#94 Failure to boot jemmex/emm386 on Hyperv 2012

Kenneth Davis
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

    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.

  • 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!