Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!lll-lcc!well!dsmall
From: dsmall@well.UUCP (David Small)
Newsgroups: comp.sys.amiga
Subject: Re: How 'Bout HyperCard!
Keywords: HyperCard, Mac, Magic Sac
Message-ID: <5965@well.UUCP>
Date: 15 May 88 19:02:28 GMT
References: <15372@uflorida.cis.ufl.EDU>
Reply-To: dsmall@well.UUCP (David Small)
Organization: Whole Earth 'Lectronic Link, Sausalito, CA
Lines: 59


(The discussion centers around Hypercard & a little Magic Sac'isms.)

  I spent a few months very recently hacking Magic Sac into the Amiga
and have some news -- well, you *did* say you were looking for Magic Sac
news, right?  Anywho.
First, it has to run in flickermode, otherwise you can't see enough of the
screen to do much good. A flicker fixer would be important. Second, the Amiga
apparently can read the outer 32 tracks of Mac disks -- not the inner 48,
however. Third, there's a big problem in the memory mapping that I can't
overcome, and that's why I'm putting the project on hold.

On the Mac, RAM memory starts at location 0 and extends upwards for
however much memory you have. The memory manager is designed around this --
it compacts the heap, and so forth, during program operation. On the
Amy 500, you've got 512K in low memory, which is fine, then a 11 megabyte
"hole" in the memory map, then another (optional) 512K. I can't get the
Mac OS to work with this for several reasons.
   Hence, the largest "emulated Mac" I can bring is up at a 256K Mac --
not real useful. 512K is sort of a starting point anymore for Mac software.
Hypercard assumes 1 meg.

   Anywho, over the last two weeks I've reached the conclusion that it's
just not worth doing; the resulting product wouldn't be powerful enough.
This honestly doesn't have anything to do with Apple, the Lawsuit, or
anything else.

   The reason the Magic Sac for the Amiga is so late is that two seperate
consultant groups failed to make it work, over a two year period. The last
person to try it more or less gave up in March '88; I see he showed up at
the BADGE meeting, broke his non disclosure agreement, and gave several
compeltely wrong reasons for why it was being dropped. 

During those two years, I was much too busy on the Atari end of things to
do work on the Amiga end. After giving up on outsiders doing it (in about
February), I got a 500 and hard disk, and hacked it together. It took
roughly the same time as the ST version -- about 3 months -- to bring up.

  Anyway, I don't know what to do about the memory map problem. Perhaps
a smaller "
hole" in RAM can be tolerated in the auto-configure memory machines, if
their mapping is moved down as closely as possible to the 512K chip ram.
It is also possible that the new 1-meg chipset will help; I'd hate to see
a Magic Sac dependent on a retrofit, though. Add to this the flicker mode,
and the disk drive <> Mac format directly, and it's just not practical for
me right now.

   I know of a foreign-developed 128K ROM 
Mac emulator for the A-1000 that runs with both Kickstart and the 512K
"regular" RAM; that looks interesting. It runs Multifinder, so it's
pretty compatible, and Hypercard is right over the horizon with a 1 meg
chip set. Since I don't see any source for 128K ROMs in the US that's legit,
I don't think I could market it.

   Sorry for the lengthy note, but I've owed this newgroup some news for
a long time.

 -- Dave Small
(formerly, Data Pacific)