DOS ain't dead

Hello,

I have recently upgraded my MS-DOS 7.1 system with the actual v5.80 version, however when JemmEx is loaded my system completely locks up for an unknown reason. (after the JemmEx loaded message under verbose).
I made a debug configuration,where I removed my option menus from the Config.sys, but I do load exactly the same drivers etc. and this does normally work.If I downgrade to v5.79 everything works fine even with my menu configuration.
I have also tried to configure the v5.80 without any extra parameters, just default,but same issue.
Did somebody experienced the same or have any clue, what could be causing the system to completely to lockup with the menu configuration? When I did the boot step by step, it locks up immediately after the JemmEx Loaded message.Before JemmEx I do load UMBPCI.

Thanks

> I have recently upgraded my MS-DOS 7.1 system with the actual v5.80
> version, however when JemmEx is loaded my system completely locks up for an
> unknown reason.

There's a readme supplied with Jemm with a chapter "troubleshooting, hints". Read this carefully and follow the hints!

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MS-DOS forever!

> > I have recently upgraded my MS-DOS 7.1 system with the actual v5.80
> > version, however when JemmEx is loaded my system completely locks up for
> an
> > unknown reason.
>
> There's a readme supplied with Jemm with a chapter "troubleshooting,
> hints". Read this carefully and follow the hints!

I did further testing, however I was not able to figure out why it freeze with the menu config.sys and not with the menu-less config, but found a solution.
I can't use the X=TEST parameter, this will still make the system to freeze, but I have to exactly define the range where it's occupied by ROM to be excluded and that is with X=A000-CFFF.Is this due to the more aggresive scan in v5.80 compared to what v5.79 does?

> I can't use the X=TEST parameter, this will still make the system to
> freeze, but I have to exactly define the range where it's occupied by ROM
> to be excluded and that is with X=A000-CFFF.Is this due to the more
> aggresive scan in v5.80 compared to what v5.79 does?

The "more aggressive scan" relates to the "I=TEST" option only. In v5.80, it does what is documented, in previous versions it only scanned "external" ROMs ( the VGA ROM, for example ).

X=TEST is not really useful on "modern" systems, since jemm ignores automatically all regions defined as reserved ( via BIOS call int 15h, ax=E820h ).

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MS-DOS forever!