DOS ain't dead - JEMM(EX) and too much XMSHANDLES problem

JEMM(EX) and too much XMSHANDLES problem (Announce)

posted by Japheth , Germany (South), 14.03.2026, 03:57

> I observed one difference in behavior. Old JEMMEX allocated EMS page frame
> at E000 which seems to be used by BIOS. As I don't usually run EMS programs
> it didn't caused any problem. Newer JEMMEXes allocated EMS page frame at
> D000 which occupy all free UMB so then not available for drivers and TSR. I
> had to add FRAME=NONE (or NOEMS) to use D000 segment for UMB. I=TEST gives
> some little chunks in E000-FFFF region but too small to load bigger TSR
> in...

Yes, newer jemms respect reserved regions reported by int 15h ax=e820h

> Why the bug was not triggered on other systems? Something specific here?
> Nobody else reported such problem for years...

It only happens if jemm isn't allowed to move its resident part into the upper memory region ( by using option NOHI or X=A000-FFFF ). So it's not really a show-stopper...

> BTW does this JEMMEX contains also NMI fixes for AWE64 so I can have a
> single version?

Yes.

---
MS-DOS forever!

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Complete thread:

AweMidi - a Dos32Awe alternative - Japheth, 18.02.2026, 08:38 (Announce)
- AweMidi - a Dos32Awe alternative - Japheth, 23.02.2026, 08:13
- AweMidi - a Dos32Awe alternative - RayeR, 02.03.2026, 06:45
  - AweMidi - a Dos32Awe alternative - Japheth, 02.03.2026, 14:34
    - AweMidi - a Dos32Awe alternative - RayeR, 02.03.2026, 18:32
- JEMM(EX) and too much XMSHANDLES problem - RayeR, 09.03.2026, 04:28
  - JEMM(EX) and too much XMSHANDLES problem - Japheth, 09.03.2026, 12:54
    - JEMM(EX) and too much XMSHANDLES problem - RayeR, 09.03.2026, 15:00
    - JEMM(EX) and too much XMSHANDLES problem - RayeR, 10.03.2026, 02:12
      - JEMM(EX) and too much XMSHANDLES problem - Japheth, 10.03.2026, 08:44
        JEMM(EX) and too much XMSHANDLES problem - RayeR, 10.03.2026, 14:20
        JEMM(EX) and too much XMSHANDLES problem - RayeR, 11.03.2026, 03:44
        JEMM(EX) and too much XMSHANDLES problem - Japheth, 11.03.2026, 07:51
        JEMM(EX) and too much XMSHANDLES problem - RayeR, 12.03.2026, 01:54
        JEMM(EX) and too much XMSHANDLES problem - Japheth, 12.03.2026, 08:11
        JEMM(EX) and too much XMSHANDLES problem - RayeR, 12.03.2026, 14:03
        JEMM(EX) and too much XMSHANDLES problem - Japheth, 12.03.2026, 15:18
        JEMM(EX) and too much XMSHANDLES problem - RayeR, 12.03.2026, 16:36
        JEMM(EX) and too much XMSHANDLES problem - bretjohn, 12.03.2026, 23:35
        JEMM(EX) and too much XMSHANDLES problem - RayeR, 13.03.2026, 02:30
        JEMM(EX) and too much XMSHANDLES problem - Japheth, 13.03.2026, 08:43
        JEMM(EX) and too much XMSHANDLES problem - Japheth, 13.03.2026, 15:07
        JEMM(EX) and too much XMSHANDLES problem - RayeR, 14.03.2026, 02:47
        JEMM(EX) and too much XMSHANDLES problem - Japheth, 14.03.2026, 03:57
        JEMM(EX) and too much XMSHANDLES problem - RayeR, 16.03.2026, 21:57
        JEMM(EX) and too much XMSHANDLES problem - Japheth, 17.03.2026, 12:05
        JEMM(EX) and too much XMSHANDLES problem - RayeR, 17.03.2026, 13:39
        JEMM(EX) and too much XMSHANDLES problem - Japheth, 17.03.2026, 17:46