How to boot Real32 O/S?

Posted on 2011-05-02
Last Modified: 2012-05-11
I have an IBM 350-P90 computer which runs software that controls chemical dispensing valves.  This software runs on the Real32 operating system.  It is approximately 15 years old.  Today the computer has stopped loading the Real32 O/S and is now loading MS-DOS.  Subsequently, the dispensing software will no longer work.  Does anyone know how to force the boot sequence to start Real32 rather than MS-DOS?  Thanks.
Question by:StoneCutter3
    LVL 6

    Expert Comment

    You may insert a classical dos boot disk into the disk drive and continue from that.
    Note: change the bios setup to ensure system start boot from floopy.

    Hope this can answer your question.

    Author Comment

    Continue "what" from that?  I want to boot Real32
    LVL 7

    Expert Comment

    If there are more than 1 drive in the machine then you may have had a disk failure and now only the MS-DOS disk is seen.  Can you use the MS-DOS utility FDISK to LOOK at the partition table and post the results here?

    Also make sure that a MS-DOS boot floppy didn't get put in by accident.
    LVL 6

    Expert Comment

    Continue "what" from that?  
    The WHAT is depend on WHAT YOU HAVE.

    You can run your WHAT software if your WHAT software is located on the WHAT disk drive in your WHAT computer.

    Use your WHAT dos command to perform the above steps.

    I assume you know DOS command, else you need the technie to assist you.

    FYI, my primary school boy know simple dos since the age of 8. So, it should not difficult for you.

    LVL 38

    Expert Comment

    Hmmm.  The response to that last comment is going to be very interesting.

    yjchong514, there was no need for your childish sarcasm.  You neither addressed the question nor provided any useful information with which to work. You comment is similar to what other moronic imbeciles post on Yahoo Answers.

    Hi StoneCutter3

    Are you referring to the REAL/32 operating system by "Intelligent Micro Software (

    If so, I found this page which looks to be of interest:

    It looks like the first file you need to find and inspect is "LOADER.TXT" which apparently should contain a line of text "for each extra operating system added to the system over and above the original (native) operating system installed".  The typical example given is:
    REAL32.SYS M Real/32 7.53, current operating system.
    IMSMDOS.SYS M IMS Mdos 7.1 - previous version.

    That sounds to be something like the MS-DOS "config.sys" or "autoexec.bat" file, or actually more like the modern Windows text-based "boot.ini" file.

    It also seems from that page that you can fix the Boot Loader by running "LOADER.COM" from your DOS command line.  The .COM file is apparently expected in the "\the REAL32\BIN" directory of the hard drive.

    Personally I would avoid using any "FDISK /MBR" or "SYS C:" commands that you will also see in the page I linked to.  You appear to have nothing wrong with the default MS-DOS Master Boot Record and root boot files for DOS, so I don't think you need to mess with any of this.

    I think the "" command is what you need.

    Let us know if this seems to match what you are seeing.

    Author Comment


    Thanks for the response.  I tried the "LOAODER /U" and "LOADER LOADER.TXT" commands from the REAL32/BIN directory.  The messages from these commands seem to indicate a sucessful exection, yet, when I reboot the system it goes back to DOS.  I am in contact with the company (in England) that originally set up this machine and they also indicated that the LOADER command was the way to go.  With your confirmation of this approach I feel that I am close to an answer.  The UK company seemed to think that the reboot would stop and ask if REAL32 should be loaded.  Two other pieces of information.  1. A message (that I can't see) flashes on and off the screen just prior to starting MS-DOS, REAL32 trying to start?  2. The AUTOEXEC.BAT files has a statement that tests if %OS% is equal to "REAL32".  I was told by the UK company that AUTOEXEC.BAT would not be invoked if REAL32 was loaded.  I don't know if this is siginificant but the two pieces of information do not "fit".

    Let me know what you think.  Thanks.
    LVL 38

    Accepted Solution

    Hi StoneCutter

    Bear in mind here that I have never been exposed to the REAL/32 OS and that it has been a long while since I used MS-DOS.  I'm just going on what I was able to dig up and untuition.  Actually, here's a better page than the one I gave as it has links to other ones:

    OK, so "loader.txt" is similar to the Windows "boot.ini" in that it is read at a very early stage.
    IBMBIO.LDR is probably similar to NTLDR on recent Windows versions, and probably similar to the IO.SYS in DOS.

    "The UK company seemed to think that the reboot would stop and ask if REAL32 should be loaded".  Some stage isn't being reached and you aren't being able to see what flashes on and off before or as it's reaching that stage.

    Incidentall, using the command    loader   on its own rather than    might be running another program with a different extension named "loader".  There is a pecking order of what type of file would be run first if the extension isn't specified, and I'm sure .com will be up at the top, but loader.exe may take priority if a file of that name exists.  Although I doubt this, it may be worth checking just in case.

    It does seem odd that if the REAL32 boot loader kicks in as it should and autoexec.bat would never be read, that they should have an %OS% test in there. I can't recall when %OS% became a built-in environment variable, but I have a feeling it wasn't present in DOS where SET PATH= statements would more likely have been used.

    I suppose you could perhaps open Autoexec.bat and remark out the line by preceding it with a REM to test.  It probably has the Hidden and Read-Only attributes set, so from the DOS command line you would likely have to do this:

    attrib autoexec.bat

    If it shows H and R then remove the attibutes:
    attrib -h -r autoexec.bat
    and open it for Editing:
    edit autoexec.bat
    After editing and Saving (Alt +F > Alt + S > Alt + F > Alt + X in DOS EDIT), restore the attributes, eg.
    attrib +h +r autoexec.bat

    I think you really need to see what lines your "loader.txt" contains.  From the DOS command line you should be able to use:

    Again, check the attributes:
    attrib loader.txt
    and remove hidden attribute before opening in DOS EDIT to inspect.
    To see it, you might just be able to use this command:
    more < loader.txt

    Is there a REAL32.EXE file in the BIN folder?
    What happens if, from the DOS command line, you just launch it?

    I note from the company's "supprt policy" page:
    that they request a "SUPPORT.TXT" be generated by running "IMSD.EXE".
    I don't know how much gobbledegook that file may contain, but it might be worth having a look at it.

    In their troubleshooting page:
    I see that the OS has a "Safe Boot" option, ie. "booting the system in single user mode with no drivers loaded and no Upper memory used".  It's not clear from that how invoking it differes from the F3, F5, and F8 options from the previous versions, but I see that they use a configuration file named "MCONFIG.SYS" which seems to be equivalent to the DOS "config.sys":

    Apart from what I am reading, I really don't know anything more about REAL/32 though, so it's conjecture.
    LVL 7

    Assisted Solution

    I think the message that flashes on and off before DOS loads may very well be a DOS thing not the Real/32 OS.

    Author Closing Comment

    Thanks guys.  I ended up getting the answer from the UK company.  They sent me a LOADER.DAT file that contained the instructions to boot Real32.  I still don't know how the O/S load got corrupted.
    LVL 38

    Expert Comment

    hank you StoneCutter.  Glad you got it sorted out.
    LVL 38

    Expert Comment

    Whoops, Thanks

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