#94 Failure to boot jemmex/emm386 on Hyperv 2012

Kernel (32)
wasnt nate

Greetings; I am playing around with Hyper-V 2012 RTM (build: 9200 final).

The it appears that it is not possible to boot with jemmex or emm386 driver. It does work the xmgr though.
The error message being reported is: ""System memory found at e000-efff, region might be in use"

If there is a jump starter on how to debug the boot loader I would be willing to do an initial investigation


  • Kenneth Davis

    Kenneth Davis - 2012-08-05

    Did you try Jemm with the following options?
    If that works then try with X=TEST NOHI NOVME NOINVLPG or just the NOVME NOINVLPG options generally needed in a virtual environment.
    Also are you using the latest version of Jemm (see http://www.japheth.de/Jemm.html ); see the site also for the best contact information of the author and source.
    The error seems to come from the extended memory manager not the kernel; please update with the results of using the latest Jemm with above mentioned options.
    Thank you.

  • Anthony Williams

    So Hyper-V 2012 RTM? I assume that means Win8 64-bit with VT-X? Yeah, try JEMM386 with "X=TEST I=TEST", but who knows what other complications may come from VT-X or cpu quirks. The mentioned "X=A000-FFFF" etc. is pretty useless, it's *extremely* conservative, only to see how far you can go without crashing. You can try it, but the point is if even that doesn't work (eh?), you're out of luck.

    I doubt you really need UMBs, do you? FreeDOS is pretty good at saving lots of low RAM without them. Though if you need EMS, your best bet may be either not using Hyper-V (in lieu of whatever else, too many options to mention) or such third-party freeware as EMM286 or EMSMAGIC. In rare cases, it may be more beneficial to just recompile the problematic end-user app to avoid EMS (if possible), but that's quite an extreme "solution".

    Anyways, good luck!

  • Burt Harris

    Burt Harris - 2014-08-28

    Reproduced reported error on Windows Server 2012 R2 Hyper-V installation from the fd11src.iso image downloaded from http://www.freedos.org/.

    While the root cause may be configuration of the extended memory manager, the configuration being used seems to be built into the installer that's part of the image. Perhaps these settings are too aggressive on saving memory, rather than something that gives the average joe confidence the install worked. Pressing '4' (excluding drivers) at the right time is a workaround, but if you don't do so, the error messages flash by so fast that I'm surprised anyone could read them.

    After running the FreeDOS installer, FDCONFIG.SYS contains the following line which seems most relevanedit at:


    but no amount of tweaking of this seemed to address the problem in configuration 1 running under Hyper-V, so I suspect the troublesome config line is elsewhere. Instead of fiddling further, what I've done is change the configuration menu default to the simplest one with:


    Note that the Windows 8 Hyper-V and Windows Server Hyper-V have differences that may be relevant to reproducing this problem: Windows 8 Hyper-V requires a processor with Second Level Address Translation (SLAT), while Windows Server Hyper-V doesn't. I known my host's Intel Q6600 processor has VT-X support, but lacks SLAT. I'm guesing this may be relevant.

    Host Processor  Intel(R) Core(TM)2 Quad CPU    Q6600  @ 2.40GHz, 2398 Mhz, 4 Core(s), 4 Logical Processor(s)
    Host BIOS Version/Date  Intel Corp. MQ96510J.15A.0379.2007.0913.1948, 9/13/2007
    VM Processor    Intel(R) Core(TM)2 Quad CPU    Q6600  @ 2.40GHz, 2398 Mhz, 1 Core(s), 1 Logical Processor(s)
    VM BIOS Version/Date    American Megatrends Inc. 090006, 5/23/2012
    Last edit: Burt Harris 2014-08-28

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