject: Re: uPort 386
Message-ID: <871@ddsw1.UUCP>
Date: 16 Mar 88 15:27:10 GMT
References: <929@xn.LL.MIT.EDU> <7602@agate.BERKELEY.EDU> <3679@killer.UUCP>
Reply-To: karl@ddsw1.UUCP (Karl Denninger)
Organization: Macro Computer Solutions, Inc., Mundelein, IL
Lines: 53
Summary: Load the '286 devsys in a chrooted area.

In article <3679@killer.UUCP> wnp@killer.UUCP (Wolf Paul) writes:
$In article <7602@agate.BERKELEY.EDU> ewv@violet.berkeley.edu (Eric Varsanyi) writes:
$>In article <929@xn.LL.MIT.EDU> singer@XN.LL.MIT.EDU (Matthew R. Singer) writes:
$>>1)  Can the 386 system compile for a 286 machine (Large model)?
$>No, the supplied compiler cannot produces 286 executables. The system does
$>seem to be able to run COFF 286 executables.

WARNING: These '286 executables must be READABLE to execute, not just
executable.  Scratch any idea of security for your compiled modules.

$>>    If not, since I need the system for product development,
$>>    can V/AT and V/386 reside on the same machine?
$>I've heard gripes here that people cannot get the 286 product up on a 386,
$>theoretically it should work, the 386 is downward compatible.

The '286 product runs on our '386 systems as does the '386 product (we sell
Televideo).

$Well, if the 386 compiler will not compile 286 code, but the 386 UNIX will run
$286 COFF binaries, you might be able to run the 286 Development System under
$your 386 UNIX kernel. Of course you'd have to use not only the 286 compiler,
$assembler & linker, but the 286 libraries and include files as well.
$
$It should even be possible to set up a shell script which does a "chroot"
$to a separate "286 directory hierarchy" to automatically access a
$286-specific /usr/lib/, /usr/include/, etc.

This works... we use it here for cross-development.

The 'installit' program on the '386 can and will read '286 format installit
disks; this is how we finally got '286 compilation capability on our
Microport/386 system.

Just don't forget that you need the shared libraries in the chrooted area,
or nothing will work at all! :-)

Two notes about this:
	1) '286 SDB will not work on the 386 runtime.  Thus you cannot DEBUG
	   80286 code on the '386 (yuck!), for this, you need a '286 as well.
	   Core dumps in a '286 COFF binary are a *bitch* to find without a
	   workable debugger!
	2) The 'chrooted' area must have all the directories and files which
	   are normally required for operation.  If you put your chrooted
	   area on the same filesystem as your primary operating files, you
	   can at least use 'ln' and save significant amounts of space.

This requires that you have both licenses, too -- which makes quite a dent
in the pocketbook.....

------
Karl Denninger		       |  Data: +1 312 566-8912
Macro Computer Solutions, Inc. | Voice: +1 312 566-8910
...ihnp4!ddsw1!karl	       | "Quality solutions for work or play"