Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!sun-barr!newstop!sun!imagen!qmsseq!pipkins
From: pipkins@qmsseq.imagen.com (Jeff Pipkins)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Dos Func. 4B emulation
Message-ID: <93@qmsseq.imagen.com>
Date: 23 Jan 90 18:32:08 GMT
References: <844@ocsmd.ocs.com>
Reply-To: pipkins@qmsseq.UUCP (Jeff Pipkins)
Organization: QMS Inc., Mobile, Alabama
Lines: 25

In article <844@ocsmd.ocs.com> motti@ocsmd.ocs.com (Motti Bazar) writes:
>I'm developing a DOS shell that plays with Interrupt 21H.
>One function (4B - Exec) is a tough one to emulate. Is there
>anybody that knows about any public domain code to emulete this
>function ??? If there is interest, I'll post the answer.

Don't let it intimidate you; it's not as difficult as it may first appear.
I've written such a function, but I'm unable to send it to you since it
belongs to my employer now.  But here are some hints:

First, get a copy of the DOS technical reference guide.  It documents the
format of the .EXE header and tells how it is loaded.  The MS-DOS encyclo-
pedia is recommended and probably also has this info.

There is an operating system called Wendin-DOS that comes with source
code (for about $100) that contains an .EXE loader, but of course, that
belongs to Wendin...

BEST BET: I noticed several progams on SIMTEL that were replacements for
the DOS EXE2BIN program.  Such a program is almost identical to an .EXE
loader.

Hope this helps.
-Jeff
pipkins@imagen.com