Path: utzoo!attcan!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!unido!wrkof!cat!martin
From: martin@cat.uucp (Thomas Martin)
Newsgroups: comp.os.os2.misc
Subject: Re: DOS Extended memory Support Under OS/2 R2.0
Message-ID: <1990Oct6.181227.11104@cat.uucp>
Date: 6 Oct 90 18:12:27 GMT
Organization: C.A.T. Kommunikations-System
Lines: 48


klimas@iccgcc.decnet.ab.com (klimas@iccgcc.decnet.ab.com) schrieb am  5.10.:
> Can someone clarify what kind of extended and expanded memory support
> OS/2 2.0 will provide for the DOS box.  The latest issue of BYTE's
> supplement has an article on OS/2 2.0 that implies that OS/2 2.0 will
> support DOS programs that use extended as well as expanded memory running
> from the DOS box.  Is this accurate and what are the gotchas?

According to an IBM publication (spring 90) describing the features of OS/2
2.0, the DOS compatibility box will have the following characteristics:

- 4.0 compatability
- Due to the usage of the V86 mode of the 80386/80486 it will be possible to
terminate a hung DOS session from the shell.
- The usage of the V86 mode will enable up to 16 concurrent DOS sessions.
Each operating in its own linear 1MB address space.
- DOS applications will run full-screen, windowed or iconized in the
background.
- OS/2 2.0 will leave more than 600K to DOS applications.
- It will support both, EMS and Extended Memory.
- DOS asynchronous communications applications can support communication
speeds of up to 9600 baud.
- DOS sessions are now capable of multitasking.
- EMS capability allows DOS applications to allocate and access up to 32 MB
of expanded mamory in up to 255 EMS objects.
- Due to the V86 mode it will be possible to use vitual memory for DOS
sessions virtually making the usable memory unlimited.

Due to the early stage this article was published, the author pointed out
that some features may be changed or abandoned but I personally think we
will all find them to be true in the final product because all of these
great DOS features are due to the usage of the V86 mode and therefor part of
the underlying hardware.

Another advantage of the V86 mode will be that now the processor will operate
solely in its protected mode (the V86 mode is protected) eliminating
the time-consuming switch from real to protected mode and back necessary for
operating DOS in the 1.x versions.

I hope that helps a little bit.

Regards,

Thomas

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  Thomas Martin (martin@cat.de)                     
  C.A.T. Kommunikations-System, Frankfurt