Hi Jack,

First of all, let me clear one MISSUNDERSTANDING... The EMM386 that 
works ok is from Michel Devore, which was extensevely tested by the 
members of FreeDOS.

Most of your answer regards Gates&Co product, sory for the confusion

About the A20 issue. I used it because I had a very stange problem: 
after a crash (with only XMS) the machine never booted again from the 
disk!!! I had to boot once from a CD and reboot adain from the disk. 
That never happend to me and is completely unheard of...

Alain

Em 18-10-2011 23:25, Jack escreveu:
>
> I am DISMAYED by some of the recent comments on this board
> regarding "old EMM386" v.s. JEMM386/JEMMEX, the "A20" line
> etc.!
>
> First, I use and recommend JEMM386/JEMMEX with my UIDE and
> other drivers.   I absolutely REFUSE using "old EMM386" by
> Gates&  Co. because it has (A) Never-fixed BUGS in its VDS
> logic, (B) FAR too much "Custom Crap" for wretched Win/311
> as anyone can "see" in its 1.8-MB of source files, and (C)
> is a 125- or 130K driver that "eats" FAR too much run-time
> memory!   "It sucks!" in short, and I view UIDE "lucky" to
> be able to use its OWN UltraDMA, instead of what Gates and
> all his "flunkies" left us with as "DMA" when they DROPPED
> MS-DOS in 1995!   I also want NOTHING to do with FD-EMM386
> and anyone who wonders why can read the Revision Notes for
> JEMM386, to view all of what Japheth had to do BEFORE poor
> old FD-EMM386 worked even "plausibly" as the new JEMM386!
>
> Re: JEMM386/JEMMEX failing on some systems, this is likely
> due to "modern" address spaces that the JEMM drivers can't
> detect.   But Japheth once told me that he CHOSE to retain
> all of EMM386's memory-detection logic, so his drivers are
> "compatible" with what Gates&  Co.'s [never updated] TRASH
> will do!    So, do you really expect EMM386 will do a much
> better job of detecting memory??   I would NOT!!   If some
> system has a "problem" loading JEMM386, or loading EMM386,
> its user MUST "experiment" with the I= and X= commands, to
> selectively include/exclude address areas, until a desired
> EMM driver DOES load successfully!   Never-was, and never-
> will-be a "fully automatic" PC system, and sometimes a few
> experiments loading drivers (mine included) are NECESSARY!
>
> Finally, it is a bit "LATE in the game!" to be thinking of
> new schemes for handling the "A20" line.   My own XMGR has
> exactly 4 methods:
>
>    (A) IGNORE "A20" if it is found "enabled" when XMGR loads
>         i.e. the DOS kernel turns it on forever.
>    (B) Use keyboard-port logic if /PN was given.
>    (C) Use port 92h i.e. IBM PS/2 logic if /PA was given.
>    (D) "Ask the BIOS" if port 92h logic is there, if neither
>        /PA nor /PN is given.
>
> XMGR doesn't handle the usually-ignored BIOS calls, any of
> the "ancient" Compaq, H/P, ATT 6300 or other 1990s-vintage
> schemes to handle "strange A20 logic" (all of which caused
> Gates&  Co. HIMEM.SYS to reach 30K!), etc.    Except for a
> "bug" in its port 92h logic, back in 2009, nobody has ever
> "complained" to me that XMGR's "A20" logic was inaccurate,
> inadequate, etc.!
>
> So, why don't we just leave current "A20" handling as-is??
> For 99.44% of us, it works fine!   Any "strange" system on
> which it does not work usually needs TROUBLE-shooting, NOT
> yet-another new "A20 handling" scheme!!
>
>
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