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XMS in Pure DOS

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  • XMS in Pure DOS

    What is the maximum amount of RAM DOS 6.22 can address ?

    Just replaced my suspect 64 Mb with a 128 Mb SDRAM module.
    The BIOS can see it but DOS 6.22 MEM reports only 64 Mb.
    The Processor is a Celeron and the Motherboard supports 768 Mb.

    B.t.W. Is there a way to make the Forum rememember Passwords
    associated with UserNames ?

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  • #2
    I think 64MB is all that the memory managers can see in DOS6.22 upwards.
    If you are looking to get the maximum usable under 640K, with careful setting up, you should see 617KB, with all drivers loaded high.
    Using DOS7, ie WIN95/98 DOS with MSDOS.SYS line: BootGUI=0, you can see as much as 624KB with careful tuning.
    Using QEMM, I can get as much as 629KB.

    To get your password to stick, use Gator or similar utility (but watch out for spyware!)
    Also, I think that IE 5.5 does this as well.

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    [This message has been edited by David J Walker (edited March 08, 2002).]

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    • #3
      What is the maximum amount of RAM DOS 6.22 can address ?
      See Knowledge Base articles Q239514, Q116256.

      Just replaced my suspect 64 Mb with a 128 Mb SDRAM module. The BIOS can see it but DOS 6.22 MEM reports only 64 Mb. The Processor is a Celeron and the Motherboard supports 768 Mb.
      I find it somewhat ironic that Microsoft OSs have problems with large amounts of (physical) memory. I recently upgraded my PC to 1 GB of RAM, and Windows 95 refused to boot. I later discovered from the Microsoft web site that it must be told to limit itself to only 768 MB.
      If you try to make something idiot-proof, someone will invent a better idiot.

      Comment


      • #4
        [QUOTE]Originally posted by OTTO WIPFEL:
        [B]What is the maximum amount of RAM DOS 6.22 can address ?

        This is my fist time in here, so...yay me...

        Switch to DR-DOS 7.03...

        Copy the Himem.sys and (if you want EMS) the EMM386.EXE from Win98/ME and DR-DOS shows ALL available XMS.
        Alternatiely, Putting the Win Himem.sys with the DR-DOS EMM386.EXE gives a printed but non fatal error and allows the multitasker to use ALL available RAM (on my system, thats 256Mb with up to 32Mb allocated per task.
        I advise this only for people who don't want to burden themselves with having to use the crippled DOS that comes with Windows...or rely on the Win API to do their multitasking in DOS...


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        Comment


        • #5
          ___________________________________________________________
          by Otto Wipfel :
          What is the maximum amount of ram DOS 6.22 can address ?
          ___________________________________________________________

          It depends on the memory manager, not the OS.

          MS-DOS 6.22 does not include an expanded-memory manager for
          physical expanded memory, since each expanded-memory board
          requires its own memory manager. To use physical expanded memory,
          you must install the memory manager that came with your expanded-memory board.

          EMM386, which comes with the MS-DOS, is a memory manager but
          not part of the OS.

          ---------------------------------------------------------------------------

          P.S. A DOS program does not have direct access to the information
          in the expanded memory. Instead, expanded memory is divided into 16K
          segments call "pages". When a program requests information that is
          in expanded memory, the expanded-memory manager(compatibility with
          the Lotus/Intel/Microsoft Expanded Memory Specification) maps or copies
          the appropriate page to an area called a "page frame"(exists in the upper
          memory area).A program gets the information from the page frame.


          Regards


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          [This message has been edited by John Lee (edited March 11, 2002).]

          Comment


          • #6
            To get the Forums to remember your username & password, the
            next time you're in the Forums, click on the "Preferences"
            link at the top of the page. From within the page that comes
            up, you can tell the Forums BBS to put a cookie in your browser
            that will remember your username & password for up to a year.

            Regards,


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            Clay C. Clear

            mailto:[email protected][email protected]</A>
            Clay Clear's Software (Frames Only)
            My website is still under construction.

            [This message has been edited by Clay Clear (edited March 11, 2002).]

            Comment


            • #7
              OTTO,

              I have used himem.sys and hooked it to directly access up to 8GB
              directly. If you hook the himem.sys you can hit 64MB at a time.
              By hooking the ems routine and then creating banks of handles
              (himem.sys default # of banks are 32) you look at a one huge
              linear address space. It is pretty cool. If you take the basic
              64MB x 32 (base handles) that gives you 2GB directly. By then
              modifiying the himem.sys line in the config.sys with the
              numhandles=128 option then you have access to up to 8GB and it is
              fast!

              If you are doing disk access and use DMA transfers the transfer
              rate becomes darn near close to theoretical. Dump one big buffer
              from disk to memory and then back again. It is tres' cool.

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              Comment


              • #8
                You said it Mark, "Tres Cool", which is an Understatement

                Stuff like this comes up only now and then. When it does is goes into
                my "Knowledge Base" for future reference. Learned a lot from you guys
                in the Forum over the years !

                Thanks.


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