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Date: Thu, 06 Jul 2000 08:21:14 -0700
To: opendos AT delorie DOT com, opendos AT delorie DOT com
From: Mike Sensney <msensney AT owt DOT com>
Subject: Re: DR-DOS upper memory problem
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At 09:19 AM 07/06/2000 GMT, Alex Venn wrote:
>I've been using an old Packard Bell 486 and have come across a weird
>memory instability which suggests that in some circumstances the DR-DOS
>EMM386 can be unreliable in it's tests for ROM areas. Every so often I
>experienced a lot of EMM386 errors and crashes, while at other times the
>same mix of programs was stable. Eventually I discovered that sometimes
>EMM386 saw the whole of the upper memory area from 768k to 1Mb as RAM
>and claimed to have stuck data where the video and system ROM was
>supposed to be.
>Eventually I used the ROM option to shadow the ROM areas identified by
>MFT and since then not a crash (AUTO also appeared to be inconsistent).
>I can't say how common a problem this is, but it may be one explanation 
>for some of the reported instability of the DR-DOS EMM386.
>
>The only question I now have is, how reliable a memory mapper is MFT ? 
>Also, is there a better or free alternative ? (or are QEMM and DV really
>free nowadays ?)

I think you identified the real problem in your first line:
>I've been using an old Packard Bell 486

It is difficult to judge the reliability of any software running on flakey
hardware.