[alt.msdos.programmer] Use of DOS "Load but don't execute" call

trier@cwlim.CWRU.EDU (Stephen C. Trier) (07/11/90)

I need a way to copy-protect programs with internal overlays under Novell
Netware.  The NetWare execute-only bit fails on these programs because they
need to read the .EXE file after startup in order to retrieve their overlay
sections.  In the course of looking for a valid technique, I came across
int 21h, function 4Bh, which is the MS-DOS EXEC call.

The call itself was not surprising; I've always known it was there.  What
was surprising was the undocumented subfunction 01, which I found in Ralf
Brown's Interrupt List.  Subfunction 01 is labeled "Load but don't execute"
and is marked as internal, but lacks any information on its use.

My question is whether anyone can tell me more about this function.  Is it
called by subfunction 00, "Load and execute"?  Has anyone made use of function
01h in their programming?

-- 
Stephen Trier                              Case Western Reserve University
Home: sct%seldon@scl.cwru.edu              Information Network Services
Work: trier@cwlim.ins.cwru.edu
                 I do _not_ speak for the University.