Ticket #10022 (closed enhancement: fixed)
[FIXED IN SVN] EMM386 does not automatically detect the available UMB regions
Reported by: | t6ti00 | Owned by: | |
---|---|---|---|
Component: | other | Version: | VirtualBox 4.1.6 |
Keywords: | Cc: | ||
Guest type: | other | Host type: | Windows |
Description (last modified by aeichner) (diff)
If MS-DOS virtual machine is created and EMM386.EXE is used, VirtualBox cannot automatically detect available UMB regions, so they are needed to setup manually to the CONFIG.SYS-file, like:
DEVICE=C:\WINDOWS\EMM386.EXE RAM ON NOEMS FRAME=NONE I=E000-EFFF I=B000-B7FF
On the contrary, Microsoft Virtual PC 2007 can do this. Command
DEVICE=C:\WINDOWS\EMM386.EXE NOEMS
is enough and UMB regions will be detected.
This is not a big problem for advanced users who are able to do a manual edit and people who are running only small programs on MS-DOS virtual machines may not need it at all. It can be confusing for the others. I do not consider this is a bug, so let's say that this is a feature request.
Thanks.
Attachments
Change History
comment:2 Changed 10 years ago by t0re76
it could be a software regression IMHO
running 4.2.6 r82870 64-bit
windows98 second edition setup after 20 seconds I got
Standard Mode: Fault outside of MS-DOS Extender. EC=0000 CS=0B17 IP=0B71 AX=8827 BX02B41 CX=0FDF DX=0000 SI=0000 DI=00F8 BP=8674 DS=0B57 ES=0FDF SS=0B57 SP=866E
comment:4 Changed 7 years ago by aeichner
- Status changed from new to closed
- Resolution set to obsolete
- Description modified (diff)
Please reopen if still relevant with a recent VirtualBox release.
Changed 6 years ago by squib
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attachment
VirtualBox Dos EMM386 failure.png
added
Screenshot showing failure
comment:5 Changed 6 years ago by squib
- Status changed from closed to reopened
- Resolution obsolete deleted
comment:8 Changed 5 years ago by bird
- Status changed from reopened to closed
- Resolution set to fixed
- Summary changed from EMM386 does not automatically detect the available UMB regions to [FIXED IN SVN] EMM386 does not automatically detect the available UMB regions
This should now be fixed in SVN. Will backport to 5.2 and 5.1 if it doesn't upset too many of our tests.
Your "solution" (and others I have found in various forums) of turning off EMS is no good when you need to run a program that requires EMS.
EMM386 issues a warning that memory is present in the I/O area (from B8000 thru EFFFF). Virtual Box is supposed to be virtualizing a PC compatible machine, right? Why isn't it emulating the "memory hole" properly? Real machines (generally) don't have read/write memory in that region, and if they do, it is a part of it, not the whole thing.
All of my attempts to use VBox for a legacy DOS app (that requires EMS) have failed.
This isn't just some little feature request, it *is* a major bug. A blocking bug for the primary use of virtualization outside of a datacenter: running legacy apps.