[comp.os.os2.misc] DOS and OS/2

db3l@arnor.UUCP (David Bolen) (03/15/91)

In article <oiHRy2w163w@isishq.fidonet.org> evanc@isishq.fidonet.org (Evan Champion) writes:

>I may be changing from DOS to OS/2 somewhen this year, but I don't want to 
>convert if I will not be able to use my current software (I have too much
>of a software investment for DOS, and don't have the funds to buy OS/2 
>versions of this software (in some cases there just isn't a os/2 version)
>
>Is there something like a convert program or something?  What about using
>the HPFS file system?  Will I be able to get my DOS files then?  Any help
>will be GREATLY appreciated.

If you aren't in a real rush to use OS/2 today or tomorrow, I think I'd
suggest that you wait until OS/2 2.0 is announced.  It will require a '386
machine, but that's not a problem in your case.

The current OS/2 (1.3) is really nice, and would run fine on your system,
but you'd probably be a little disappointed with the support for existing
DOS programs.  There is a single "DOS Box" that programs run in, and while
it is far from being useless, there are a good number of applications that
can have trouble running in it.  And in general, there is no simple
"conversion" process to make an OS/2 application out of a DOS one.

OS/2 2.0 however, will provide you with support for running up to 16 (I
think) DOS applications, each in their own DOS session, concurrently.  The
DOS sessions will also support multiple methods for accessing extended/expanded
memory and will be multitasked along with normal OS/2 sessions.  The current
OS/2 2.0 SDK provides about 620,000 bytes free in each DOS session, and when
2.0 is released, it should run any existing DOS application.  So you'll have
no conversion at all.  If you have a DOS application, run it in a DOS
session - if you have an OS/2 application, run it in an OS/2 session.

As for the HPFS file system, I personally think it's terrific, but it's
entirely optional.  If you do choose to install it, applications running in
the DOS Box(es) under either OS/2 1.x or 2.0 can access files on HPFS without
any problem.  They are, however, restricted to "seeing" files that fit the FAT
convention used by DOS (8.3 filenames) and won't support things like extended
attributes.  Oh, and if you boot true DOS from a diskette, you won't be able
to see the HPFS partition.

As for your machine, it sounds more than capable of handling OS/2.  OS/2 1.3
SE only requires 2MB and should run nicely in 4 (EE wants 3 so should also do
fine in 4).  The current version of the OS/2 2.0 SDK does recommend at least
6MB, but I expect that is due to the debugging kernel and other overhead of
the pre-release, and should drop closer to OS/2 1.3 by release.  Since OS/2 is
a virtual memory system, as long as you also have some disk space for
swapping, you can always run more stuff than your memory physically allows as
long as you are willing to put up with some swapping delays.  OS/2 2.0 changes
this to paging (similar to swapping, but using fixed size chunks of memory)
which is more efficient (both in time and memory/disk utilization).  You will
need maybe 10MB or so for the OS/2 installation (as a rough guess) or more
depending on what you install (if you get the development toolkit, or optional
components like LAN support).  Depending on how much of your 80MB drive is
taken up with existing data, you may end up wanting more disk space

Of course, more memory and disk space can always be utilitized, but I
wouldn't rush out and buy more stuff until you try OS/2 a bit.  Personally,
I've even used OS/2 1.2 on a 2MB 16Mz-386 (with a 60MB drive already chock
full of DOS data) without any problems, except for a swapping delay switching
between sessions.

--
-- David
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TURGUT@TREARN.BITNET (Turgut Kalfaoglu) (03/18/91)

No, there is no simple conversion between OS/2 and DOS.. However, I bet
that MOST of your applications will run in the DOS box of OS/2. I know,
because even most of my games work in the DOS box! (I play games while
taking backups onto diskettes)

You CAN use the HPFS (you can format a drive HPFS,and be able to access
that drive from the DOS box), but if you switch to an OS/2 screen and
create some files with long names, you won't be able to see those files
when you switch to DOS box - your applications won't be able to use
the long-named-files.

Regards, -turgut