Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!DBNUAMA1.BITNET!VBRANDT
From: VBRANDT@DBNUAMA1.BITNET
Newsgroups: comp.sys.atari.st
Subject: ETERNAL2 problem on megas (Was: Re: ZOO bombs)
Message-ID: <8908031514.AA06925@ucbvax.Berkeley.EDU>
Date: 3 Aug 89 15:14:59 GMT
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X-Unparsable-Date: Thu, 03 Aug 89 17:10:30 SET

In Info-Atari16 Digest #351, mcvax!ukc!reading!bru-cc!ralph@uunet.uu.net
(Ralph Mitchell) writes:

>ETERNAL2 doesn't actually work in a Mega 4...  Using HiSoft's resident
>monitor I have tracked it down to the bit where it checks to see if the
>ram disk is already resident.  It picks up the system variable that gives
>the physical top of memory and then fetches the word (or byte ?) from that
>location.  The location specified is one past the end of real memory, but
>the MMU is quite happy to return 0xFF for non-existent locations.  In the
>Mega 4, however, the non-existent location is beyond the maximum address
>that the MMU can handle, so it gets a real bus error.  Moshe ??

This was discussed several months (years? :-) ago when the Mega ST4 first came
out.  The ETERNAL2 RAM disk wasn't written by Moshe Braner, but by John Franco
(if I remember correctly).  The behavior you describe is indeed the problem.
I fixed it, added a few more features and emailed the resulting file to a few
people.  I can send you a copy if you want.

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