[comp.unix.msdos] Dos App. Needs More Memory!!

wengland@stephsf.stephsf.com (Bill England) (09/12/90)

  I'm running a ravenously memory hungry Database Application under ODT-DOS.
  (Merge)  Whats worse is the programs taste in memory is exclusively for
  the extended flavor :-). 

  While Merge allows allocation of 'simulated' expanded memory I could not 
  find any provision for allocating extended memory.  On further thought
  it seems like a difficult proposition to create this feature under
  Unix.   Perhaps I'm overlooking something ... ?

  Comments?

 +--------
 |  Bill England
 |  Stephen Software Systems, Inc.,   Tacoma Wa.
 |  wengland@stephsf.com              +1 206 564 2122
 |
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sassan@locus.com (Sassan Behzadi) (09/13/90)

In article <363@stephsf.stephsf.com> wengland@stephsf.stephsf.com (Bill England) writes:
>
>  While Merge allows allocation of 'simulated' expanded memory I could not 
>  find any provision for allocating extended memory.  

ODT-DOS (Merge) *does* simulate EMS, but you will not be able to run 
programs that go into protected mode in order to access Extended Memory.

>  On further thought
>  it seems like a difficult proposition to create this feature under
>  Unix.

Well it ain't easy.

A few companies (Microsoft, Quarterdeck, Lotus, Borland, Locus and IGC) 
are now working on "DOS Protected Mode Interface" (DPMI) which would
allow DOS programs to access Extended Memory through a set of "well
defined" calls. Operating Systems that support virtual DOS sessions
and DPMI (potentially: Windows, DesqView, UNIX, and yes - even OS/2) 
can allow these DOS programs to access Extended Memory without sacrificing
system security.

Of course DOS programs have to be re-written in order to use DPMI.
So don't expect your current DOS application that goes into protected 
mode to run under these Operating Systems.

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Sassan Behzadi                                                          
sassan@lcc.COM                                                     
Locus Computing Corporation                                            
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